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NASA/KSC ACRONYM LIST

    A
    
    3AAL    Three Axis Acoustic Levitator
    A       Angstrom
    A       Acceleration
    A       Aft
    A       Alpha
    A       Ampere
    A       Analog Signal
    A&A     Advertise and Award
    A&E     Architects and Engineering
    A&E     Architectural and Engineering
    A&I     Assembly and Installation
    A&L     Approach and Landing
    A&P     Attitude and Pointing
    A&PS    Administration and Program Support (MSFC Directorate)
    A&R     Automation and Robotics
    A&RC    Application and Resource Control
    A&TA    Assembly and Test Area
    A&V     Assembly and Verification
    A/A     Air to Air
    A/C     Air Conditioning
    A/C     Aircraft
    A/C     Associate Contractor
    A/D     Analog to Digital
    A/E     Activity Elements
    A/E     Architectural and Engineering
    A/F     Air-to-Fuel Ratio
    A/FM    Air/Firing Mechanism
    A/G     Air to Ground
    A/L     Approach/Landing
    A/L     Approach and Landing/Autoland
    A/L     Airlock
    A/L     Autoland
    AA      Antenna Assembly
    AAA     Avionics Air Assembly
    AAC     Aft Access Closure
    AAFE    Aeroassist Flight Experiment
    ABC     Audio Bus Coupler
    ABCL    As Built Configuration List
    ABHRS   As Built Hardware Reporting System
    ABOLT   Acquire Bolt
    AC      Alternating Current
    AC      Assembly Complete
    AC      Comptroller Office
    ACBM    Active CBM
    ACC     Aft Cargo Carrier
    ACCMS   Advanced Checkout, Control, and Maintenance System
    ACCS    Advanced Checkout and Control System
    ACES    Acoustic Containerless Experiment System
    ACIP    Assembly Configuration and Integration Panel
    ACO     Assembly and Checkout Officer
    ACP	Automated Change Processing
    ACR     Active Cavity Radiometer
    ACRIM   Active Cavity Radiometer Irradiance Monitor
    ACRBC   Acceptance, Checkout, Retest, and Backout Criteria
    ACRC    Assured Crew Return Capability - Now ACRV
    ACRV    Assured Crew Return Vehicle
    ACS     Advanced Camera for Surveys (Hubble Space Telescope)
    ACS     Atmosphere Control Systen
    ACS     Attitude Control System
    ACSM    ACS Moding
    ACTS    Advanced Communications Technology Satellite
    ACU     Arm Computer Unit
    ACU     Arm Control Unit
    AD      Active Device
    AD      Aperture Door
    AD      Attachment Device
    ADC     Affiliated Data Center
    ADEOS   Advanced Earth Observing Mission
    ADF     Air Diffuser
    ADP     Acceptance Data Package
    ADP     Automated Data Processing
    ADPS    Acceptance Data Package System
    ADS	Attitude Determination System
    ADSF    Advanced Directional Solidification Furnace
    AEA     Antenna Electronics Assembly
    AEG     AEG Telefunken
    AEPI    Atmospheric Emission Photometric Imaging
    AERO	Aerodynamic
    AERO	Aerosurfaces
    AERO	Atmospheric Flt Supt
    AES	Analog Event System
    AES     Atmosphere Exchange System
    AES	Auger Electron Spectroscopy
    AESC	Aerojet Electrosystems Company
    AESD    Airlock External Stowage Devices
    AESE    Airborne Electrical Support Equipment
    AET	Aerosurface End-to-End Test
    AETL	Approved Engineering Test Laboratory
    AEWG	Active Experiment Working Group
    AF	Aft Fuselage
    AF	Airframe
    AF	Air Force
    AF	Audio Frequency
    AFA	Airframe Assembly
    AFAD	Armed Forces Acquisition Document
    AFALD	Air Force Acquisition Logistics Division (WPAFB)
    AFB     Air Force Base
    AFC	Aerodynamic Flight Control
    AFC	Automatic Flight Control
    AFC	Automatic Frequency Control
    AFCE	Automatic Flight Control Equipment
    AFCS	Automatic Flight Control System
    AFD     Aft Flight Deck
    AFD	Assistant Flight Director
    AFDCP	Aft Flight Deck Control Panel
    AFDO	Aft Flight Deck Operator
    AFDPDB	Aft Flight Deck Power Distribution Box
    AFE	Aeroassist Flight Experiment
    AFE     American Flight Echocardiograph
    AFEB	Award Fee Evaluation Board
    AFEC	Award Fee Evaluation Committee
    AFETR	Air Force Eastern Test Range (ESMC preferred)
    AFETRM	Air Force Eastern Test Range Manual
    AFF	Acceptance and Ferry Flight
    AFFTC	Air Force Flight Test Center (Edwards AFB)
    AFGE	Association of Federal Government Employees
    AFGL	Air Force Geophysics Laboratory
    AFGWC	Air Force Global Weather Center
    AFI     Air Force Instruction (Most AFRs have been changed to AFIs.)
    AFI	Automatic Fault Isolation
    AFL	Autoland Flight Tests
    AFLC	Air Force Logistics Command
    AFM	Air Force Manual
    AFO	Announced Flight Opportunity
    AFO	Announcement of Flight Opportunities
    AFP     Air Force Program
    AFPD	Authorization for Program Development
    AFPRO	Air Force Plant Representatives Office
    AFR     Air Force Regulation
    AFRPL	Air Force Rocket Propulsion Laboratory (EAFB)
    AFRSI	Advanced Flexible Reusable Surface Insulation
    AFS	Air Force Standard
    AFSC	Air Force Systems Command
    AFSCF   Air Force Satellite Control Facility
    AFSCF	Air Force Satellite/Spacecraft Control Facility
    AFSCN	Air Force Satellite Control Network
    AFSIG	Ascent Flight Systems Integration Group
    AFSSD	Air Force Space Systems Division
    AFSWC	Air Force Special Weapons Center (Holloman AFB)
    AFT	Aerodynamic Flight Test
    AFT	Atmospheric Flight Test
    AFT	Autogenic Feedback Training
    AFTA	Acoustic Fatigue Test Article
    AFTA	Aft Frame Tilt Actuator
    AFTE    Autogenic Feedback Training Experiment
    AFTEC	Air Force Test and Evaluation Center
    AFV	Antiflood Valve
    AFZES	Analytical Float Zone Experiment System
    AG	Artificial Gravity
    AG	Attitude Gyro
    AGAA	Attitude Gyro Accelerometer Assembly
    AGAP	Attitude Gyro and Accelerometer Package
    AGB     Adjustable Grapple Bar
    AGOSS   Automated Ground Operations Scheduling System
    AHU     Air Handling Unit
    AI      Artificial Intelligence
    AIM     Aeronomy of Ice in the Mesosphere
    AIM     Automated Informed Maintenance
    AIMS    Automated Informed Maintenance System
    AIO     Analog Input/Output
    AIRS    Atmospheric Infrared Sounder
    AIS     Action Item Sheet
    AIS     Airlock Illumination Subassembly
    AIS     Analog-In Single-Ended
    AIST    Agency of Industrial Science and Technology
    AIT     Aeritalia
    AIU     Abort Interface Unit
    AIU     Avionics Interface Unit
    AJ      Assembly Jig
    AKM     Apogee Kick Motor
    A/L     Approach and Landing
    A/L     Autoland
    AL      Air Lock
    AL/EMU  Airlock/Extravehicular Mobility Unit
    ALAE    Atmospheric Lyman Alpha Experiment
    ALAS    Approach Landing Autopilot System (Subsystem)
    ALAS    Automatic Landing Autopilot Subsystem
    ALC     Aft Load Controller
    ALC     Air Logistics Center
    ALC     Audio Load Compensator
    ALC     Augmented Landing Site
    ALC     Automatic Level Control (Camera)
    ALC     Automatic Light Control
    ALCA    Aft Load Control Assembly
    ALCA    Automatic Level Control Assembly
    ALDO    Activity Level Dependent Operations
    ALE     Airport Landing Equipment
    ALE     Airport Lighting Equipment
    ALERT   Acute Launch Emergency Reliability Tip
    ALGOL   Algorithmic Language
    ALIO    Activity Level Independent Operations
    ALM     Alarm
    ALPHA   Angle of Attack (Pitch)
    ALPHA   Right Ascension
    ALPS    Approach and Landing Procedures Simulator	
    ALRUTS  Automated Line Replaceable Unit Tracking System
    ALS     Advance Logistics System
    ALS     Advanced Launch System
    ALS     Airlock System (ECLS)
    ALS     Alternate Landing Site
    ALS     Approach Landing System
    ALS     Automatic Landing System
    ALSA    Astronaut Life Support Assembly
    ALSARM  Advanced Life Support Automated Remote Manipulator
    ALSE    Astronaut Life Support Equipment
    ALSS    Airlock Support System (Subsystem)
    ALT     Alternate
    ALT     Altimeter
    ALT     Altitude
    ALT     Approach and Landing Test
    ALTM    Altimeter
    ALTR    Approach and Landing Test Requirement
    ALU     Arithmetic Unit
    AM      Actuator Mechanism
    AM      Administration and Management Operations (KSC Directorate)
    AM      Alpha Meter
    AM      Ammeter
    AM      Amplitude Modulation
    AM      Antenna Management
    AMA     Air Material Area (now Air Logistics Centers)
    AMB     Ambient
    AMC     AMERICOM satellite
    AMC     Automatic Mixture Control
    AMCA    Aft Motor Control Assembly
    AMCP    ADL Master Control Program
    AMDS    Advanced Missions Docking Subsystem
    AMEC    Aft Master Events Controller
    AMF     Abort Motor Facility
    AMF     Apogee Motor Firing
    AMF     Astronaut Memorial Foundation
    AMG     Activation Management Group
    AMI     Absolute Memory Image
    AMI     Airspeed Mach Indicator
    AMI     Alpha/Mach Indicator
    AML     Approved Materials List
    AMLC    Asynchronous Multiline Controller
    AMOOS   Advanced Maneuvering Orbit-to-Orbit Shuttle
    AMP     Ampere
    AMPR    Aeronautical Manufacturers Planning Report
    AMPR    Aeronautical Manufacturers Progress Report
    AMPS    Atmosphere, Magnetosphere, and Plasmas in Space
    AMPS    Atmospheric Magnetospheric Plasma System
    AMPTE   Active Magnetospheric Particle Tracer Explorers
    AMPU	Automated Maneuver Planning Utility
    AMR     Atlantic Missile Range
    AMRV    Astronaut Maneuvering Vehicle
    AMS     Acoustic Measurement System
    AMS     Actuation Mechanism Subsystem
    AMS     Amplifier
    AMS     Amplifier Subsystem
    AMSU    Advanced Microwave Sounding Unit
    ANSI    American National Standard Institute
    AO      Assembly Order
    AO      Atomic Oxygen
    AOA     Abort Once Around
    AOA     Annual Operating Agreement
    AOH     Assembly Operations Handbook
    AOP     Assembly Ops
    AP      Application Processor
    AP      Associated Press
    APAS    Androgynous Peripheral Attachment System
    APC     Adaptive Payload Carrier
    APCS    Automated Project Control System - ARTEMIS
    APCU    Assembly Power Converter Unit
    APDS    Androgynous Peripheral Docking System
    APFR    Articulating Portable Foot Restraint
    API     Application Programming Interface
    APID    Applications Process Identification
    APM     Advanced Pressurized Module
    APM     Attached Pressurized Module
    APPCM   Arm Pitch Plane Change Mode
    APS     Acquisition Processor Subsystem
    APS     Automated Payload Switch
    APS     Auxiliary Power Supply
    AR      Atmosphere Revitalization
    ARC     Ames Research Center
    ARC     Aggregation of Red Cells
    ARCU    American-to-Russian Converter Units
    ARIS    Active Rack Isolation System
    ARM     Accident Report Meeting
    ARP	Automated Release Processing
    ARS     Air Revitalization System
    ARS     Archive and Retrieval Subsystem (PPCU)
    ARTEMIS Project Management Software System - Metier Product
    ARTS    Automated Resource Tracking System - ARTEMIS
    ASCII   American Standard Code for Information Interchange
    ASCR    Assured Safe Crew Return
    ASDA    Area Smoke Detector Assembly
    ASE     Airborne Support Equipment
    ASP     Attitude Sensor Package
    ASRC	Arctic Slope Regional Corporation
    ASRS    Automated Support Requirements System
    ASSY    Assembly
    AST     Astro Star Tracker
    ASTER   Advanced Spaceborne Thermal Emission and Reflection Radiometer
    ASTG    Aerospace Test Group
    ATC     Absolute Time Command
    ATCS    Active Thermal Control System
    ATE     Automated Test Equipment
    ATLAS   Atmospheric Laboratory for Applications and Science
    ATMOS   Atmospheric Trace Molecule Spectroscopy
    ATP     Accelerated Training Program
    ATP     Acceptance Test Procedure
    ATP     Authorization to Proceed
    AWAD    Assembly Work Authorization Document
    
    B
    
    B       Bit
    B&P     Budgetary and Planning
    B&W     Black and White
    B-1 DIV B-1 Division (Rockwell)
    B/A     Bank Angle
    B/A     Barometric Altimeter
    B/A     Buffer Amplifier
    B/C     Bench Check
    B/L     Baseline
    B/O     Booster Orbiter
    B/O     Breakout
    B/O     Burnout
    B/SC    Brake Skid Control
    B/SMPL  Bits per Sample
    B/U     Backup
    B/V     Bleed Valve
    B/W     Black and White
    B/sec   Bits per Second
    BA      Bank Angle
    BA      Breathing Air
    BAC     Boeing Aircraft Company
    BAC     Booster Assembly Contractor
    BAC     Buffer Access Card
    BACS    Body Axis Coordinate System
    BAI     Barometric Altitude Indicator
    BAIR    Breathing Air
    BAL     Balance
    BAN     Budget Allocation Notice
    BARB    Ballast Aerating Retrieval Boom
    BARO    Barometer
    BARS    Baseline Accounting and Reporting System
    BASD    Ball Aerospace Systems Division
    BASIS	Business and Support Information Services
    BASS    Backup Avionics System Software
    BATT    Battery
    BB      Breadboard
    BBC     Before Business Clearance
    BC      Battery Charger
    BC      Binary Counter
    BC      Bus Coupler
    BCCT    Break Control Command Transducers
    BCD     Binary Coded Decimal
    BCE     Backup Control Electronics
    BCE     Bus Control Element
    BCFS    Backup Flight Control System
    BCH     Binary Coded Hexadecimal
    BCH     Bose-Chaudhuri-Hocquenghem (Computer Code)
    BCN     Beacon
    BCP     Base Condemnation Percent
    BCP     Benchmark Control Point
    BCR     Bar Chart Report
    BCRD    Basic Consolidated Requirements Document
    BCRT    Binary Code Range Time
    BCT     Bus Configuration Table
    BCU     Bus Control Unit
    BCWP    Budget Costs for Work Performed
    BCWS    Budget Costs for Work Scheduled
    BD      Band
    BD      Binary Decoder
    BD      Binary Digit
    BD      Binary Discrete
    BD      Board
    BDA     Backup Drive Amplifier
    BDA     Bermuda Island
    BDA     Bermuda (STDN)
    BDA     Blast Danger Area
    BDA     Backup Drive Amplifier
    BDC     Bi-Directional Converter
    BDC     Bit Error Rate
    BDCF    Baseline Data Collection Facility
    BDCR    Baseline Document Change Request
    BDD     Baseline Definition Document
    BDRT	BFS Discrepancy Report Tracking  
    BDT     Block Data Transfer
    BDY     Body
    BDYFLP  Body Flap
    BECO    Booster Engine Cutoff
    BER     Bit Error Rate
    BESS	Biological Experiment Scientific Satellite
    BESS	Biomedical Experiment Scientific Satellite
    BESS	Biomedical Experiment Support Satellite
    BEST    Black Employee Strategy Team 
    BEST 	Booster Exhaust Study Test
    BET	Best Estimate of Trajectory
    BETA ANGLE   Sideslip Angle
    BEWS	Blast Environment Wave Simulator
    BF	Beat Frequency
    BF	Body Flap
    BFC     Backup Flight Control
    BFC	Backup Flight Controller
    BFC	Body Flap Control
    BFCS    Backup Flight Control System
    BFL	Back Focal Length 
    BFL	Bakersfield (TACAN Station)
    BFO	Beat Frequency Oscillator
    BFRP	Boron Fiber Reinforced Plastics
    BFS     Backup Flight System
    BFZES	Breadboard Float Zone Experiment System
    BH/MP	Breather Hose/Mouthpiece
    BHD	Bulkhead
    BHN	Brinell Hardness Number
    BHP	Brake Horsepower
    BHS	Base Heat Shield
    BIA	Bus Interface Adaptor
    BIN	Business and Information Network
    BIPROP	Bipropellant
    BIO	Bio Research Module
    BIO	Biological
    BIO	Bioseparation
    BIOMED	Biological Medicine (Medical)
    BIOS	Biological Satellite
    BIS	Biocide Injection System
    BIT	Binary Digit
    BIT	Built-in Test
    BITE    Built-in Test Equipment
    BIU	Buffer Interface Unit
    BIU	Bus Interface Unit
    BK	Back
    BK	Brake
    BKHD	Bulkhead
    BLK     Block
    BLOW    Booster-Lift-Off Weight
    BLR     Boiler
    BLS     Bottom Left Side
    BLV     Bleed Valve
    BLWR    Blower
    BM      Basal Metabolism
    BM      Business (Branch) Manager
    BM      Body Mounted
    BMA     Body-Mounted Accelerometer
    BMAG    Body-Mounted Attitude Gyro
    BMAP    Buffer Map
    BMB     Base Maintenance Building
    BME     Bench Maintenance Equipment
    BMFT    German D-1 Spacelab Payload
    BMMD    Body Mass Measuring Device
    BMS     Background Measurement Satellite
    BMU     Bus Monitor Unit
    BN      Ballistic Number
    BO      Breakout Box
    BOB     Best on Best
    BOC     Base Operations Contract
    BOD     Beneficial occupancy Date
    BOE     Break of Entry
    BOF     Beginning of File
    BOI     Break of Integrity
    BOM     Beginning of Month
    BOM     Bill of Materials
    BOP     Baseline Operations Plan
    BOPACE  Boeing Plastic Analysis Capability for Engines
    BOS     Backup Operating System
    BOS     Bright Object Sensor
    BOT     Beginning of Tape
    BOT     BOTSWANA (STDN)
    BOW     Bill of Work
    BP      Back Pressure
    BP      Bandpass
    BP      Barber Pole
    BP      Blood Pressure
    BP      Boilerplate
    BPD     Baseline Program Documentation
    BPI     Bits per Inch
    BPM     Beats per Minute
    BPMS    Blood Pressure Measuring System
    BPR     Bypass Ratio
    BPS     Bits Per Second
    BPT     Body Point
    BPV     Bipropellant Valve
    BR      Bit Rate
    BRAVO   Business Risk and Value of Operation in Space
    BRCS    Basic Reference Coordinate System
    BRG     Bearing
    BRK     Brake
    BRKT    Bracket
    BRM     Biological Research Module
    BRPM    Breath Rate per Minute
    BRRS    Banana River Repeater Station
    BRS     Bottom Right Side
    BRT     Bright
    BS      Block Specification
    BSC     Brake Skid Controller
    BSDP    Booster Stage Discharge Pressure
    BSE     Booster Systems Engineer
    BSI     Basic Shipping Instructions
    BSI     Boeing Services International, Inc.
    BSM     Booster Separation Motors
    BSM     Booster separation motor
    BSR     Basic System Release
    BSR     Bite Status Register
    BSRM    Booster Solid Rocket Motor
    BSS     Backup System Services
    BSTR    Booster
    BT      Burn Time (Engine)
    BTC     Bus Tie Contractor
    BTC     Binary Time Code
    BTMS    Body Temperature Measuring System
    BTR     Burn Time Remaining
    BTR     Boom Time Remaining
    BTR     Bus Transfer
    BTU     Bus Terminal Unit
    Btu     British Thermal Unit
    BU      Backup
    BUC     Backup Computer
    BUC     Buckhorn, CA (GSTDN)
    BUFF    Buffer
    BUOU    Backup Optical Unit
    BUR     Backup Rate
    BW      Bridgewire
    BW      Bandwidth
    BX      Box
    BY      Budget Year
    BYP     Bypass
    
    C
    
    C       	Candle
    C       	Capacitance
    C       	Celsius
    C       	Centigrade
    C       	Coefficient
    C       	Complete
    C       	Constant
    C       	One Hundred
    c       	Cycle
    C&D     	Control and Display
    C&DH    	Command and Data Handling
    C&DS    	Command and Data Simulator
    C&M     	Control and Monitoring
    C&T     	Communications and Tracking
    C&TSS   	Communication and Tracking Subsystem
    C&W     	Caution and Warning
    C3VP	        Canadian CloudSat/CALIPSO Validation Project
    C-Band  	3900 to 6200 MHz
    C-BD    	C-Band
    C-C     	Carbon-Carbon
    C-to-C  	Computer-to-Computer
    C/C     	Combustion Chamber
    C/D     	Countdown
    C/F     	Center Frequency
    C/L     	Checklist
    C/L     	Closed Loop
    C/O     	Changeout
    C/O     	Checkout
    C/O     	Contamination/Overpressure
    C/O     	Cutoff
    C/P     	Cold Plate
    C/R     	Commutation Rate
    C/S     	Counts per Second
    C/SCSC  	Cost/Schedule Control Systems Criteria
    C/W     	Carrier Wave
    C/W     	Caution and warning
    CA      	California
    CA      	Carrier Aircraft
    CA      	Contingency Abort
    CA      	Cone Angle
    CA      	Contract Award
    CA      	Corrective Action
    CA      	Cost Account
    CAB     	Cabin
    CAB     	Cabinet
    CAB     	Civil Aeronautics Board
    CAB     	Cost Audit Board
    CACB    	Center Aisle Connector Bracket
    CACC    	Communications and Configuration Console
    CACON   	Cargo Container
    CAD     	Computer Aided Design
    CAD/CAM         Computer Aided Design
    CADE    	Controller/Attitude-Direct Electronics
    CADS    	Command and Data Simulator
    CADSI   	Communications and Data Systems Integration
    CADU    	Control and Display Unit
    CAE             Common Application Environment
    CAE             Computer-Aided Engineering
    CAIB		Columbia Accident Investigation Board
    CAL     	Calibrate, Calibration
    CAL     	Cornell Aeronautical Laboratory
    cal     	Calories
    CALC    	Calculate
    CALIPSO	        Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation
    CAM     	Carrier Aircraft Modification
    CAM     	Centrifuge Accommodations Module
    CAM     	Computer Aided Manufacturing
    CAM     	Computer Annunciation Matrix
    CAM     	Content Addressable Memory
    CAMR    	Camera
    CAN     	Certification Analysis Network
    CAP     	Capacitor, Capacity
    CAP     	CCMS Application Programs
    CAP     	Computer Application Program
    CAP     	Contractor Acquired Property
    CAP     	Cost Account Package
    CAP     	Crew Activity Plan
    CAPCOM  	Capsule Communicator
    CAPPS		Checkout, Assembly and Payload Processing Services
    CAPRI   	Captive Reset Igniter
    CAPS    	Common Attitude Pointing System
    CAPS		Corrective Action Problem System
    CAPS		Crew Activity Planning System
    CAPS    	Crew Altitude Protection Suit
    CAPSIM  	Captive Simulation
    CAR     	Certification Approval Request
    CAR     	Configuration and Acceptance Review
    CAR     	Corrective Action Request
    CARID   	Customer Acceptance Review Item Disposition
    CARR    	Customer Acceptance Readiness Review
    CAS     	Calibrated Airspeed
    CAS     	Command Augmentation System
    CAS     	Control Augmentation System
    CASE            Computer Aided Software Engineering
    CASO    	Cancellation Addendum Sales Order
    CASP    	CDS Application Support Programs
    CASS    	CITE Augmentation Support System
    CATEG   	Category
    CAU     	Command Acquisition Unit
    CAU     	Command Activation Unit
    CAU     	Customer Acquisition Unit
    CAUSE		Computer Aided User Oriented System Evaluation
    CAUT    	Caution
    CB      	Center of Buoyancy
    CB      	Circuit Breaker
    CB      	Constant Bandwidth
    CB/ac   	Circuit Breaker (ac only)
    CB/dc  		Circuit Breaker (dc only)
    CBA     	C-Band Transponder Antenna
    CBA     	Collective Bargaining Agreement
    CBACS           Common Badging and Access Control System
    CBC     	Complete Blood Count
    CBE     	Connector Bracket, Experiment
    CBIL    	Common and Bulk Items List
    CBM             Common Berthing Mechanism
    CBP     	Connector Bracket Power
    CBrF3   	Bromotrifluoromethane (Fire-Extinguishing Material)
    CBS     	Connector Bracket Signal
    CBSA    	Cargo Bay Stowage Assembly
    CBV     	Cabin Bleed Valve
    CBW     	Constant Bandwidth
    CBX     	C-Band Transponder
    CC      	Carbon-Carbon
    CC      	Channel Controller
    CC      	Chief Counsel (KSC Directorate)
    CC      	Communications Control
    CC      	Cost Center
    CC      	Crew Compartment
    CC      	Crew(s) Certified
    CCA     	Communications Carrier Assembly
    CCA     	Contract Change Authorization
    CCA     	Coolant Control Assembly
    CCAFS   	Cape Canaveral Air Force Station
    CCAS		Cape Canaveral Air Station
    CCATS   	Command, Communication, and Telemetry System
    CCB     	Configuration Change Board
    CCB     	Change Control Board
    CCB     	Configuration Control Board
    CCBD    	Configuration Control Board Directive
    CCC             Central Communications Center
    CCC     	Central Computer Complex
    CCC     	Communication(s) Control Console
    CCC     	Complex Control Center
    CCC     	Contaminant Control  Cartridge
    CCC     	Controller Checkout Console
    CCD     	Charge Coupled Device
    CCD     	Checkout Command Decoder
    CCD     	Constants Change Display
    CCDR    	Contractor Critical Design Review
    CCE     	Computer Command Engineer
    CCF     	Converter Compressor Facility
    CCFF    	Cape Canaveral Forecast Facility
    CCIR    	International Radio Consultative Committee
    CCL     	Closed Circuit Loop
    CCL     	Commonality Candidate List
    CCL     	Configuration Control Logic
    CCM     	Controlled Carrier Modulation
    CCM     	Crew/Cargo Module
    CCME    	Contract Change Mass Estimate
    CCMS    	Checkout, Control and Monitor System
    CCMS    	Checkout, Control, and Monitor Subsystem (LPS)
    CCMS		Command Control and Monitor System
    CCN     	Contract Change Notice
    CCN     	Contract Change Negotiation
    CCOH    	Corrosive Contaminants, Oxygen, and Humidity
    CCP     	Center Console Panel
    CCP     	Configuration Control Phase
    CCP     	Commercial Change Proposal
    CCP     	Cost Control Program
    CCP     	Charge Capacitance Probe
    CCP     	Contract Change Proposal
    CCP     	Configuration Control Panel
    CCP     	Configuration Change Point
    CCP     	Computer Control Panel
    CCR		Configuration Change Request
    CCR     	Contractor Change Request
    CCR     	Control Center Rack
    CCR             Corner Cube Retroflectors
    CCRA    	Cape Canaveral Reference Atmosphere
    CCRF    	Consolidated Communication Recording Facility
    CCS     	Central Control Section
    CCS     	Central Control Station
    CCS     	Command and Communication System
    CCS     	Command and Control Subsystem
    CCS     	Complex Control Set
    CCS     	Computer Core Segment
    CCS     	Console Communication System
    CCS     	Contamination Control System
    CCSCS		Consultive Committee for Space Data Systems
    CCSSO  		Council of Chief State School Officers
    CCT     	Computer Compatible Tape
    CCT		Cost Committment Team
    CCTE    	Conditioned Cargo Transport Equipment
    CCTV    	Closed Circuit Television
    CCU     	Camera Control Unit
    CCU     	Central Control Unit
    CCU     	Communications Carrier Unit
    CCU     	Crewman Communications Umbilical
    CCV     	Chamber Coolant Valve
    CCVA    	Chamber Coolant Valve Actuator
    CCW     	Counterclockwise
    CCIM    	Command Computer Input Multiplexer
    CD      	Center Director (KSC Directorate)
    CD      	Change Directive
    CD      	Coefficient of Drag
    CD      	Command Decoder MDM
    CD      	Contractual Data
    cd      	Candella (Luminous Intensity)
    CDA     	Command and Data Acquisition
    CDA     	Critical Design Audit
    CDB     	Central Data Buffer
    CDB     	Command Data Base
    CDBFR   	Common Data Buffer
    CDC     	Confined Detonating Cord
    CDC     	Control Data Corporation
    CDC     	Countdown Clock
    CDCE    	Cosmic Dust Collection Experiment
    CDCR    	Contractor Drawing Change Request
    CDDF    	Center Director's Discretionary Fund
    CDDS    	Command and Data System
    CDDT    	Countdown Demonstration Test
    CDF     	Cable Distribution Frame
    CDF     	Central Data Facility
    CDF     	Circuit Design Fabrication
    CDF     	Confined Detonating Fuse
    CDF     	Cool-Down Facility
    CDF&TDS 	Circuit Design, Fabrication, and Test Data Systems
    CDH     	Constant Delta Height
    CDI     	Course Deviation Indicator
    CDM     	Communications/Data Manager
    CDMS    	Command and Data Management Subsystem
    CDMS    	Command and Data Management System
    CDN     	CDR Discrepancy Notice
    CDNB    	CDR Discrepancy Notice Board
    CDOS    	Customer Data and Operations System
    CDP     	Command Data Processor
    CDPIS   	Command Data Processing and Instrumentation System
    CDQR    	Critical Design and Qualification Review
    CDR     	Cleaning, Decontamination Request
    CDR     	Commander
    CDR     	Critical Design Review
    CDRL    	Contract Data Requirements List
    CDROM           Compact Disk Read Only Memory
    CDRR    	Component Design Requirements Review
    CDRR    	Contract Documentation Requirements Records
    CDS     	Central Data Subsystems (LPS)
    CDS     	Central Data System
    CDS     	Closeout Door System
    CDS     	Collision Detector System
    CDS     	Control Data Corporation
    CDS     	Control Data System
    CDSC    	Communications Distribution and Switching Center
    CDT     	Central Daylight Time
    CDT     	Command Descriptor Table
    CDT     	Compressed Data Tape
    CDT     	Configuration Data Table
    CDT     	Countdown Time
    CDU     	Computer Display Unit
    CDU     	Control and Display Unit
    CDU     	Coupling Data Unit
    CDU     	Coupling Display Unit
    CDU     	CRT Display Unit
    CDW     	Command Data Word
    CDW     	Computer Data Word
    CE      	Change Evaluation
    CE      	Civil Engineering
    CE      	Control Element
    CE      	Cost Element
    CE      	Current Expendable
    CE&IS   	Combined Elements and Integration Systems
    CEA     	Control Electronics Assembly (for MMU)
    CEC     	Control Electronics Container
    CEC     	Control Encoder Coupler
    CECP    	Compatibility Engineering Change Proposal
    CEDC    	Cycling Error Detection Code
    CEI     	Configuration End Item
    CEI     	Contract End Item
    CEIAC   	Coastal Engineering Information Analysis Center
    CEIT    	Crew Equipment Integration Test
    CEIT    	Crew Equipment Interface Test
    CELSS   	Controlled Environment and Life Support System
    CELV    	Complementary Expendable Launch Vehicle
    CEP     	Circular Error Probable
    CEQ     	Council on Environmental Quality
    CER     	Cost Estimating Relationship
    CERT    	Certification
    CERV    	Crew Emergency Return Vehicle
    CES     	Control Electronics System
    CES     	Crew Escape System
    CESC    	Canadian Space Agency Engineering Support Center
    CETA    	Crew and Equipment Translation Aid
    CETF    	Critical Evaluation Task Force
    CEU     	Control Electronics Unit
    CEV		Crew Exploration Vehicle
    CF      	Carrier Frequency
    CF      	Center Forward
    CF      	Centrifugal Force
    CFD     	Computational Fluid Dynamics
    CFD     	Continuous Flow Diffusion
    CFD     	Converter, Frequency to dc Voltage
    CFE     	Contractor Furnished Equipment
    CFES    	Continuous Flow Electrophoresis System
    CFI     	Card Format Identifier
    CFLSE   	Critical Fluid Light Scattering Experiment
    CFM     	Customer Furnished Material
    CFM     	Cubic Feet per Minute
    CFMF    	Crip Flow Management Facility
    CFP     	Conceptual Flight Profile
    CFR     	Code of Federal Regulation
    CFRP    	Carbon Fiber Reinforced Plastics
    CFSTI   	Clearinghouse for Scientific and Technical Information (now NTIS)
    CFT     	Common Facilities Test
    CFU     	Colony Forming Unit
    CFY     	Company Fiscal Year
    CG      	Center of Gravity
    CGAU    	Cabin Gas Analysis Unit
    CGC     	Command Guidance Computer
    CGCD    	Crossed Grid Charge Detector
    CGF     	Crystal Growth Furnace
    CGG     	Contingency Gravity Gradient
    CGP     	Central Grounding Point
    CGSS    	Cryogenic Gas Storage Subsystem
    CH      	Channel
    CH4     	Methane
    CHAMP   	Comet Halley Active Monitoring Program
    CHAN    	Channel
    CHAR    	Character
    CHASE   	Coronal Helium Abundance Spacelab Experiment
    CHCS    	Cabin Humidity Control Subsystem
    CHeCS   	Crew Health Care System
    CHG     	Change
    CHG     	Charge
    CHGR    	Charger
    CHL     	Certified Hardware List
    CHL     	Channel
    CHMBR   	Chamber
    CHR     	Cooper-Harper Rating
    CHROMEX 	Chromosome and Plant Cell Division in Space
    CHS     	Collimated Hole Structure
    CHUTE   	Parachute
    CHX     	Cabin Heat Exchanger
    CI      	Certification Inspection
    CI      	Color Interior Film
    CI      	Configuration Inspection
    CI      	Configuration Item
    CI      	Continuous Interlock
    CI      	Course (deviation display) Invalid
    CI      	Crew Interface
    CIA     	Control Interface Assembly
    CIAP    	Climatic Impact Assessment Program
    CIAR		Change Implementation/Assessment Record
    CIB     	Change Impact Board
    CIB     	Change Implementation Board
    CIC     	Command Interface Control
    CIC     	Communications Interface Coordinator
    CIC     	Continuing Improvement Council
    CIC     	Control and Information Center
    CIC     	Crew Interface Coordinator
    CICA    	Competition in Contracting Act
    CICC    	Cargo Integration Control Center
    CICU    	Computer Interface Conditioning Unit
    CICU    	Computer Interface Control Unit
    CID     	Charge Injection Device
    CID     	Computer Interface Device
    CIDL    	Configuration Item Data List
    CIDR    	Critical Intermediate Design Review
    CIE     	Communications Interface Equipment
    CIE     	Computer Interface Electronics
    CIF     	Central Instrumentation Facility
    CIFS    	Critical Initial Flaw Size
    CIG     	Cable Integrity Group
    CIG     	Communications and Interface Group
    CIL     	Critical Items List
    CIM     	Computer Input Multiplexer
    CIMS            Cyber Identity Management System
    CIN     	Center Information Network
    CIN     	Change Identification Number
    CINDAS  	Center for Information and Numerical Data Analysis and Synthesis
    CIO             Chief Information Officer
    CIP     	Coordinated Instrument Package
    CIP     	Customer Integration Panel
    CIR     	Cargo Integration Review
    CIR     	Change Incorporation Record
    CIR     	Circle
    CIR     	Circulate
    CIR     	Configuration Inspection Report
    CIRC    	Circularization Burn, OMS2
    CIRCUM  	Circumference
    CIRHS   	Critical Items and Residual Hazards List
    CIRRIS  	Cryogenic Infrared Radiance Instrument for Shuttle
    CIS             Center for Internet Security
    CIS     	Central Integration Site
    CIS     	Change Impact Summary
    CIS     	Communication Interface System
    CIS     	Component Identification Sheet
    CIS     	Contractor's Information Submittal
    CIS     	Customer Information System
    CISS    	Centaur Integrated Support Structure
    CIT     	Critical Item Tag
    CITE    	Cargo Integration Test Equipment
    CIU     	Communications Interface Unit
    CIU     	Computer Interface Unit
    CIU     	Controller Interface Unit
    CIV     	Critical Ionization Velocity
    CIVT    	Cargo Interface Verification Test
    CJC     	Cold Junction Compensator
    CK      	Check
    CKAFS   	Cape Kennedy Air Force Station (Changed to CCAFS)
    CKPT    	Checkpoint
    CKRA    	Cape Kennedy Reference Atmosphere (Changed to CCRA)
    CKS     	Checks
    CKT     	Circuit
    CL      	Centerline
    CL      	Close (Closed)
    CL      	Closed Loop
    CL      	Closed Loop Control Logic
    CL      	Cluster
    CL      	Coefficient of Lift
    CL      	Commonality List
    Class   	Classification
    CLC     	Change Letter Control
    CLC     	Critical Load Cycle
    CLCS    	Checkout and Launch Control System
    CLDST   	Closed Loop Dynamic Stability Test
    CLG     	Ceiling
    CLIN    	Contact Line Item Number
    CLIP    	Combined Laser Instrumentation Package
    CLM     	Care Logic Module
    CLMC    	Central Logistics Management Center
    CLN             Change Leaders Network
    CLNR    	Cleaner
    CLOC    	Canadian Logistics Operation Center
    CLR     	Clear
    CLRB    	Cost Limit Review Board
    CLS     	Contingency Landing Site(s)
    CLSO    	Contingency Landing Support Officer
    CLT     	Closed Loop Test
    CLUSTER 	International Solar Terrestrial Physics Program
    CLV		Crew Launch Vehicle
    CM      	Cargo Management
    CM      	Center of Mass
    CM      	Common Module
    CM      	Configuration Management
    CM      	Consumables Management
    CM      	Control Monitor
    CM      	Crew Module
    cm      	Centimeter
    CM&S    	Communications Maintenance and Storage
    CMA     	Configuration Management Accounting
    CMA     	Cylindrical Mirror Assembly
    CMACS   	Central Monitor and Control System
    CMAO    	Contract Management Assistance Officer
    CMAT    	Compatible Materials (List)
    CMC     	Command Module Computer
    CMC     	Crew Module Computer
    CMD     	Command
    CMD     	Contamination Monitor Package
    CMD DCDR     	Command Decoder
    CMG     	Control Moment Gyroscope
    CMM     	Condition Monitored Maintenance
    CMN     	Crewman
    CMO     	Configuration Management Office
    CMOS    	Complementary Metal Oxide Silicon
    CMP     	Configuration Management Plan
    CMPR    	Compare
    CMPRT   	Compartment
    CMPTD   	Computed
    CMPTR   	Computer
    CMPTR ACTY  	Computer Activity
    CMR     	Center Materials Representative
    CMRB    	Contractor Material Review Board
    CMRR    	Common Mode Rejection Ratio
    CMS     	Competency Management System
    CMS-2   	Cambridge Monitoring System (IBM Computer Program)
    CMSI    	Checkout/Control and Monitor Subsystem Interface
    CMTS    	Computerized Maintenance Test System
    CMV     	Common Mode Voltage
    CN      	Change Notice
    CNDS    	Condensate
    CNRL    	Communications and Navigation Research Laboratory
    CNSL    	Console
    CNTL    	Control
    CNTR    	Counter
    CNTRL   	Control
    CNTRL   	Controller
    CNWDI   	Critical Nuclear Weapons Design Information
    CO      	Carbon Monoxide
    CO      	Cargo Operations (KSC Directorate)
    CO      	Change Order
    CO      	Contracting Officer
    CO      	Cutoff
    CO2     	Carbon Dioxide
    COA     	Center Operations Area
    COAS    	Course Optical Alignment Sight
    COAS    	Crew(man) Optical Alignment Sight
    COAS    	Crewman optical alignment sight
    COAX    	Coaxial, Coaxial Cable
    COB     	Communications Office Building
    COBE    	Cosmic Background Explorer
    COBOL   	Common Business Oriented Language
    COC     	Close-Open-Close
    COD     	Center Operations Directorate (JSC)
    COE     	Corps of Engineers
    COF		Central Operations Facility
    COF     	Columbus Orbital Facility
    CoF     	Construction of Facilities
    C of F  	Construction of Facilities
    C of F  	Cost of Facilities
    COFI    	Checkout and Fault Isolation (on Board)
    COFR   		Certificate of Flight Readiness
    COFW    	Certificate of Flight Worthiness
    COI             Coast Orbital Insertion
    COI             Composite Optics, Inc.
    COIM    	Checkout Interpreter (Software) Module
    COL     	Checkout Language
    COL     	Coast Orbital Insertion
    COLD-SAT        Cryogenic on Orbit Liquid Depot-Storage, Acquisition, Transfer
    COLM    	Column
    COM     	Common, Commonality
    COM     	Computer Output Microfiche
    COM-M   	Common Mode
    COMAS   	Combined Orbital Maneuvering and Abort System
    COMAT   	Compatibility of Materials
    COMB    	Combustion
    COMEC   	Communications Security
    COMEDS		Continental U.S. Meteorological Data System
    COMM    	Communications
    COMMAND 	Computer Command Engineer
    COMP    	Compass
    COMP    	Compensate
    COMP    	Component
    COMP    	Computation of Rendezvous Targeting
    COMP    	Computer
    COMPEN  	Compensator
    COMPL   	Completed
    COMPOOL 	Common Data Pool
    COMPR   	Compress, Compressor
    COMPT   	Compartment
    COMR&DSAT 	Communication Research and Development Satellite
    COMSAT  	Communications Satellite
    COMSEC  	Communications Security
    COMTEL		Compton Telescope
    CON     	Contact
    CONCN   	Concentration
    COND    	Condenser
    COND    	Condition, Conditioner
    CONDR   	Conditioner
    CONF    	Conference
    CONFIG  	Configuration
    CONN    	Connect, Connector
    CONS    	Console
    CONSTR  	Construct, Construction
    CONT    	Container
    CONT    	Contingency
    CONT    	Continue, Continued, Continuous
    CONTAM  	Contaminate
    CONTIG  	Contiguous
    CONTR   	Control, Controller
    CONUS   	Continental United States
    CONV    	Converter
    COOP    	Cooperative
    COORD   	Coordinate
    COP     	Contingency Operations Plan
    COP		Co-orbiting Platform
    COPV            Composite Overwrapped Pressure Vessel
    COQ     	Certificate of Qualification
    COR     	Contracting Officer Representative
    CORE    	Common Operational Research Equipment
    COS     	Carry-on Oxygen System
    COS     	Console Operating System
    COS		Co-orbiting Satellite
    COS     	Cosine
    COSATI  	Committee on Scientific and Technical Information
    COSI    	Closeout System Installation
    COSMIC		Coherent Optical System of Modular Imaging Collectors
    COSPAR		Committee on Space Research
    COSS		Centaur Operations at the Space Station
    COSTA   	Cost Accounting (Code)
    COTR    	Contracting Officer's Technical Representative
    COTS    	Commercial Off the Shelf
    COV     	Cutoff Valve
    CP      	Candle Power
    CP      	Cargo Program Office (KSC)
    CP      	Cargo Projects Office (KSC)
    CP      	Center of Pressure
    CP      	Chemically Pure
    CP      	Circular Pitch
    CP      	Cold Plate
    CP      	Console Processor
    CP      	Control Panel
    CP      	Control Point
    CP-DPO  	Deployable Payloads Projects Office (KSC)
    CP-FEO  	Cargo Facilities and GSE Projects Office (KSC)
    CP-PCO  	Cargo Projects-Program Control Office
    CP-SPO  	Spacelab Projects Office (KSC)
    CPA     	Contingency Planning Aid
    CPA     	Critical Path Analysis
    CPAF    	Cost Plus Award Fee
    CPC     	Central Planning Center
    CPC     	Characteristics Properties Code
    CPC     	Computer Program Component
    CPCB		Crew Procedures Control Board
    CPCEI		Computer Program Contract End Item
    CPCI    	Computer Program Change Instruction
    CPCI		Computer Program Configuration Item
    CPCL    	Computer Program Change Library
    CPCL    	Computer Program Control Library
    CPCR    	Computer Program Change Request
    CPCR    	Crew Procedures Change Request (Form 482)
    CPD     	Converter, Pulse to dc Voltage
    CPD     	Crew Passive Dosimeter
    CPD     	Crew Procedures Division
    CPDDS		Computer Program Detail Design Specification
    CPDR    	Contractor's Preliminary Design Review
    CPDS		Computer Program Design (or Development) Specification
    CPDS    	Crew Procedures Documentation System
    CPE		Change Package Engineer
    CPE     	Chief Program Engineer
    CPE		Continuous Particle Electrophoresis
    CPEI    	Computer Program End Item
    CPES    	Crew Procedures Evaluation (Evaluator) Simulator
    CPF     	Cargo Processing Facility
    CPF     	Central Processing Facility
    CPF     	Cost Per Flight
    CPFF    	Cost Plus Fixed Fee
    CPG     	Change Planning Group
    CPI     	Cost Performance Index
    CPI     	Cross Pointer Indicator
    CPIF    	Cost Plus Incentive Fee
    CPL		Capillary Pump Loop
    CPL     	Couple
    CPLT    	Complete
    CPM     	Computer Program Module
    CPM     	Critical Path Method
    CPM     	Cycles per Minute
    CPMP    	Crew Procedures Management Plan
    CPP		Competitive Placement Plan
    CPR     	Critical Problem Report
    CPS		Canadian Payload Specialist		
    CPS     	Cycles Per Second
    CPSE    	Common Payload Support Equipment
    CPSS    	Cold Plate Support Structure
    CPSS    	Critical Phase System Software
    CPT     	Cargo Processing Technician
    CPT     	Computer Program Tapes
    CPU     	Central Processing Unit
    CPU     	Computer Printer Unit
    CQCM		Cryogenic Quartz Crystal Microbalance
    CQDR    	Critical Qualification Design Review
    CR      	Card Reader
    CR      	Certification Requirement
    CR      	Change Request
    CR      	Configuration Review
    CR      	Control Room
    CR      	Crew
    CR&T		Command, Ranging, and Telemetry
    CR/DIR  	Change Request Directive
    CRAF		Comet Rendezvous Asteroid Flyby
    CRAS    	Cost Reduction Alternative Study
    CRB     	Change Review Board
    CRBD		Change Review Board Directive
    CRC     	Contractor Recommended Code
    CRC     	Cost Reduction Curve
    CRD     	Change Request Disposition
    CRDG		Contamination Requirements Definition Group
    CRDP    	Computer Resources Development Plan
    CRES    	Corrosion Resistant Steel
    CRG     	Change Review Group
    CRG     	Correspondence Review Group
    CRIS    	Calibration Recall and Information System
    CRISP   	Computer Resources Integrated Support Plan
    CRIT    	Critical
    CRM     	Chemical Release Module
    CRMD    	Computer Resources Management Data
    CRN     	Cable Routing Rotation
    CRN     	Contract Revision Number
    CRO     	Cathode Ray Oscillograph(s) or Oscilloscopes
    CRP     	Configuration Requirements Processing
    CRPL    	Cosmic Ray Physics Laboratory
    CRR     	Computer Run Report
    CRR     	Critical Requirements Review
    CRS     	CO2 Reduction Subsystem
    CRS     	Course
    CRS     	Cross
    CRSFD   	Crossfeed
    CRSI    	Ceramic Reusable Surface Insulation
    CRSVR   	Crossover
    CRT     	Cathode-Ray Tube
    CRTG    	Cartridge
    CRW     	Control Read/Write
    CRYO    	Cryogenic
    CRYT		Cryogen Tank
    CS      	Change Status
    CS      	Checkout Station
    CS      	Clean Sheet
    CS      	Common Set
    CS		Communications System
    CS      	Consumables Status
    CS      	Control Segment
    CS      	Core Segment
    CS      	Crew Station
    CS      	Spacelab Operations Directorate
    CS      	STS Cargo Operations (KSC Directorate)
    CSA		Canadian Space Agency
    CSA     	Cyclic Strain Attenuator
    CSAA		Committee on Space Astronomy and Astrophysics
    CSAM    	Crinkled Single Aluminized Mylar
    CSAS    	Computerized Status Accounting System
    CSAT    	Combined Systems Acceptance Test
    CSC     	Computer Sciences Corporation
    CSC     	Conical Shaped Charge
    CSC     	Contingency Support Center (CCAFS)
    CSC     	Cosecant Computing Amplifier
    CSCB    	Contractor's Summary Cost Breakdown
    CSCSAT  	Commercial Synchronous Communication Satellite
    CSD     	Chemical Systems Division
    CSD     	Control System Development
    CSD     	Crew Systems Division
    CSDD    	Control Systems Development Division (JSC)
    CSDF    	Central Source Data File
    CSDL    	Charles Stark Draper Laboratory (MIT)
    CSDT    	Computer Software Data Tapes
    CSE		Catalytic Surface Effects Experiment
    CSE     	Common Support Equipment
    CSE     	Communications Systems Engineer
    CSE     	Computer Support Equipment
    CSE     	Configuration Switching Equipment
    CSF     	Central Supply Facility
    CSF     	Cost Sensitivity Factor
    CSI     	Coelliptic Sequence Initiation
    CSI     	Control Servo Input
    CSI		Controls-Structures Interactions
    CSI     	Crew Software Interface
    CSIR    	Computer Systems (Hardware/Software) Integration Review
    CSIU    	Core Segment Interface Unit
    CSL     	Command Signal Limiter
    CSL     	Computer Status Lights
    CSL     	Crew Systems Laboratory
    CSM     	Command Service Module
    CSM     	Common Support Module
    CSM     	Computer Status Matrix
    CSOC    	Consolidated Space Operations Center
    CSOP    	Crew Systems Operating Procedures
    CSP     	Computer Support Program
    CSPU    	Core Segment Processing Unit
    CSR     	Certification Status Report
    CSR     	Check Signal Return
    CSR     	Crew Station Review
    CSRP    	Computers and Software Review Panel
    CSS     	Computer Subsystem
    CSS     	Control Stick Steering
    CSS     	Core Segment Simulator
    CSSA		Coarse Sun Sensor Assembly
    CSSE    	Control System Simulation Equipment
    CST     	Central Standard Time
    CST     	Combined Systems Test
    CST     	Contract Supplemental Tooling
    CST     	Crew Station Trainer
    CST     	Crew Systems Trainer (One-G Trainer)
    CSTA    	Crew Software Training Aid
    CSTR    	Canister
    CSTS    	Cryogenic Storage and Transfer System
    CT      	Crawler Transporter
    CT      	Current Transformer
    CTA     	Computer Technology Associates (GSFC)
    CTA     	Controlled Thrust Assembly
    CTC     	Camera, Timing, and Control
    CTC     	Chief Test Conductor
    CTC	        Core Technical Capabilities
    CTE     	Central Timing Equipment
    CTI     	Critical Transportation Item
    CTIS    	Crawler Transporter Intercom System
    CTL     	Central or Control
    CTL     	Canoga Test Laboratory
    CTM     	Crystalline Transitional Material
    CTM     	Contract Technical Manager
    CTN     	Certification Test Network
    CTP     	Cyclic Time Processor
    CTP     	Communications Timing Procedure
    CTPD    	Crew Training and Procedures Division (JSC)
    CTR     	Contract Technical Representative
    CTRS    	Component Test Requirements Specifications
    CTS     	Canadian Technology Satellite
    CTS     	Communications and Tracking System
    CTS     	Computer Test Set
    CTS     	Computerized Training System
    CTSD    	Computer Test Sequences Document
    CTSD    	Coordinate Transformation System
    CTTB    	Checkout Techniques Test Bed
    CTU     	Central Timing Unit
    CTWT    	Counterweight
    CU      	Control Unit
    cu      	Cubic
    CUB     	Commonality Usage Board
    CUC     	Computer Usage Control
    CUDS    	Cumulative Data Statistics
    CUE     	Common Usage Equipment
    CUF     	Cross Utilization File
    CUIL    	Common Usage Item List
    CUM     	Cumulative
    CUP     	Commonality Usage Proposal
    CV      	Check Valve
    CV      	Coefficient of Variation
    CV      	Deployable Payloads Operation (KSC CO Dir.)
    CV      	Expendable Vehicles Operations (KSC Directorate)
    CVAD    	Converter, Voltage, ac to dc
    CVAS    	Configuration Verification Accounting System
    CVDA    	Converter, Voltage Discrete, ac
    CVE     	Complete Vehicle Erector
    CVM     	Control Valve Module
    CVR     	Change Verification Record
    CVR     	Configuration Verification Review
    CVRD    	Converter, Variable Resistance, to dc Voltage
    CVT     	Communications Vector Table
    CVT     	Concept Verification Testing
    CW      	Clockwise
    CW      	Command Word
    CW      	Continuous Wave
    CWA     	Caution and Warning Annunciator
    CWA     	Clean Work Area
    CWA     	Controlled Work Area
    CWE     	Caution and Warning Electronics
    CWEA    	Caution and Warning Electronic Assembly
    CWEU    	Caution and Warning Electronics Unit
    CWFSP   	Caution and Warning/Fire Suppression Panel
    CWG     	Constant Wear Garment
    CWLM    	Caution and Warning Limit Module
    CWS     	Caution and Warning Status
    CWS     	Caution and Warning System
    CWSU    	Caution and Warning Status Unit
    CWSU    	Condensate Water Servicing Unit
    CX      	Color Exterior Film
    CY      	Calendar Year
    CY      	Cycle
    CYL     	Cylinder
    
    D
    
    D       Deck
    D       Deliver (Delivery)
    D       Delta
    D       Down
    D       Drag
    D&C     Display and Control (C&D preferred)
    D&CS    Display and Controls Subsystem
    D&O     Description and Operations
    D&P     Drain and Purge
    D&PD    Definition and Preliminary Design
    D&PS    Design and Performance Specification
    D&R     Definition and Requirement
    D/A     Digital to Analog
    D/C     Displays/Controls
    D/L     Data Link
    D/L     Deorbit/Landing
    D/L     Downlink
    D/L     Downlist
    D/S     Downstream
    D/VD    Data/Voice Data
    DA      Data Acquisition
    DA      Deployment Assembly
    DA      Distribution Assembly
    DA      Double Amplitude
    DA&D    Data Acquisition and Distribution
    DAAWG   Disability Awareness and Action Working Group
    DAB     Data Acquisition Bus
    DABS    Discrete Address Beacon System
    DAC     Data Acquisition and Control
    DAC     Data Acquisition Camera
    DAC     Digital to Analog Converter
    DAC     Digital to Analytical Conversion
    DACB    Data Acquisition and Control Buffer
    DACBU   Data Acquisition and Control Buffer Unit
    DACS    Data Acquisition and Control System
    DACS    Digital Acquisition and Control System
    DACT    Disposable Absorption Collection Trunk
    DADE    Data Acquisition and Decommutation Equipment
    DADS    Dual Air Density Satellite
    DAE     Data Acquisition Equipment
    DAF     Data Acquisition Facility
    DAF     Data Analysis Facility
    DAFT    Data Acquisition Frequency Table
    DAIS    Data Avionics Information System
    DAIU    Docked Audio Interface Unit
    DAL     Data Accession List
    DAL     Data Acquisition List
    DAL     Data Aided Loop
    DAM     Double Aluminized Mylar
    DAM     Driver Amplifier Module
    DAP     Data Acquisition Plan
    DAP	Data Analysis and Presentation
    DAP     Digital Autopilot
    DAR     Data Aided Receiver
    DAR     Deviation Approval Request
    DAR     Digital Autopilot Requirements
    DAR     Drawing Analysis Record
    DARPA   Defense Advanced Research Projects Agency
    DARS    Data Acquisition and Reduction System
    DART    Days Away, Restricted and Transferred
    DART	Demonstration of Autonomous Rendezvous Technology
    DARTS   Digital Automated Radar Tracking System
    DAS     Data Acquisition System
    DAS     Data Analysis Station
    DAS     Digital Address System
    DAS     Digital Avionics System
    DAS     Documentation Accountability Sheet
    DASA    Dual Aerosurface Servo Amplifier
    DATE    Dynamics, Acoustics, and Thermal Environment
    DAU     Data Acquisition Unit
    DAU     Digital Adapter Unit
    DAV     Data Available
    DAVL    Data Available-Low
    DB      Data Base
    DB      Data Bus
    DB      Deadband
    DB      Design Baseline
    DB      Distribution Box
    DB      Dry Bulb
    dB      Decibel
    DBC     Data Bus Control
    DBC     Data Bus Coupler
    DBCI    DB with Respect to a Circular Polarized Antenna
    DBE     Data Bus Element
    DBFN    Data Bus File Number
    DBFN    Data Base File Number
    DBG     Data Bus Group
    DBL     Double
    DBGMP   Data Bus Generation and Maintenance Package
    DBIA    Data Bus Interface Adapter
    DBIA    Data Bus Isolation Amplifier
    DBIU    Data Bus Interface Unit
    DBS     Data Base System
    dBM     Decibels Referred to 1 Milliwatt
    DBN     Data Bus Network
    DBP     Design Baseline Program
    DBRN    Data Bank Release Notice
    DBM     Data Base Management
    DBW     Data Bus Wire
    dBW     Decibels Referred to 1 Watt
    DBUR    Data Bank Update Request
    DBIA    Data Bus Isolation Amplifier
    DBN     Data Bus Network
    DC      Data Coordinator
    DC      Development-Center
    DC      Display Coupler
    dc      Direct Current
    DCA     Defense Communication Agency
    DCA     Design Change Authorization
    DCA     Digital Command Assembly
    DCA     Distribution Control Agency
    DCAA    Defense Contract Audit Agency
    DCAR    Design Corrective Action Report
    DCAS    Data Collection and Analysis System
    DCAS    Defense Contract Administration Services
    DCC     Data Computation Complex
    DCC     Document Control Center
    DCCU    Digital Command and Control Unit
    DCCU    Digital Communications and Control Unit
    DCCU    Display Computer Control Unit
    DCE	Drop Combustion Experiment
    DCIB    Data Communication Input Buffer
    DCIM/DSCIM  Display System Computer Input Multiplexer
    DCIU    Digital Control and Interface Unit
    DCKNG   Docking
    DCL     Document Change List
    DCM     Direction Cosine Matrix
    DCM     DECOM Control Memory
    DCM     Display and Control Module
    DCMB    Development Configuration Management Board
    DCN     Design Change Notice
    DCN     Document Change  Notice
    DCN     Drawing Change Notice
    DCNP    Document Change Notice Proposal
    DCO     Detailed Checkout
    DCOP    Detailed Checkout Procedures
    DCOP    Displays, Controls, and Operations Procedures
    DCP     Data Collection Platform
    DCP     Depot Condemnation Percent
    DCP     DEU Control Program
    DCP     Development Cost Plan
    DCPEI   DEU Control Program End Item
    DCR     Design Change Request
    DCR     Design Certification Review
    DCR     Document Change Record (or Review)
    DCR     Design Concern Report
    DCS     Data Communication System
    DCS     Data Control System
    DCS     Design Communication System
    DCS     Design Criteria Specification
    DCS     Detail Checkout Specification(s)
    DCS     Digital Command System (Subsystem)
    DCS     Display and Control System
    DCS     Document Control System
    DCS     Dual Checkout Station
    DCSI    Data and Control Signal Interface
    DCSP    Digital Control Signal Processor
    DCSU    Digital Computer Switching Unit
    DCU     Digital Computer Unit
    DCU     Display and Control Unit
    DCV     Direct Current Volts
    DD      Data Depository
    DD      Mechanical and Facilities Engineering (KSC DE Dir.)
    DD      Directives Documentation
    DD      Dedicated Displays
    DD      Data Display
    DD      Decoder Driver
    DD&CS   Dedicated Display and Control Subsystem
    DD/HH:MM:SS  Day/Hour:Minute:Second
    DDA     Digital Differential Analyzer
    DDA     ICD Departure Authorization
    DDAS    Digital Data Acquisition System
    DDC     Defense Documentation Center
    DDC     Data Distribution Center
    DDC     Digital Data Cell
    DDCU    Dc to DC Converter Unit
    DDD     Display Decoder Drive
    DDD     Design Definition Document
    DDDL    Digital Data Downlink
    DDDU    Digital Decoder Driver Unit
    DDI     Dedicated Display Indicator
    DDI     Discrete Data input
    DDI     Discrete Digital Input
    DDIS    Data Depository Index System
    DDL     Data Downlink
    DDM     Data Display Module
    DDM     Data Display Monitoring
    DDM     Discrete Data Management
    DDMS    DOD Manager for Space Shuttle Support
    DDO     Discrete Digital Output
    DDP     Design Development Plan
    DDP     Digital Data Processing (Processor)
    DDPC    Digital Data Processing Center (Complex)
    DDPF    Dedicated Display Processing Function
    DDPS    Digital Data Processing System
    DDR     Data Discrepancy Report
    DDR     Design Development Record
    DDR     Detail Design Review
    DDS     Documentation Distribution System
    DDS     Data Display System
    DDS     Detailed Design Specification
    DDT&E   Design, Development, Test, and Engineering/Evaluation
    DDT&E   Design, Development, Test, and Evaluation
    DDTF    Dynamic Docking Test Facility
    DDTS    Dynamic Docking Test System
    DDU     Decommutator Distribution Unit
    DDU     Data Display Unit
    DDU     Display Driver Unit
    DE      Design Engineering (KSC Dir.)
    DE      Doppler Extractor
    DE      Dynamics Explorer
    DEA     Deployed electronics assembly
    DEACT   Deactivate
    DEC     Declination
    DECL    Direct Energy Conversion Laboratory (JSC)
    DECOM   Decommutate, Decommutator
    DECR    Decrease
    DECS    Civil Engineering Office at Vandenberg
    DECU    Data Exchange Control Unit
    DED     Dedicate, Dedicated
    DEDA    Data Entry and Display Assembly
    DEE     Digital Events Evaluator
    DEF     Definition
    DEFL    Deflect
    DEG     Degree
    DEI     Design Engineering Identification
    DEIS    Design Engineering Inspection Simulation
    DEIS    Design Evaluation Inspection Simulator
    DEL     Deliver, Delivery
    DEL     Deorbit, Entry, and Landing
    DELTA-T Difference in Temperature
    DEMOD   Demodulate, Demodulator
    DEMUX   Demultiplexer
    DEORB   Deorbit
    DEPL    Deploy
    DEPRESS Depressurize
    DEPT    Department
    DER     Drawing Error Report
    DERIGID Derigidize
    DES     Data Exchange System
    DES     Descend, Descent
    DESAT   Desaturated
    DESC    Descent
    DESIG   Designate
    DESPOT  Design Performance Optimization
    DEST    Destination
    DET     Detent
    DET     Detail
    DETN    Detection
    DETR    Detector
    DEU     Display Electronic(s) Unit
    DEV     Develop, Development
    DEVN    Deviation
    DEW     Distant Early Warning
    DF      Development Flight
    DF      Development-Forward
    DF      Direction Finder (Finding)
    DF      Disassembly Facility
    DF      Display Functions
    DF-SPE-A  Shuttle Project Engineering Office
    DFCS    Digital Flight Control Software (System)
    DFE     Data Flow Engineer
    DFE     Direction Finding Equipment
    DFG     Display Format Generator
    DFI     Development Flight Instrumentation
    DFR     Defrost
    DFRC    Hugh L. Dryden Flight Research Center
    DFRF    Dryden Flight Research Facility
    DFRN    Differential
    DFRN PRESS  Differential Pressure
    DFS     Directional Finding System
    DFS     Dynamic Flight Simulator
    DFVLR   Deutsche Forschungs-und Versuchsanstalt Luft-und Raumfahrt
            Federal German Aerospace Research Establishment
    DG      Display Generator
    DH      Decision Height
    DHA     Design Hazards Analysis
    DHE     Data Handling Electronics
    DHS     Discrete Horizon Sensor
    DI      Data Integrator
    DI      Development Integration
    DI      Discrete Input
    DI      Display Interface
    DI      Display Interface Processor (Software Functional Element)
    DIA     Diameter
    DIAG    Diagonal
    DIAGN   Diagnose
    DIDS    Defense Integrated Data System
    DIF     Difference
    DIF     Discrete Increment Filter
    DIFF    Differential
    DIGI    Digital
    DIH     Discrete Input High
    DIL     Deliverable Items List
    DIL     Discrete Input Low
    DIM     Design Interface Meeting
    DIMEN   Dimension
    DIP     Designated Inspection Point
    DIP     Display Input Processor
    DIP     Display Interface Processing (Processor)
    DIPEC   Defense Industrial Plant Equipment Center
    DIPL    Display Initial Program Load
    DIR     Direct
    DIR     Document Information Record
    DIS     Documentation Index System
    DIS     Disagree
    DISAP   Disapproved
    DISASSY Disassembly
    DISC    Discone
    DISC    Disconnect
    DISC    Discrete
    DISCH   Discharge
    DISENG  Disengage
    DISP    Dispenser
    DISP    Display
    DIST    Distribution
    DIT     Dynamic Integrated Test
    DIU     Data Interface Unit
    DIU     Digital Interface Unit
    DIV     Division
    DIT     Data ID Table
    DIT     Dynamic Integrated Test
    DISTR   Distributor
    DK      Deck
    DK      Display/Keyboard
    DK      Docking
    DL      Development-Left
    DL      Downlink
    DL      Electronics Engineering (KSC DE Dir.)
    DLAT    Destructive Lot Acceptance Testing
    DLC     Direct Lift Control
    DLS     Dynamic Load Simulator
    DLSC    Defense Logistics Service Center
    DLSM    Data Link Summary Message
    DLTR    Data Link Terminal Repeater
    DLTR    Data Link Transmission Repeater
    DLY     Delay
    DM      Data Manager
    DM      Development Motor
    DM      Developmental Instrumentation MDM-Mid
    DM      Disassembly Manual
    DM      Docking Mechanism
    DM      Document, Documentation
    DMA     Direct Memory Access
    DMA     Direct Memory Address
    DMC     Data Management Computer
    DMC     Direct Maintenance Cost
    DMC     Drive Motor Assembly
    DMCF    Deservicing, Maintenance, and Checkout Facility
    DMD     Dextrous Manipulator Demonstration
    DME     Distance Measuring Equipment
    DMG     Data Management Group
    DMIA    Dual Multiplexer Interface Adapter
    DMIS    Data Management Information System
    DML     Developmental Instrumentation MDM-Left
    DMON    Discrete Monitoring
    DMP     Deployable Maintenance Platform
    DMP     DEU Message Processor
    DMP     Dump
    DMR     Developmental Instrumentation MDM-Right
    DMS     Data Management System
    DMS     Docking Mechanism System (Subsystem)
    DMS     Docking Module Subsystem
    DMS     Dynamic Motion Simulator
    DMSS    Data Management System Simulator (CVT)
    DN      Discrepancy Notice
    DN      Down
    DNA     Does Not Apply
    DNLK    Downlink (D/L preferred)
    DNLT    Downlist
    DNO     Descending Node Orbit
    DNP     Dynamic Nuclear Polarization
    DO      Discrete Output
    DOA     Department of Agriculture
    DOC     Department of Commerce
    DOC     Document, Documentation
    DOD     Department of Defense
    DOD-STP Department of Defense-Standard Satellite
    DODD    Department of Defense Directive
    DOE     Department of Energy
    DOF     Degree-of-Freedom
    DOF     Direction of Flight
    DOH     Discrete Output High
    DOI     Descent Orbit Insertion
    DOL     Department of Labor
    DOL     Discrete Output Low
    DOMSAT  Domestic Satellite
    DOP     Diver Operated Plug
    DOS     Disk Operating System
    DOSIM   Dosimeter
    DOT     Department of Transportation
    DOT     Deployment Operations Team
    DOT/CIAP  DOT Climatic Impact Assessment Program
    DOY     Day of Year
    DP      Data Processing
    DP      Delayed Procurement
    DP      Deployable Payload
    DP      Design Proof
    DP      Development Phase
    DP      Differential Pressure
    DP      Double Pole
    DP      Double Precision
    DP&S    Data Processing and Software
    DP&SS   Data Processing and Software Subsystem
    DP/DT   Delta Pressure/Delta Time
    DPA     Data Processing Assembly
    DPAF	Dual Payload Attachment Fitting 
    DPI     Detail Program Interrelationships
    DPLR    Doppler
    DPM     Dual Port Memory
    DPNL    Distribution Panel
    DPP     Deployment Pointing Panels
    DPR     Definition Phase Review
    DPS     Data Processing and Software
    DPS     Data Processing Software System
    DPS     Data Processing System (Subsystern)
    DPT     Design Proof Test
    DPY     Deploy
    DR      Dead Reckoning
    DR      Design Review
    DR      Development-Right
    DR      Discrepancy Report
    DR      Discrete Register
    DR      Dispatch Reliability
    DR      Disposition Record
    DR      Door
    DR      Drive
    DR&A    Data Requirements and Analysis
    DRA     Data Release Authorization
    DRB     Design Requirements Baseline
    DRB     Design Review Board
    DRC     Data Reduction Center
    DRC     Discrete Rate Command
    DRD     Data Requirement Description
    DRD     Data Requirements Document
    DRD     Detailed Requirements Document
    DRD     Document Requirement Description
    DRF     Data Request Form
    DRF     Digital, Radio Frequency
    DRF     Documentation Requisition Form
    DRG     Digital Ranging Generator
    DRI     Data Rate Indicator
    DRIRU   Dry Rotor Inertial Reference Unit
    DRK     Display Request Keyboard
    DRL     Data Requirements List
    DRL     Document Requirements List
    DRM     Data Records Management
    DRM     Design Reference Mission
    DRM     Drawing Requirements Manual
    DRN     Drain
    DRO     Document Release Order
    DROG    Drogue
    DRR     Data Recorder/Reproducer
    DRR     Design Requirements Review
    DRS     Data Relay Satellite
    DRS     Data Relay Station
    DRS     Digital Range Safety
    DRSS    Discrepancy Report Squawk Sheet
    DRT     Design Reference Timeline
    DRTT	Discrepancy Report Tracking Tool
    DRUC    Disposition Record Unsatisfactory Condition
    DS      Data Storage
    DS&R    Data Storage and Retrieval
    DSA     Defense Supply Agency
    DSAD    Data Systems and Analysis Directorate (JSC)
    DSB     Document Status Bulletin
    DSB     Double Side Band
    DSC     Data Separator Card
    DSC     Dedicated Signal Conditioner
    DSN     Deep-Space Network
    DTO     Development Test Objective
    DTP     Detail Test Plan
    DTPR    Detailed Test Procedures
    DTRD    Development Test Requirements Document
    DTS     Data Transmission System
    DTS     Data Transfer System
    DU      Display Unit
    DUA     Digital Uplink Assembly
    DUC     Digital Uplink Command
    DUM     Dummy
    DUPLX   Duplex
    DUPLXR  Duplexer
    DUR     Duration
    DV      Designated Verification
    DV      Designee for Verification
    DV      Differential Velocity
    DVD     Delta Velocity Display
    DVM     Digital Voltmeter
    DVS     Design Verification Specification
    DVS     Digital Voice System
    DVT     Design Verification Testing
    DVT     Development Verification Test
    DW      Data Word
    DWG     Drawing
    DWI     Data Word In
    DWS     Disaster Warning Satellite
    DWV     Dielectric Withstanding Voltage
    DY      Deputy Director (KSC Directorate)
    DYN     Dynamic
    DXS     Diffuse X-Ray Spectrometer
    
    E
    
    E       East
    E       Elevation Angle
    E       Engine
    E       Exempt (From Traceability)
    E&D     Engineering and Development
    E&D     Engineering and Development Directorate (JSC)
    E&I     Electrical and Instrumentation
    E&OO    Engineering and Operations Office
    E-E     End-to-End
    E-MUX   Electrical Multiplex
    E-P     Electron/Proton
    E/C     Encoder/Coupler
    E/L     Entry/Landing
    E/M     Engineering Model
    E/O     Engineering/Operations
    E/O-IMS E/O-Information Management System
    E/W     Energy to Weight Ratio
    E/W     Energy Over Weight
    EA      Each
    EA      Electronic Assembly
    EA      Elevation Angle
    EAC     Energy Absorbing Capacity
    EAC     Estimate at Completion
    EAC     Experiment Apparatus Container
    EAD     Electrically Alterable Device
    EADI    Electronic Attitude Director Indicator
    EADS    Engineering Analysis and Data System
    EAFB    Edwards Air Force Base
    EAFB    Eglin Air Force Base
    EAFB    Ellington Air Force Base
    EAM     Electrical Accounting Machine
    EAP     Educator Astronaut Program
    EAP     Employee Assistance Program
    EAR     Engineering Analysis Report
    EAS     Equivalent Air Speed
    EAT     Environmental Acceptance Test
    EB      Electronic Beam
    EB      Emergency Box
    EBC     Emulated Buffer Computer
    EBCDC   Extended Binary Coded Decimal
    EBD     Eyeballs Down (+GZ)
    EBI     Eyeballs In (+GX)
    EBL     Eyeballs Left (+GY)
    EBO     Eyeballs Out (-GX)
    EBR     Eyeballs Right (-GY)
    EBS     Emergency Breathing Subsystem
    EBU     Eyeballs Up (-GZ)
    EBW     Electron Beam Welding
    EBW     Exploding Bridge Wire
    EC      Element Contractor
    EC      Engine Control
    EC      Engine Cutoff
    EC      Essentiality Code
    EC      Events Controller
    EC      Events Coupler
    EC      Experiment Computer
    ECA     Electronics Control Assembly
    ECA     Engineering Change Analysis
    ECA     Epoxy Curing Agent
    ECAS    Experiment Computer Application Software
    ECB     Engineering Change Board
    ECB     Event Control Block
    ECB     Events Control Buffer
    ECC     Engineering Change Control
    ECC     Engineering Critical Component
    ECCB    Engineering Change Control Board
    ECD     Engineering Control Drawing
    ECD     Estimated Completion Date
    ECEP    Experiment Checkout Equipment Processor
    ECF     Element Charge Factor
    ECF     Equivalency Capability File
    ECG     Electrocardiogram
    ECG     Electrocardiograph
    ECI     Earth Centered Inertia (inertials)
    ECIO    Experiment Computer Input/Output
    ECL     Entry Closed Loop
    ECLS    Environmental Control and Life Support
    ECLSS   Environmental Control and Life Support System (Subsystem)
    ECN     Engineering Change Notice
    ECO     Engine Combustion
    ECO     Engine Cutoff
    ECO     Engineering Change Order
    ECOS    Experiment Computer Operating System
    ECP     Engineering Change Program
    ECP     Engineering Change Proposal
    ECP     Engineering Control Proposal
    ECP     Explicitly Coded Program
    ECR     Engineering Change Request
    ECRA    Engineering Change Request/Authorization
    ECS     Engine Control System
    ECS     Environmental Control System (Subsystem)
    ECU     Electrical Control Unit
    ECU     Electronic Coupling Unit
    ECU     Environmental Control Unit
    ECU	Experiment Control Unit
    ED      Edge Distance
    ED      Edit
    ED      Engineering Directive
    ED      Explosive Device
    EDA     Electronic Display Assembly
    EDA     Elevation Drive Assembly
    EDAX	Compositional Analysis
    EDB     Environmental Data Book
    EDC     Engineering Design Change
    EDC(M)  Electrochemical Depolarized CO2 (Module)
    EDCP    Engineering Design Change Proposal
    EDDR    Electron Dipole-Dipole Reservoir
    EDF     Engineering Data File
    EDLN    Engineering Development Logic Network
    EDM	Electro-Discharge Machining
    EDMS	Enterprise Document Management System
    EDNi	Electro-Deposit Nickel
    EDO	Extended Duration Orbiter
    EDP     Electonic Data Processing
    EDP	Embedded Data Processor
    EDPE    Electronic Data Processing Equipment
    EDPM    Electronic Data Processing Machine
    EDR     Engineering Design Review
    EDS     Electrical Distribution System
    EDS     Emergency Detection System
    EDS     Explosive Device System
    EDT     Eastern Daylight Time
    EDU     Engineering Development Unit
    EDV     Electronic Depressurizing Valve
    EDW     Edwards (TACAN Station)
    EDW     Edwards Air Force Base, CA (Deorb OPT site)
    EE      End Effector
    EEC	Extendible Exit Cone
    EECOM   Electrical, Environmental, and Communications
    EECOM   Electrical, Environmental, Consumables, and Mechanical Systems (MPSR)
    EED     Electro (Electrical) Explosive Device
    EED     Electroexplosive device
    EEE     Electronic, Electrical, Electromechanical
    EEEU    End Effector Electronics Unit
    EEG     Electroencephalogram
    EEH     EMU Electrical Harness
    EEIS    End-to-End Information System
    EEL     Electrical Equipment List
    EEM     Earth Entry Module
    EENT    Eye, Ear, Nose, and Throat
    EES     Ejection Escape Suit
    EES     Emergency Ejection Suits
    EES     Escape Ejection Suit
    EET     Entry Elapsed Time
    EETB    Electronic Electrical Termination Building
    EEVT    Electrophoresis Equipment Verification Test
    EFA     Experiment Flight Applications
    EFCS    Earth Fixed Coordinate System
    EFF     Efficiency
    EFFGRO  Efficient Growth (Computer Program)
    EFP     ESA Furnished Property
    EFTO    Encrypted for Transmission Only
    EG      Entry Guidance
    EGA     Evolved Gas Analysis
    EGC     Experiments Ground Computer
    EGF     Electrical, Grapple Fixture
    EGIL    Electrical, General Instrumentation, and Lighting Engineer
    EGRET   Energetic Gamma Ray Explorer Telescope
    EGRS    Egress
    EGSE    Electrical Ground Support Equipment
    EGT     Elapsed Ground Time
    EGT     Estimated Ground Time
    EGT     Exhaust Gas Temperature
    EGUN    Fast Pulse Electron Gun
    EH/M    Extension Hose/Mouthpiece
    EHC     Electrical Heating Control
    EHF     Extremely High Frequency
    EHOT    External Hydrogen/Oxygen Tank
    EHP     Effective Horsepower
    EHP     Electrical Horsepower
    EHR     Earned Hour Ratio
    EHS     Enhanced HOSC System
    EHS     Environmental Health Services
    EHX     Experiment Dedicated Heat Exchanger
    EI      Electromagnetic Interference
    EI      Electronic Interface
    EI      End Item
    EI      Engineering Instruction
    EI      Entry Interface
    EI      Environmental Impact
    EIA     Electrical Industries Association
    EIASN   End Item Assembly Sequence Number
    EIC     Experimental Intercom
    EID     End Item Documentation
    EIDP    End Item Data Package
    EIFA    Element Interface Functional Analysis
    EIR     Environmental Impact Report
    EIRP    Effective Isotropic Radiated Power
    EIS     Electrical Integration System
    EIS     End Item Specification
    EIS     Environmental Impact Statement
    EIS     Extended Instruction Set
    EIT     Entry Interface Time
    EIU     Engine Interface Unit
    EIVT    Electrical and Instrumentation Verification Test
    EIVT    Electrical Interface Verification Test
    EIVT    Electronic Installation Verification Test
    EJN     Ejection
    EKG     Electrocardiogram (Record)
    EKG     Electrocardiograph (Instrument)
    EL      Elastic Limit
    EL      Electroluminescent
    EL      Elevate
    EL      Elevation Angle
    EL      Equipment List
    EL MECH Electromechanical
    ELACS   Extended Life Attitude Control System
    ELB     Elbow
    ELDISC  Electrical Disconnect
    ELDV    Electrically Operated Depressurization Valve
    ELEC    Electronic
    ELEC    Electric
    ELECT   Electrical
    ELECTR  Electronics
    ELEV    Elevon
    ELF     Extremely Low Frequency (1 Hz to 3 kHz)
    ELINT   Electromagnetic Intelligence
    ELMCH   Electromechanical
    ELMS    Elements
    ELMS    Elastic Loop Mobility System
    ELS     Earth Landing System (Subsystem)
    ELS     Eastern Launch Site
    ELS     Elevon Load System
    ELS     Emergency Landing Site
    ELS     Energy Loss Spectroscopy
    ELSC    Earth Landing Sequence Controller
    ELSS    Emergency Life Support System
    ELT     Emergency Locator Transmitter
    ELV     Earth Launch Vehicle
    ELV     Electrically Operated Valve
    ELV     Expendable Launch Vehicle
    ELVIS	Expendable Launch Vehicle Integrated Support
    ELVN    Eleven
    EM      Electromagnetic
    EM      Emergency
    EM      Engineering Model
    EM      Exception Monitor
    EMA     Electromagnetic Analysis
    EMC     Electromagnetic Compatibility
    EMCC    Emergency Mission Control Center
    EMCD    Electro-Mechanical Control Diagram
    EMCI    Engineering Model Configuration Inspection
    EMD     Entry Monitor Display
    EMEC    Electromagnetic Effects Capability
    EMEC    Electromagnetic Effects Compatibility
    EMER    Emergency
    EMES    Electriral, Mechanical, and Environmental Systems
    EMF     Electromagnetic Force
    EMF     Electromotive Force
    EMG     Electromyograph(gram)
    EMG     Surface Electromyograms
    EMI     Electromagnetic Interference
    EMIS    Emission
    EMK     Emergency Medical Kit
    EMK     Emergency medical kit
    EML     Electromagnetic Laboratory
    EMN     Engineering Management Network
    EMON    Exception Monitoring
    EMP     Electromagnetic Pulse
    EMP     Equipment Mounting Plate
    EMPGS   Electrical/Mechanical Power Generation Subsystem
    EMR     Engine Mixture Ratio
    EMRL    Equipment Maintenance Requirements List
    EMS     Electromagnetic Susceptibility
    EMS     Engineering Master Schedule
    EMS	Engineering Modeling System
    EMS     Entry Monitor Subsystem
    EMS     Entry Monitoring System
    EMSF	External Maintenance and Servicing Facility
    EMSS    Electromagnetic Servoactuator System
    EMT     Electromechanical Test
    EMU     Engineering Model Unit
    EMU     Extended Memory Unit
    EMU     Extravehicular Mobility Unit
    EMU-TV  Extravehicular Mobility Unit - Television
    E-MUX	Electrical Multiplex
    ENA     Enable
    ENC     Encode
    ENCD    Encode
    ENCL    Enclose
    END EFF End Effector
    ENDF    Evaluated Neutron Data File
    ENG     Engine, Engineer
    ENG     Electronystagnogram
    ENGR    Engineer
    ENGRG   Engineering
    ENIAC   Electronic Numerical Integrator and Computer
    ENT     Entry
    ENVIR   Environment, Environmental
    EO      Earth Observation
    EO      Earth Orbit
    EO      Engineering Order
    EO      Engine Out
    EO      Equal Opportunity Program Office (KSC Directorate)
    EOC     End of Contract
    EOC     Engine Order Capability
    EOC     Engine-out Capability
    EOD     Entry on Duty
    EOC	EOS Operations Center
    EOD     Environmental Observation Division
    EOD     Estimated on Dock
    EOD     Explosive Ordnance Disposal
    EODB    End of Data Block
    EOF     End of File
    EOG     Electroculogram
    EOHT    External Oxygen and Hydrogen Tanks
    EOI     Earth Orbit Insertion
    EOL     End of Line
    EOM	Earth Observation Mission
    EOM     End of Message
    EOM     End of Mission
    EOM	End of Month
    EOM     Engineering Operations Manual
    EOM     Equations of Motion
    EOMF    End of Minor Frame
    EOO	Equal Opportunity Office
    EOP     Earth and Ocean Physics
    EOP     Emergency Oxygen Pack
    EOP     Experiments of Opportunity
    EOPAP   Earth and Ocean Physics Application Program
    EOPO    Equal Opportunity Program Office
    EOR     Earth Orbit Rendezvous
    EOS     Earth Observation Satellite
    EOS	Earth Observing System
    EOS     Earth Orbit Shuttle
    EOS     Emergency Oxygen Supply
    EOS     Emergency Oxygen System
    EOS     Extended Operating System
    EOSDIS	EOS Data and Information System
    EOT     End of Tape
    EOT     End of Transmission
    EOW     Energy over Weight
    EP      Elbow Pitch
    EP      Electrical Power
    EP      Environmental Protective Plan
    EP      Equivalent Person
    EPA     Environmental Protection Agency
    EPAR	External Tank Project Assessment Review
    EPC     Error Protection Code
    EPC     External Power Contractor
    EPCDC   Electrical Power Conditioning, Distribution, and Control
    EPD     Electrical Power Distribution
    EPD     Emergency Procedures Document
    EPDB    Electrical Power Data Box
    EPDB    Electrical Power Distribution Box
    EPDB    Experiment Power Distribution Box
    EPDC    Electrical Power Distribution and Control
    EPDCS   Electrical Power Distribution and Control System (Subsystem)
    EPDM	Ethylene Propylene Diene Monomer
    EPDS    Electrical Power and Distribution Subsystem
    EPDS    Electrical Power Distribution Subsystem
    EPDS    Electrical Power Distribution System
    EPDS	Experiment Power and Data System
    EPDU    Electrical Power Distribution Unit
    EPE	Energetic Particle Explorer
    EPG     Electrical Power Generator
    EPL     Electrical Power Level
    EPL     Electronic, Electrical, and Electromechanical Parts List
    EPL     Emergency Power Level
    EPMS    Engineering Performance Management System
    EPO     Element Project Office
    EPOC    External Payload Operations Center
    EPPS    Electrical Power/Pyro Sequential System
    EPR     Engine Pressure Ratio
    EPRN    Emergency Program Release Notice
    EPROM   Erasable Programmable Read Only Memory
    EPS     Electrical Power System (Subsystem)
    EPS     Evaluation Planning System
    EPS     Experimental Power Supply
    EPSP    Experiment Power Switching Panel
    EPT     Emergency Procedure Trainer
    EPT     Ethylene Propylene Terpolymer
    EPTU    Events per Time Unit
    EPWG    Environmental Projects Working Group
    EQ      Equivalent
    EQE     Event Queue Element
    EQL     Equal
    EQUIP   Equipment
    EQUIV   Equivalent
    ER      Explanation Report
    ERA     Electrical Replaceable Assembly
    ERA     Exabiology and Radiation Assembly
    ERAP    Earth Resources Aircraft Program
    ERB     Engineering Review Board
    ERBE    Earth Radiation Budget Experiment
    ERBE-NS ERBE Nonscanner
    ERBE-S	ERBE Scanner
    ERBS    Earth Radiation Budget Satellite
    ERC     Event Recorder
    ERCA    Electrochemically Regenerable CO2 Absorber
    ERD	Experiment Requirements Document
    EREP    Earth Resources Package
    ERG     Ergometer
    ERIP	Experiment Requirement and Implementation Plan
    ERL	Environmental Research Laboratory
    ERNO    'Entwicklungts Ring Nord' Organization, Space Division of European Consortium,
            VFW-Fokker-Mannheim, Germany (Spacelab Contractor)
    ERO     Engineering Release Operations
    EROS	Earth Resources Observation System
    ERP     Effected Radiative Power
    ERP     Effective Radiation Power
    ERP     Eye Reference Point
    ERPM    Engineering Requirements and Procedures Manual
    ERR     Error
    ERR CNTR Error Counter
    ERRC    Expendability/Recoverability/Repair Capability
    ERS     Earth Recovery Subsystem
    ERS     Element Rotation Stand
    ERS     Engineering Release System
    ERS     Entry and Recovery Simulation
    ERS-1	Earth Remote Sensing Satellite-1
    ERSI    Elastomeric Reusable Surface Insulation
    ERSIR   Earth Resources Shuttle Imaging Radar
    ERTS    Earth Resources Technology Satellite
    ERU     Earth Rate Unit
    ERV     Expiratory Reserve Volume
    ES	Electrical System
    ES	Equipment Section
    ES	Equipment Shelf
    ES      Escape System
    ES      Experiment Segment
    ESA     Engineering Supply Area
    ESA     Engineering Support Assembly
    ESA     European Space Agency
    ESA     Explosive Safe Area
    ESB     Essential Switching Box
    ESC	Engine Start Command
    ESC	Engineering Support Center
    ESC     Escape
    ESCA    Electron Spectroscopy for Chemical Analysis
    ESCU    Extended Service and Cooling Umbilical
    ESD	Electrostatic Discharge
    ESD     Emergency Shutdown	
    ESD     Experiment Systems Division
    ESDAC   European Space Data Center (Darmstadt, Germany)
    ESDIS	Earth Science Data and Information System
    ESDU    Event Storage and Distribution Unit
    ESE     Electrical Support Equipment
    ESE     Electronic Support Equipment
    ESE     EVA Support Equipment
    ESF     Explosive Safe Facility
    ESI     Electrical System Integration
    ESMC    Eastern Space and Missile Center (formerly AFETR), also ETR
    ESMOS	Earth Science Mission Operations and Systems
    ESO     Event Sequence Override
    ESOC    European Space Operations Center
    ESOW    Engineering Statement of Work
    ESP     Electroshock Protection
    ESP     Engine Service Platforms
    ESP     Experiment Sensing Platform
    ESP     External Stowage Platform
    ESPS    Experiment Segment Pallet Simulator
    ESR     Effective Sunrise
    ESR     Engineering Support Request
    ESRIN   European Space Research Institute
    ESRO    European Space Research Organization
    ESS     Effective Sunset
    ESS     Environmental Support System
    ESS     Equipment Support Section
    ESS     Essential
    ESS     Experiment Subsystem Simulator
    ESSA    Environmental Sciences Services Administration
    EST     Eastern Standard Time
    EST     Estimate(d)
    ESTA    Electronic System Test Equipment
    ESTA    Escape System Test Article
    ESTEC   European Space Research and Technology Center
    ESTEC   European Space Technology Center
    ESTL    Electronic Systems Test Laboratory
    ESV     Emergency Shutoff Valve
    ESVS    Escape Suit Ventilation System
    ESVS    Escape System Ventilation System
    ESW     Engine Status Word
    ET      Edge Thickness
    ET      Elapsed Time
    ET      Elevated Temperature
    ET      Event Timer
    ET      External Tank
    ET-SEP  External Tank Separation
    ETA     Environmental Test Article
    ETA     Estimated Time of Arrival
    ETA     Estimated Time to Acquisition
    ETA     Explosive Transfer Assembly
    ETA     External Tank Attachment
    ETB     Equipment Transfer Bag
    ETC     Earth Terrain Camera
    ETC     Estimate to Completion
    ETC     Greenbelt, Maryland (STDN Site)
    ETCO    Equipment Transfer/Change Order
    ETD     Electrical Terminal Distributor
    ETD     Estimated Turnover Date
    ETD     External Tank Door
    ETE     End-to-End
    ETI     Elapsed Time Indicator
    ETLOW   External Tank Lift-Off Weight
    ETM     Elapsed Time Meter
    ETP     Equipment Test Plan
    ETR     Eastern Test Range (ESME preferred)
    ETROD   Eastern Test Range Operations Directive
    ETS     Electrical Test Set
    ETS     Energy Transfer System
    ETS     External Tank System (Subsystem)
    ETSS    External Tank Separation Subsystem
    ETVA    External Tank Vent Arm
    EU      Electronic Unit
    EU      Engineering Units
    EU      Experimental Unit
    EUROCOMSATE  European Consortium Communications Satellite
    EUV     Extreme Ultraviolet
    EUVE    Extreme Ultraviolet Explorer
    EV      Electron Volts
    EV      Expendable Vehicles
    EV      Extravehicular
    EVA     Earned Value Analysis
    EVA     Earned Value Assessment
    EVA     Extravehicular Activity
    EVAL    Earth Viewing Applications Laboratory
    EVAL    Evaluate, Evaluation
    EVAP    Evaporator
    EVATA   Extravehicular Activity Translational Aid
    EVC     Extravehicular Communications
    EVCON   Events Control (Subsystem)
    EVCS    Extravehicular Communications System
    EVCU    Extravehicular Communications Umbilical
    EVD     External Visual Display
    EVF     Equipment Visibility File
    EVLSS   Extravehicular Life Support System
    EVM     Earth Viewing Module
    EVMS    Earned Value Management System
    EVMU    Extra Vehicular Mobility Unit
    EVO     Engineering Verification Order
    EVS     Equipment Visibility System
    EVS     Extravehicular Suit
    EVSC    Extravehicular Suit Communications
    EVSS    Extravehicular Space Suit
    EVSU    Extravehicular Space Unit
    EVT     Engineering Verification Test
    EVT     Extravehicular Transfer
    EVVA    Extravehicular Visor Assembly
    EWA     Estimated Warehouse Arrival
    EWE     Emergency Window Escape
    EWO     Engineering Work Order
    EWR     Engineering Work Request
    EX      Executive Management Office (KSC Directorate)
    EXC     Experiment Computer
    EXCH    Exchange
    EXEC    Execute
    EXH     Exhaust
    EXO     Experiment Operator (in Spacelab)
    EXP     Expand
    EXP     Experiment
    EXP     Exposure
    EXPEN   Expendable
    EXT     Experiment Terminal (Operator Console on Spacelab)
    EXT     Extension
    EXT     External
    EXTD    Extend
    EXTER   External
    EXTGH   Extinguish
    
    F
    
    F       Fahrenheit
    F       Failure
    F       Farad (SI Unit of Capacitance)
    F       Female
    F       Forward
    F       Front
    F&E     Facility and Environment
    F&S     Fire and Smoke Detection
    F/A     Failure Analysis
    F/A     Fuel-Air
    F/C     Fit Check
    F/C     Flight Controller
    F/C     Fuel Cells
    F/D     Fill/Drain
    F/E     Full/Empty
    F/F     Fill/Full, Full/Fill
    F/O     Fuel/Oxidizer Ratio
    F/R     Flared Rudder
    FA      Failure Analysis
    FA      Final Approach
    FA      Final Assembly
    FA      Flight Aft
    FA      Flight Critical Aft
    FA      Fully Automatic
    FA/COSI Final Assembly and Closeout System Installation
    FAA     False Alarm Avoidance
    FAA     Federal Aviation Administration
    FAB     Fabricate, Fabrication
    FAC     Facility
    FACI    First Article Configuration Inspection
    FACO    Fabrication and Acceptance Checkout
    FACO    Factory Acceptance Checkout
    FACO    Factory Assembly and Checkout
    FACO    Final Assembly Checkout
    FACS    Facilities Control
    FACS    Finance and Control System
    FACT    Flexible Automatic Circuit Tester
    FAD     Final Approach Display
    FAF     First Aerodynamic Flight
    FAGS    Federation for Astronomical and Geophysical Services
    FAIR    Fabrication, Assembly, and Inspection Record
    FAJ     Final Assembly Jig
    FAL     First Approach and Landing (Test)
    FAM     Familiarization
    FAMOS   Flight Acceleration Monitor Only System
    FAO     Flight Activities Officer
    FAP     Final Approach Plane
    FAR     Failure Analysis Report
    FAR     Federal Aviation Regulation
    FAR     Final Acceptance Review
    FAR     Flight Acceptance Review
    FAR-UV  Far Ultraviolet Camera
    FARC	Federal Archives and Records Center
    FASCOS  Flight Acceleration Safety Cutoff System
    FAT     Flight Attitude Table
    FAUST   Far Ultraviolet Space Telescope
    FAWG    Flight Assignment Working Group
    FAX     Facsimile Transmission
    FB      Feedback
    FB      Final Braking
    FBAS    Fixed Base Aft Station
    FBC     Fluidized-Bed Combustion
    FBCS    Fixed Base Crew Station (SMS)
    FBS     File Backup System
    FBS     Firefighters Breathing System
    FBS     Flare Buildup Study
    FBV     Field Base Visit
    FBV     Fuel Bleed Valve
    FC      Fit Check
    FC      Flight Computer
    FC      Flight Control
    FC      Flight Critical
    FC      Fuel Cell
    FC      Furnace Container
    FCA     Fluids Control Assembly
    FCA     Frequency Control Analysis
    FCA     Functional Compatibility Analysis
    FCA     Functional Configuration Audit
    FCAF    Flight Crew Accommodations Facility
    FCAP    Flight Control Applications Program
    FCC     Federal Communications Commission
    FCC     Flat Conductor Cable
    FCC     Flight Control Computer
    FCC     Flight Crew Compartment
    FCCP    Firm Contract Cost Proposal
    FCD     Flight Control Division (JSC)
    FCDB    Flight Control Data Bus
    FCE     Flight Control Equipment
    FCE     Flight Crew Equipment
    FCEF    Flight Crew Equipment Facility
    FCEI    Facility Contractor End Item
    FCF     First Captive Flight
    FCF     Flight Critical Forward
    FCF     Functional Check Flight
    FCFM    Flight Combustion Facility Monitor
    FCH     Flight Controllers Handbook
    FCHL    Flight Control Hydraulics Laboratory
    FCI     Flight Control Indicator
    FCI     Functional Configuration Identification
    FCIM    Flight Control Interface Module
    FCIP    Flight Cargo Implementation Plan
    FCIT    First Computer Interface Tester
    FCL     Freon Coolant Line
    FCL     Freon Coolant Loop
    FCMU    Foot Controlled Maneuvering Unit
    FCN     Function
    FCO     Final Checkout
    FCO     Functional Checkout
    FCOH    Flight Controllers Operational Handbook
    FCOS    Flight Computer Operating System (Orbiter)
    FCOS    Flight Control Operating System
    FCOS    Flight Control Operational Software
    FCP     Failure Correction Panel
    FCP     Firm Cost Proposal
    FCP     Flight Correction Proposal
    FCP     Fuel Cell Power (Plant)
    FCPS    Fuel Cell Power System (Subsystem)
    FCR     Final Configuration Review
    FCR     Flight Configuration Review
    FCR     Flight Control Room
    FCRA    Fecal Collection Receptacle Assembly
    FCRT    Flight Display CRT
    FCS     Fecal Containment System
    FCS     Federal Communications System
    FCS     Financial Control System
    FCS     Flight Control System (Subsystem)
    FCS     Flight Crew System
    FCSM    Flight Combustion Stability Monitor
    FCSS    Fuel Cell Servicing System
    FCT     Flight Control Team
    FCT     Flight Crew Trainer
    FCT     Fuel Cell Test
    FCTB    Flight Crew Training Building
    FCTF    Fuel Cell Test Facility
    FCTS    Flight Crew Trainer Simulator
    FCU     Fluid Checkout Unit
    FCW     Format Control Words
    FD      Fault Detection
    FD      Feed
    FD      Flight Day
    FD      Flight Deck
    FD      Flight Director
    FD      Freeze Dried
    FD      Function Designator
    FD WMR  Food Warmer
    FDA     Fault Detection and Annunciation
    FDA     Flight Deck Assembly (FDF)
    FDAI    Flight Director Attitude Indicator
    FDB     Fahrenheit Dry Bulb
    FDD	Flight Definition Document
    FDDB    Function Designator Data Base
    FDE	Fluid Dynamics Experiment
    FDF     Flight Data File
    FDF     Flight Dynamics Facility
    FDI     Failure Detector Indicator
    FDI     Fault Detection and Identification
    FDI     Fault Detection and Isolation
    FDIIR   Fault Detection, Isolation, Identification, and Recompensation
    FDIR    Fault Detection Identification/Isolation and Recovery/Recognition
    FDL     Flight Director Loop
    FDLN    Feedline
    FDM     Flight Data Manager
    FDM     Frequency Data Multiplexer
    FDM     Frequency Division Multiplexing
    FDMA	Full Diameter Motorized Door Assembly
    FDO     Fee Determination Official
    FDO     Flight Dynamics Officer
    FDOR    Flight Design Operations Review
    FDR     Final Design Review
    FDR     Flight Data Recorder
    FDR     Functional Design Review
    FDRD	Flight Definition and Requirements Document
    FDRI    Flight Director Rate Indicator
    FDS	Fire Detection and Suppression
    FDS     Flight Design and Scheduling
    FDS     Flight Design System
    FDS     Flight Dynamics Simulator
    FDS     Flight Dynamics Software/System
    FDS     Fluid Distribution System
    FDS     Functional Design Specifications
    FDSC    Flight Dynamics Simulation Complex
    FDSC    Flight Dynamics Situation Complex
    FDU     Fluid Distribution Unit
    FDX     Full Duplex
    FEA     Failure Effects Analysis
    FEA	Fluids Experiment Apparatus
    FEAT    Final Engineering Acceptance Test
    FEB     Forward Equipment Bay
    FEC     Field Engineering Change
    FEC     Forward Events Controller
    FED     Flight Events Demonstration
    FEDP    Facility and Equipment Design Plan
    FEGLI	Federal Employees Group Life Insurance
    FEID    Flight Equipment Interface Device
    FEID    Functional Engineering Interface Device
    FEM     Finite Element Method
    FEMCPL  Facilities and Envir. Measurement Comp. Parts List
    FEP	Flight Evaluation Plan
    FEP     Fluoro Ethel Propane
    FEP     Fluorinated Ethylene Propylene
    FEP     Front End Processor
    FERD    Facility and Equipment Requirements Document
    FERS	Federal Employees Retirement System
    FES     Flash Evaporator System
    FES     Flight Element Set
    FES     Fluid Experiment System
    FES/VCGS  Fluid Experiment System/Vapor Crystal Growth System
    FESL    Failure Effects Summary List
    FET     Field Effect Transistor
    FET     Flight Elapsed Time
    FEU     Flight Equivalent Unit
    FEW     Federally Employed Women
    FEWG    Flight Evaluation Working Group
    FF      Flight Forward
    FF      Flip Flop
    FF      Free Flight
    FFBD    Functional Flow Block Diagram
    FFC     Final Flight Certification
    FFD     Fixed Format Display
    FFD     Functional Flow Diagram
    FFM     Free-Flying (Experiment) Module
    FFP     Firmed Fixed Price
    FFTO    Free-Flying Teleoperator
    FGE	Fine Guidance Electronics
    FGS	Fine Guidance Sensors
    FGS	Fine Guidance System
    FGSE	Fine Guidance System Electronics	
    FH      Flex Hose
    FHC     Flight Half Coupling
    FHD     Fixed Head Disk
    FHF     First Horizontal Flight
    FHO     Failed Handover
    FHP     Fuel High Pressure
    FHS     Forward Heat Shield
    FHST	Fixed-Head Star Tracker
    FI      Fault Identification
    FI      Flight Instrumentation
    FI      Formal Inspection
    FIAR    Failure Investigation Action Report
    FID     Failure Identification
    FID     Flight Implementation Directive
    FIDO    Flight Dynamics Officer
    FIE     Flight Instrumentation Engineer
    FIFO    First In-First Out (High Speed Data Buffers)
    FIG     Figure
    FIIG    Federal Item Identification Guide
    FIL     Filament
    FILE    Future Identification and Location Experiment
    FIO     Furnished and Installed by Others
    FIPS	Federal Information Processing Standards
    FIR     Fuel Indicating Reading
    FIRST	Far-Infrared Space Telescope
    FIS     Facility Interface Sheets
    FIT     Fault Isolation Test
    FIT	First Computer Interface Tester
    FITH    Fire-in-the-Hole
    FIV     Fuel Isolation Valve
    FKB     Flight Display Keyboard
    FKF	Flight Kits Facility
    FL      Fail
    FL      Feed Lines
    FL      Flowline
    FL      Forward Link
    FL MECH Fluid Mechanical
    FLAP    Flight Application Software
    FLC     Federal Library Committee
    FLC     Forward Load Control
    FLCA    Forward Load Control Assembly
    FLD     Field
    FLEX    Flexible
    FLG     Flag
    FLG     Flange
    FLLK    Frustum Lifting Lug Kit
    FLMC    Florida Labor Management Conference
    FLN     Fuel Line
    FLOT    Flotation
    FLP     Flap
    FLPS    Flight Load Preparation System
    FLR     Flare
    FLR     Failure
    FLS     Flight Surgeon
    FLSC    Flexible Linear Shaped Charge
    FLT     Flight
    FLT     Floating
    FLTR    Filter
    FLTSATCOM  Fleet Satellite Communications
    FLUOR   Fluorescent
    FLW     Fellows (TACAN Station)
    FM      Failure Mechanics
    FM      Flight Model
    FM      Frequency Modulation (Modulated)
    FM      Furnace Module
    FM/FM   Frequency Modulation/Frequency Multiplexing
    FM/PM   Frequency Modulation/Phase Modulation
    FMA     Failure Mode Analysis
    FMAHTS  Flight Manifest and Hardware Tracking System
    FMANTS  Flight Manifest
    FMC     Food Machinery Corporation
    FMCF    First Manned Captive Flight
    FMCS    Federal Mediation and Conciliation Service
    FMDM    Flex Multiplexer/Demultiplexer
    FMEA    Failure Modes and Effects Analysis
    FMEC    Forward Master Events Controller
    FMECA   Failure Mode, Effects, and Criticality Analysis
    FML     Fault Message Line
    FML     Final Materials List
    FMO     Flight Medical Officer
    FMOF    First Manned Orbital Flight
    FMOFEV  First Manned Orbital Flight with EVA
    FMOFPL  First Manned Orbital Flight with Payload
    FMR     Field Modification Request
    FMR     Function Max Rate
    FMS     Food Management System (Subsystem)
    FMSP    Frequency Modulation Signal Processor
    FMSP    FM signal processor
    FMT     Flight Management Team
    FMX     FM Transmitter
    FND     Facility Need Date
    FNL     Final
    FNT     Failure Notification Telex
    FO      Fail Operational
    FO      Fiber Optics
    FO      Functional Objective
    FO/FS   Fail-Operational/Fail-Safe
    FOB     Flight Operations Building
    FOB     Free on Board
    FOC     Focus
    FOC     Full Operational Capability
    FOD     Flight Operations Directorate (JSC)
    FOE     Flight Operations  Engineer
    FOF     First Operational Flight
    FOF     First Orbital Flight
    FOF     Flight Operations Facilities
    FOIA	Freedom of Information Act
    FOIH    Flight Operations Integration Handbook
    FOMR    Flight Operations Management Room
    FOP     Flight Operations Panel
    FOP     Flight Operations Plan
    FOP     Follow on Production
    FOPG    Flight Operations Planning Group
    FOPP    Follow on Parts Production
    FOPS    Flight Operations Planning Schedule
    FOR     Flight Operations Review
    FOR     Force
    FORTRAN Formula Translation
    FOS	Faint Object Spectrograph (on HST)
    FOS     Flight Operations Support
    FOSDIC  Film Optical Sensing Device for Input to Computers
    FOSO    Flight Operations Scheduling Officer
    FOSP    Flight Operations Support Personnel
    FOST    Flight Operations Support Team
    FOT     Flight Operations Team
    FOV     Field of View (Vision)
    FOV     First Orbital Vehicle
    FP      Fine Pointing
    FP      Fixed Point
    FP      Flight Plan
    FP      Freezing Point
    FP      Fuel Pressure
    FP      Function Path
    FPB     Fuel Preburner
    FPBOV   Fuel Preburner and Oxidizer Valve
    FPC     Fluids Pressure Control
    FPC     Forward Power Controller
    FPCA    Forward Power Control Assembly
    FPE     Functional Program Element
    FPEG    Fast Pulse Electron Gun
    FPHB    Flight Procedures Handbook
    FPIF    Fixed Price Incentive Fee
    FPL     Florida Power & Light Company
    FPL     Full Power Level
    FPL     Full Power Load
    FPM     Folding Platform Mechanism
    FPM     Feet per Minute
    FPOV    Fuel Preburner Oxidizer Valve
    FPP     Freon Pump Package
    FPPR    Fixed Price with Price Revision
    FPR     Flight Performance Reserve
    FPS     Feet Per Second
    FPS     Flight Per Second
    FPS	Floating Point System
    FPS	Focal Plane Structure
    FPS     Forward Power Supply
    FPS     Frames Per Second
    FPS2    Feet Per Second Squared
    FPU     Floating Point Unit
    FPV     Flow Proportioning Valve
    FQ      Flight Qualification
    FQI     Flight Qualification Instrumentation
    FQR     Flight Qualification Review
    FQR     Flight Qualification Recorder
    FQT     Formal Qualification Test
    FR      Firing Room
    FR      Flight Rule
    FR      Frame
    FRAGNET Fragmented Network
    FRAM    Flight Release Attach Mechanism
    FRB     Failure Review Board
    FRC     Flight Research Center, California
    FRCI    Fibrous Refractory Composite Insulation
    FRCS    Forward Reaction Control System (Subsystem)
    FRD     Flight Requirements Document
    FRE     Flight Related Element
    FRE     Format Request Element
    FREQ    Frequency
    FREQ CONV Frequency Converter
    FREQ DIV  Frequency Divider
    FRF     Flight Readiness Firing
    FRFT    Flight Readiness Firing Test
    FRJD    Forward Reaction Jet Driver
    FRL     Fuselage Reference Line
    FRL     Frame Reference Line
    FRM     Fleet Resource Management
    FRMT    Format
    FRP     Fuselage Reference Plane
    FRR     Flight Readiness Review
    FRRID   Flight Readiness Review Item Description
    FRRID   Flight Readiness Review Item Disposition
    FRSI    Felt Reusable Surface Insulation
    FRSI    Flexible reusable surface insulation
    FRT     Frequency ResponseTest
    FRT     Flight Readiness Test
    FRT     Flight Readiness Training
    FRZR    Freezer
    FS      Fail-Safe
    FS      Fail to Sync
    FS      Fault Summary
    FS      Federal Specification
    FS      Fire Suppression
    FS      Flight System
    FS      Freon Servicer
    FS      Full Scale
    FS      Functional Schematic
    FS      Fuselage Station
    FSAA    Flight Simulator for Advanced Aircraft
    FSC     Federal Stock Classification
    FSCM    Federal Supply Code for Manufacturers
    FSCP    Fire Sensor  Control  Panel
    FSD     Flight Simulation Division (JSC)
    FSD     Full Scale Development
    FSE     Flight Simulation Engineer
    FSF     First Static Firing
    FSGS    Flare/Shallow Glide Slope
    FSI     Final Systems Installation
    FSIM    Functional Simulator
    FSIWG   Flight System Interface Working Group
    FSK     Frequency Shift Keyed (Keying)
    FSL     Flight Simulation Laboratory
    FSL     Flight Systems Laboratory
    FSLO    First Spacelab Payload
    FSLT    First Sea Level Test
    FSM     Fuel Supply Module
    FSN     Federal Stock Number
    FSO     Functional Supplementary Objective
    FSOH    Flight Support Operations Handbook
    FSOP    Florida Safety Operating Plan
    FSP     Fault Summary Page
    FSR     Final System Release
    FSR     Flight Specific Requirements
    FSRR    Flight System Readiness Review
    FSRR    Flight Software Readiness Review
    FSRS    Flight System Recording System
    FSS     Field  Spectrometer System
    FSS     Fire Suppression System
    FSS     Fixed Service Structure
    FSS     Flight Support Station (for MMU)
    FSS     Flight Support Structure
    FSS     Flight Support System
    FSS     Flight Systems Simulator
    FSSR    Functional Subsystem Software Requirements
    FSSR    Flight Systems Software Requirements
    FSTE    Factory Special Test Equipment
    FSU     Freon Servicing Unit
    FSW     Flight Software
    FT      Feet
    FT      Flight Team
    FT      Flight Test
    FT      Formal Training
    FT      Functional Test
    FT/SEC  Feet per Second
    FT&C    Formal Training and Certification
    FTA     Fatigue Test Article
    FTA     Fault Tree Analysis
    FTA     Flight Test Article
    FTC     Flight Test Conductor
    FTC     Florida Test Center (MDAC)
    FTE     Factory Test Equipment
    FTE     Flight Test Engineer
    FTE     Forced Test End
    FTE     Full Time Equivalent
    FTIS    Flight Test Instrumentation System
    FTO     Flight Test Objective
    FTO     Functional Test Objective
    FTOH    Flight Team Operations Handbook
    FTOH    Flight Test Operations Handbook
    FTP     Flight Test Procedure
    FTP     Full Throttle Position
    FTP     Function Test Progress
    FTP     Functional Test Program
    FTR     Flight Test Requirement
    FTR     Functional Test Requirement
    FTRD    Flight Test Requirements Document
    FTRD    Functional Test Requirements Document
    FTS     Federal Telecommunications System
    FTS     Flight Test Station
    FTS     Flight Test System
    FTS     Functional Test Specifications
    FU      Flight Unit
    FU      Fuel
    FUB     Forward Utility Bridge
    FUD     First Use Date
    FUNC    Function
    FUNCT   Functional
    FUO     Follow-up Output
    FUS     Fuselage
    FUS/LF  Fuselage, Lower Forward
    FUS/UF  Fuselage, Upper Forward
    FUSLG   Fuselage
    FV      Flight Version
    FV      Front View
    FVF     First Vertical Flight
    FVMS    Fluid Volume Measurement System
    FVV     Facility Verification Vehicle
    FW      Flag Word
    FW      Fuel Wasting
    FWB     Fahrenheit Wet Bulb
    FWC	Filament Wound Case
    FWD     Forward
    FWD HT SHLD  Forward Heat Shield
    FWG     Facility Working Group
    FWHM	Full Width at Half Maximum
    FWSI	Fairchild-Weston Systems, Inc.
    FWW     Food, Water, and Waste
    FWWM    Food, Water, and Waste Management
    FWWMS   Food, Water, and Waste Management System (Subsystem)
    FXD     Fixed
    FY      Fiscal Year
    
    G
    
    2GRLV   2nd Generation Return to Launch Vehicle
    G       Giga (Billion)
    G       Gravity
    G       Gravitational Constant
    G       Units of Gravitational Force
    g       gram
    G&A     General and Administrative
    G&C     Guidance and Control
    G&N     Guidance and Navigation
    G&NS    Guidance and Navigation Subsystem
    G-A     Ground-to-Air
    G-G     Ground-to-Ground
    G-II    Gulfstream II (Shuttle Training Aircraft)
    G-GPRF  Gradient General Purpose Rocket Furnace
    G-MEM   General Memory
    G-MEM   GPC-Memory
    G-V     Gravity-Velocity
    G/A     Ground-to-Air
    G/E     Graphite Epoxy
    G/G     Ground-to-Ground
    G/S     Guided steering
    G/T     Antenna Gain-to-Noise Temperature Ratio
    G/T     Gradient-to-Cooling Ratio
    GA      Gage
    GA      General Assembly
    GA      Glide Angle
    GA      Gyro Assembly
    GA&CS   Ground Acquisition and Command Station
    GAC     Ground Attitude Control
    GAC     Grumman Aerospace Corporation
    GACU    Ground Air Conditioning Unit
    GACU    Ground Avionics Cooling Unit
    GAIN    Graphic Aids for Investigating Networks
    GAM     Gamma
    GAO     Government Accountability Office (formerly General Accounting Office until July 2004)
    GAP     GOAL Automatic Procedure
    GAPL    Group Assembly Parts List
    GAS     Get-Away Special
    GASPI   Guidance Attitude Space Position Indicator
    GATP    Ground Acceptance/Article Test Procedure
    GATT    Gate Assisted Turnoff Thyristor
    GBI     Grand Bahama Island
    GBL     Government Bill of Lading
    GBR     Glass Bead Rating
    GBS     Ground Based Software
    GC      Gigacycles (1000 Megacycles)
    GC      Ground Control
    GC      Guidance Control
    GC      Gyrocompassing
    GCA     Ground Controlled Approach
    GCC     Ground Communications Coordinator
    GCC     Ground Control Center
    GCCC    Ground Control Computer Center
    GCCO    Ground Control Checkout
    GCD     Gyro-Compass, Desired Cluster Orientation
    GCDC    Ground Checkout Display and Control
    GCDCS   Ground Checkout Display and Control System
    GCE     Ground Checkout Equipment
    GCF     Ground Communications Facility
    GCHX    Ground Cooling Heat Exchanger
    GCI     Ground Controlled Interception
    GCIL    Ground Command Interface Logic
    GCIL    Ground Control Interface Logic
    GCILC   Ground Command Interface Logic Controller
    GCILU   Ground Control Interface Logic Unit
    GCL     Ground Control Landing
    GCL     Ground Coolant Loop
    GCN     Ground Communications Network (A/G Worldwide Net)
    GCN     Ground Control Network
    GCO     Ground Checkout
    GCOS    General Computer Operational System
    GCOS    Ground Computer Operating System
    GCR	Galactic Cosmic Ray
    GCR     Ground Controlled Radar
    GCS     Ground Communications System
    GCS     Guidance Cutoff Signal
    GCTS    Gas Component Test Stand
    GCTS    Ground Communication(s) Tracking System
    GCV     Gaseous Oxygen Control Valve
    GCU     General Control Unit
    GCU     Generator Control Unit
    GCU     Ground Cooling Unit
    GCU     Gyro Coupling Unit
    GD      Guard
    GDA     Gimbal Drive Actuator/Assembly
    GDBS    Generalized Data Base System
    GDC     General Dynamics Convair
    GDC     Gyro Display Coupler
    GDP     Generalized Documentation Processor
    GDS     GNC Dynamic Simulator
    GDS     Goldstone, California (STDN)
    GDSD    Ground Data Systems Division
    GDSM    Ground Data Systems Manager
    GDSO    Ground Data Systems Officer
    GDSSR   GDSD Staff Support Room
    GDX     Goldstone, CA (STDN Site, 2nd Antenna)
    GE      General Electric
    GECALL  GCOS Program Element Name
    GEDAC   General Electric Detection and Automatic Correction
    GEN     Generate, Generator
    GENOPAUSE Geodetic Satellite in Polar Geosynchronous Orbit
    GEOD    Geodetic
    GEOSEPS General Summary Edit Program
    GEOSEPS Geosynchronous Solar Electric Propulsion Stage
    GERT    Graphical Evaluation and Review Technique
    GES     Goddard Experiment Support System
    GESYOT  GCOS Program Element Name
    GET     Ground Elapsed Time
    GETI    Ground Elapsed Time of Ignition
    GETIL   Ground Elapsed Time of Landing (for TIG of Abort Burn)
    GETS    Ground Equipment Test Sets
    GF      Gage Factor
    GF&P    Gases, Fluids, and Propellants
    GFAE    Government Furnished Aerospace Equipment
    GFAE    Government Furnished Aircraft Equipment
    GFD     Government Furnished Data
    GFE     Government Furnished Equipment
    GFFC    Geophysical Fluid Flow Cell Experiment
    GFGAS   Gradient Furnace for Get Away Special Canister
    GFM     Government Furnished Material
    GFP     Government Furnished Property
    GFRP    Glass Fiber Reinforced Plastics
    GFRP    Graphite Fiber Reinforced Plastics
    GFS     Government Furnished Software
    GFY     Government Fiscal Year
    GG      Gas Generator
    GG      Gravity Gradient
    GH2     Gaseous Hydrogen
    GHA     Greenwich Hour Angle
    GHA     General Housekeeping Area
    GHC     Ground Half Coupling
    GHX     Ground Heat Exchanger
    GHe     Gaseous Helium
    GHz     Gigahertz
    GIA     GPC Interface Adapter
    GIDEP   Government-Industry Data Exchange Program
    GIE     Ground Instrumentation Equipment
    GIM     Generalized Information Management
    GIRD    Ground Integration Requirements Document
    GIS     Geographic Information System
    GITG    Ground Interface Technical Group
    GIWG    Ground Interface Working Group
    GLA     General Luminary Assembly
    GLAADS  Gun Low Altitude Air Defense System
    GLAST	Gamma-ray Large Area Space Telescope 
    GLC     Generator Line Contractor
    GLD     Glide Slope
    GLL     Galileo
    GLOW    Gross Lift-Off Weight
    GLOW    Ground Lift-Off Weight
    GLP     Goal Language Processor
    GLRSHLD Glare Shield
    GLS     Ground Launch Sequence (Sequencer)
    GLY     Glycol
    GLY     Water-Glycol Mixture
    GM      Gaseous Mixture
    GM      Geometric Mean
    GMAL    General Electric Macro Assembly Language
    GMBL    Gimbal
    GMCL    Ground Measurements Command List
    GMIL    Spaceflight Tracking and Data Network (STDN)
    GML     General Measurement Loop
    GMML    Ground Master Measurements List
    GMN     Gorman (TACAN Station)
    GMT     Greenwich Mean Time
    GN      Gain
    GN	Ground Network
    GN2     Gaseous Nitrogen
    GN&C    Guidance, Navigation and Control
    GNC     Guidance and Navigation Computer
    GNCFTS  GN&C Flight Test Station
    GNCIS   GN&C Integration Simulator
    GNCS    Guidance and Navigation Control System
    GNCTS   GN&C Test Station
    GND     Ground
    GND C/O Ground Checkout
    GNP     Gross National Product
    GO      General Order
    GO2     Gaseous Oxygen
    GOAL    Ground Operations Aerospace Language
    GOC     Ground Operations Coordinator
    GOCA    Ground Operations Control Area
    GOE     Ground Operating Equipment
    GOES    Geostationary Environmental Satellite System
    GOES    Geostationary Operational Environment Satellite
    GOES    Geosynchronous Operational Environmental Satellite
    GOM     KSC Ground Operations Manager at DFRC or WSMR
    GOMMS   Ground Operations and Material Management System
    GOMS    Ground Operations Management System
    GOP     Ground Operations Panel
    GOPG    Ground Operations Planning Group
    GOR     Ground Operations Review
    GORP    Ground Operations Requirements Plan
    GORP    Ground Operations Review Panel
    GORS    Ground Observer RF System
    GOSS    Ground Operations Support System
    GOWG    Ground Operations Working Group
    GOX     Gaseous Oxygen (GO2)
    GP      General Purpose
    GP      General Publication (RSC)
    GP      Group
    GP-B	Gravity Probe B
    GPA     General Purpose Amplifier
    GPAS    General PurPose Airborne Simulator
    GPBIM   General Purpose Buffer Interface Module
    GPC     Gel Permeation Chromatograph
    GPC     General Purpose Computer
    GPCB    GOAL Program Control Block
    GPD     Gimbal Position Display
    GPES    Goal Performance Evaluation System
    GPH     Gallons per Hour
    GPI     Gimbal Position Indicator
    GPI     Ground Position Indicator
    GPL     General Purpose Laboratory
    GPL     Goal Processing Language
    GPM     Gallons per Minute
    GPME    General Purpose Mission Equipment
    GPRN    GOAL Test Procedure Release Notice
    GPS     Gallons per Second
    GPS     General Processing Subsystem
    GPS     Global Positioning Satellite
    GPS     Global Positioning System
    GPS     Ground Power Supply
    GPS     Ground Processing Simulation
    GPSS    General Purpose System Simulator
    GPTE    General Purpose Test Equipment
    GPU     Ground Power Unit
    GPUR    GOAL Test Procedure Update Request
    GR      Ground Rule
    GRC     Glenn Research Center
    GRE     Gamma Ray Explorer
    GRID    Graphic Retrieval and Information Display
    GRN     Green
    GRO     Gamma Ray Observatory
    GRTLS   Glide Return to Launch Site
    GRTLS   Glide Return to Landing Site
    GS      Gas Servicer
    GS      Glide Slope
    GS      Ground Speed
    GS      Ground Station
    GS      Ground System
    GSA     General Services Administration
    GSAT    General Satellite (STS)
    GSCU    Ground Service Cooling Unit
    GSDL    Ground Software Development Laboratory
    GSE     Ground Servicing Equipment
    GSE     Ground Support Equipment
    GSEL    Ground Support Equipment List
    GSFC    Goddard Space Flight Center (Greenbelt, MD)
    GSI     Government Source Inspection
    GSI     Glide Slope Indicator
    GSIU    Ground Standard Interface Unit
    GSO     Ground Support Office
    GSO     Ground Support Operations
    GSO     Ground Systems Operations
    GSOC	Guide Star Occultation Utility
    GSRP    Ground Safety Review Panel
    GSS     Ground Support Software
    GSS     Ground Support System
    GSSA    Ground Support Systems Activation
    GSSC    Ground Support Simulation Computer
    GSSC    Ground Support Systems Contractor
    GSSI    Ground Support System Integration
    GST     Ground System Test
    GSTAR   General Satellite (ELV)
    GSTDN   Ground Spacecraft Tracking and Data Network
    GSTDN   Ground Space Flight Tracking and Data Network
    GSTF    Ground Systems Test Flow
    GSU     Gas Servicer Unit
    GSVP    Ground Support Verification Plan
    GT      Greater Than
    GT      Ground Team
    GT      Ground Test
    GT      Gyro Torque
    GT&A    Ground Test and Acceptance
    GTA     Gas Tungsten Arc
    GTA     Ground Test Access
    GTA     Ground Test Article
    GTA     Ground Torquing Assembly
    GTC     Glycol Trim Console
    GTC     Ground Test Conductor
    GTCU    Ground Thermal Conditioning Unit
    GTI     Grand Turk Island
    GTI     Ground Test Instrumentation
    GTM     Ground Team Manager
    GTM     Ground Test Motor
    GTS     General Test Support
    GTS     GN&C Test Station
    GTS     GNS Test Station
    GTU     Glycol Trim Unit
    GUCP    Ground Umbilical Carrier Plate
    GUI     Graphical User Interface
    GUID    Guidance
    GUIDO   Guidance Officer
    GUL     GSE Utilization List
    GUSB    Guided Unified S-Band
    GVA     GOX Vent Arm
    GVO     Gaviota (TACAN Station)
    GVT     Ground Vibration Test
    GVTA    Ground Vibration Test Article
    GW      Gross Weight
    GWA     General Work Area
    GWM     Guam (STDN)
    GWT     Ground Winds Tower
    GYM     Guaymas, Mexico (Remote Site)
    GYRO    Gyroscope
    GYROA   Gyro A
    GYROCOMP  Gyrocompassing
    
    H
    
    H       Altitude
    H       Hazardous (Task Classification)
    H       Head
    H       Henry (SI Unit)
    H       High
    H       Horizontal
    H       Hot
    H       Momentum
    h       Hours
    H       Altitude Rate
    (H)     Hazardous (Task Classification)
    H2      Hawaii
    H2      Hydrogen
    H2O     Water
    H-CITE  Horizontal-Cargo Integration Test Equipment
    H/E     Heat Exchanger
    H/L     Hardline
    H/O     Handover
    H/S     Heat Shield
    H/S IR  Hardware/Software Integration Review
    H/T     Heat Treat
    H/W     Hardware
    HA      Apogee Altitude
    HA      Hazard Analysis
    HA      High Altitude
    HAA     High Altitude Abort
    HAB     Habitation
    HABT    Habitability Technology
    HAC     Heading Alignment Center
    HAC     Heading Alignment Circle
    HAC     Heading Alignment Cone
    HAC     Heading Alignment Cylinder
    HACBSS  Homestead and Community Broadcasting Satellite Service
    HAD     Heat Actuated Device
    HAFB    Holloman Air Force Base
    HAINS   High-Accuracy Inertial Navigation System
    HAK     Horizontal Access Kit
    HAL     High Order Articulated Language
    HAL     High Order Assembly Language
    HAL     High Temperature Acoustic Levitator
    HAL     Houston Aerospace Language
    HAL/S   High Order Assembly Language for Shuttle Flight Computer
    HAL/S   High Order Assembly Language/Shuttle
    HAL/S   High Order Programming Language for Spacelab Usage
    HALEX   Halogen Lamp Experiment
    HALOE   Halogen Occultation Experiment
    HAM     Height Adjustment Maneuver
    HAO     High Altitude Observatory
    HAP     Hardware Allocation Panel
    HAPI    High Altitude Plasma Instrument
    HARP    Hyperbolic Analyzer Retarding Potential
    HAS     Holddown Alignment Support
    HAS     Hydraulic Actuation System
    HAS     Hydrogen Actuation System
    HAST    High Altitude Supersonic Target
    HAW     Hawaii (STDN)
    HB      Handbook
    HB      High Bay
    HBR     High Bit Rate
    HBT     Heflex Bioengineering Test
    HBW     Hot Bridge Wire
    HC      Hand Controller
    HC      Head Count
    HC      Hybrid Computer
    HCED    Hand Controller Engage Driver
    HCF     High Cycle Fatigue
    HCF     HIM Configuration File
    HCL     Horizontal Centerline
    HCM     Hard Copy Module
    HCMM    Heat Capacity Mapping Mission
    HCR     High Cross Range
    HCSI    Hughes Communications Services, Inc.
    HCSL    Hybrid Computation and Simulation Laboratory
    HCU     Hydraulic Charging Unit
    HCV     Hydrogen Check Valve
    HD      Hoiddown
    HD      Horizontal Drain
    HD      Hydrogen Drain
    HD      Highly Desirable
    HD      Heavy Duty
    HDA     Housekeeping Data Acquisition
    HDC     HYbrid Device Controller
    HDC     Hasselblad Data Camera
    HDDR    High-Density Digital Recorder
    HDG     Heading
    HDP     Holddown Post
    HDQ     Headquarters
    HDR     High Data Rate
    HDRA    High Data Rate Assembly
    HDRM    High Data Rate Multiplexer
    HDRR    High Data Rate Recorder
    HDRR    High-data-rate recorder
    HDRSS   High Data Rate Storage System
    HDS     Hardware Description Sheet
    HDST    Headset
    HDW     Hardware
    HDWE    Hardware
    HE      Heat Exchange (Exchanger)
    HE      High Energy Astrophysics
    He      Helium
    HEAO    High Energy Astronomy Observatory
    HEAP    High Energy Aim Point
    HECV    Helium Check Valve
    HEDS    Human Exploration and Development of Space
    HEG     Helium Gage
    HEGV    Helium Gage Valve
    HEM     Hitchhike Experiment Module
    HEMI    Hemispherical (S-Band Antenna)
    HEMV    Helium Manual Valve
    HEO     High Energy Orbit
    HEPA    High Efficiency Particle Accumulator
    HEPA    High Efficiency Particle Air (Filter)
    HER     HIM Equipment Rack
    HERSCP  Hazardous Exposure Reduction and Safety Criteria Plan
    HESS    High Energy Squib Simulator
    HETM    Hybrid Engineering Test Model
    HEX     Heat Exchanger
    HEX     Hexadecimal
    HEX     Hexagon
    HF      Hard Failure
    HF      High Frequency
    HF      Horizontal Flight
    HF      Hot Firing
    HF      Hydrogen Fill
    HF      Hyperfiltration
    HFA     High Frequency Accelerometer
    HFC     Heat Flow and Convection
    HFC     Hydraulic Flight Control
    HFCT    Hydraulic Flight Control Test
    HFCV    Helium Flow Control Valve
    HFDS    Hydrogen Fluid Distribution System
    HFE     High Frequency Executive
    HFM     Hollow Fiber Membrane
    HFMU    High Fidelity Mockup
    HFO     High Frequency oscillator
    HFS     Horizontal Flight Simulator
    HFT     Horizontal Flight Test
    HFTF    Horizontal Flight Test Facility
    HFTS    Horizontal Flight Test Simulator
    HFX     High Frequency Transceiver
    HG      High Gain
    HG      Hitchhiker Goddard Mission
    Hg      Mercury
    HGA     High Gain Antenna
    HGAS    High Gain Antenna System
    HGDS    Hazardous Gas Detection System
    HGLDS	Hazardous Gas Leak Detection Subsystem
    HGM     Hot-Gas Manifold
    HGR     Hangar
    HGR&SPTFAC  Hangar and Support Facility
    HGS     Hydrogen Gas Saver
    HGV     Hydrogen Gas Valve
    HGVT    Horizontal Ground Vibration Test
    HHC     Hammer Head Crane
    HHMU    Hand Held Maneuvering Unit
    HI      High
    HI      Honeywell, Inc.
    HIC     Hickam Air Force Base, Hawaii (Deorb OPT site)
    HID     Hardware Interface Device
    HID     HIM Interface Distributor
    HIM     Hardware Interface Module
    HIP     Hardware Interface Program
    HIPC    High Chamber Pressure
    HIPO    Hierarchical Input/Process Output
    HIPO    Hierarchy Plus Input/Process/Output
    HISAM   Hardware Initiated Standalone Memory
    HIST    History
    HITS    High Rate Multiplexer Input/Output Test System
    HIU     Headset Interface Unit
    HIV     Helium Isolation Valve
    HK      Housekeeping
    HL      Hardline
    HL      Heel Line
    HL      High Level
    HL      Hinge Line
    HL      Hydrogen Line
    HLAL    High Level Assembler Language
    HLD     Hold
    HLDS    Hydrogen Leak Detection System
    HLMT    Helmet
    HLTL    High Level Test Language
    HM      Hinge Mount
    HMA     Hypergot Maintenance Area
    HMC     Hybrid Microcircuit
    HMC     Hypergolic Maintenance and Checkout
    HMCC    Hypergolic Maintenance and Checkout Cell
    HMCF    Hypergolic Maintenance and Checkout Facility
    HMD     Helmet-Mounted Display
    HMF     Horizontal Mating Facility
    HMF     Hypergol Maintenance Facility
    HMP     Hydrozene Monopropeflant (RCS Propellant)
    HMS     History Memory System
    HMU     Hardware Mockup
    HMV     Hydrogen Manual Valve
    HNDLER  Handler
    HNGR    Hangar
    HO      Hydrogen-Oxygen
    HOL     High Order Language
    HOLC    High Order Language Computer
    HORIZ   Horizon, Horizontal
    HOS     High Order Software
    HOSC    Huntsville Operations Support Center
    HP      Handling Procedure
    HP      Hewlett Packard
    HP      High Pressure
    HP      Hydrogen Purge
    HP      Perigee Altitude
    HPF     Horizontal Processing Facility (O&C)
    HPFD    High Pressure Fuel Duct
    HPFTP   High Pressure Fuel Turbopump
    HPG     High Pressure Gas
    HPGS    High Pressure Gas System
    HPI     High Performance Insulation
    HPOP    High Pressure Oxidizer Pump
    HPOT    High Pressure Oxidizer Turbopump
    HPOTP   High Pressure Oxidizer Turbopump
    HPPF    Horizontal Payloads Processing Facility
    HPR     Hydrogen Pressure Regulator
    HPRV    Hydrogen Pressure Relief Valve
    HPS     Hydraulic Power System
    HPT     High Pressure Test
    HPU     Hydraulic Power Unit
    HPV     High Pressure Valve
    HQ      Headquarters
    HQR     Handling Qualities Rating (Cooper-Harper)
    HR      Historical Record
    HR      Hydrogen Relief
    hr      Hour
    HRAA    High Rate Acquisition Assembly
    HRAP    High Resolution Accelerometer Package
    HRC     Hasselblad Reflex Camera
    HRD     Hatch Restraint Device
    HRD     High Rate Dosimeter
    HRDA    High Rate Data Assembly
    HRDM    High Rate Demultiplexer
    HRDR    High Rate Digital Recorder
    HRDS    High Rate Data Station
    HRFM    High Rate Frame Multiplexer
    HRIR    High Resolution Infrared Radiometer
    HRL     Horizontal Reference Line
    HRM     High Rate Multiplexer
    HRM     High Ratio Multiplier
    HRPS    Hazard Reduction Precedence Sequence
    HRS     Hours
    HRSI    High Temperature Reusable Surface Insulation
    HROS    High Resolution Objective Spectrometer
    HRT     High Resolution Tracker
    HS      Heat Shield
    HS      High Speed
    HS      Horizon Sensor
    HS-C    Hamilton Standard CO2 Absorbent Material
    HSC     Hardware/Software Coordination
    HSCU    Hydraulic Supply and Checkout Unit
    HSD     Horizontal Situation Display
    HSD     High Speed Data
    HSD     Hamilton Standard Division
    HSDL    High Speed Data Line
    HSF     Hypergot Servicing Facility
    HSG     High Sustained Gs Acceleration
    HSI     Horizontal Situation Indicator
    HSK     Horizontal Sling Kit
    HSL     Hardware Simulation Laboratory
    HSNG    Housing
    HSP     Health Stabilization Program
    HSP     High Speed Printer
    HSR     Hardware Status Register
    HSS     High Speed Reader
    HSS     High Stress Strain
    HSS     Hydraulic Subsystem Simulator
    HST     Hubble Space Telescope
    HSTP    Hard Stop
    HSU     Helium Service Unit
    HT      Heat Transfer
    HT      Height
    HT      High Technology
    HTC     Hybrid Technology Computer
    HTEXCH  Heat Exchanger
    HTG     Heating
    HTLL    High Test Level Language
    HTM     High Temperature
    HTPB    Hydroxyl Terminated Polybutadiene (Propellant)
    HTR     Heater
    HTR     Hydroxyl Terminated Polybutyiene
    HTS     Heat Transfer System
    HTS     Heat Transport Section
    HUD     Head Up Display
    HUDE    Head Up Display Electronics
    HUL     Hardware Utilization List
    HUM     Humidity
    HUT     Hard Upper Torso
    HV      High Velocity
    HV      High Voltage
    HV      Hydrogen Vent
    HVAC    Heating, Ventilating, and Air Conditioning
    HVDS    Hypergolic Vapor Detection System
    HVPS    High Voltage Power Supply
    HVR     Hover
    HVSF    Honeywell Verification Simulation Facility
    HVSL    Holidays, Vacation, and Sick Leave
    HW      Hardware
    HW      Headwind
    HW      Hotwire
    HW/SW   Hardware/Software
    HWWS    Hyperfiltration Wash Water Recovery System
    HX      Heat Exchanger
    HXIS    Hard X-ray Imaging Spectrometer
    HYD     Hydraulic Subsystem
    HYD     Hydraulics
    HYGL    Hypergolic
    HYPACE  Hybrid Programmable Attitude Control Electronics
    Hz      Hertz (Cycles Per Second)
    HZE     Highly Charged and Energetic Particles
    
    I
    
    I       Inertias
    I       Inner
    I       Iodine
    I       Irradiated
    I LOAD  Initialization Load
    I&C     Installation and Checkout
    I&C/O   Installation and Checkout
    I&PS    Institutional and Program Support
    I&O     Inlet and Outlet
    I&R     Interchangeability and Replaceability
    I&R     Interchangeability and Replacement
    I&RS    Instrument and Range Safety
    I&S     Interchangeability and Substitutability
    I&T     Integration and Test
    I-GPRF  Isothermal General Purpose Rocket Furnace
    I-LOS   Initial Data Load
    I/A     Interface Adapter
    I/C     Intercom
    I/E     Input Electronics
    I/F     Interface
    I/FU    Interface Unit
    I/O     Input/Output
    I/OB    Input/Output Bus
    I/OC    Input/Output Controller
    I/OMI   Integration/Operations and Maintenance Instruction
    I/OP    Input/Outboard Profile
    I/OT    Input/Output Test
    I/OU    Input/Output Unit
    I/P     In Progress
    I/T     Intertank
    I/V     Inlet Valve
    IA      Implementation Agency
    IA      Input Axis
    IA      Inverter Assembly
    IA      Issuing Agency
    IA/V    Internal Audio and Video
    IAA     International Aerospace Abstracts
    IAB     IUS Assembly Building
    IAC     Integrated Analysis Capability
    IAC     Interface Adapter Unit
    IACS    Inertial Attitude Control System
    IAD     Interface Agreement Document
    IAD     Interface Analysis Document
    IAL     Immediate Action Letter
    IAL     International Algebraic Language
    IandC   Instrument and Communication
    IandC   Instrumentation and Communication
    IAM     International Association of Machinists
    IARS    Independent Air Revitalization System
    IAS     Impact Assessment Sheet
    IAS     Indicated Airspeed
    IAS     Integrated Avionics System
    IASS    Inverter/ATCS Support Structure
    IAT     Integrated Avionics Test
    IAU     International Astronomical Union
    IAV     Inventory Adjustment Voucher
    IB      Inboard
    IB      Inert Building
    IB      Instruction Book
    IBF     Internally Blown Flap
    IBM     International Business Machines
    IBSE    Initial Blood Storage Experiment
    IBSS    Infrared Background Signature Survey
    IC      Incremental Cost
    IC      Information Center
    IC      Initial Condition
    IC      Integrated Circuit
    IC      Intercom (Orbiter to Ground via Hardline)
    IC      Intercommunications
    IC      Intercomputer
    IC      Intercomputer Communication
    IC      Interim Change
    IC      Internal Combustion
    IC      Ion Chamber
    IC/ES   Intercommunication/Emergency Station
    ICA     Item Change Analysis
    ICAO    International Civil Aviation Organization
    ICAR    Investigation and Corrective Action Report
    ICAT    Integrated Change Assessment Team
    ICB     Interim Change Bulletin
    ICB     Interrupt Control Block
    ICBC    IMAX Cargo Bay Camera
    ICC     Intercomputer Channel
    ICC     Intercomputer Communication
    ICC     Interface Control Chart
    ICC     Interstate Commerce Commission
    ICCB    Integrated Change Control Board
    ICCP    Interface Coordination and Control Procedure
    ICD     Interface Control Document
    ICD     Interface Control Drawing
    ICDR    Incremental Critical Design Review
    ICDU    Inertial Coupling Data Unit
    ICE     Input Control Element
    ICE     Instrument Checkout Equipment
    ICE     Instrument/Communication Equipment
    ICF     Interface Control Function
    ICG     In-Flight Coverall Garment
    ICH     Interchanger
    ICIO    Interim Cargo Integration Operations
    ICMO    Integrated Configuration Management Office
    ICMS    Indirect Cost Management System
    ICMS    Integrated Configuration Management System
    ICMS    Intercom Master Station
    ICMT    Intercontract Material Transfer
    ICO     Integrated Checkout
    ICOM    Intercommunications
    ICOS    Improved Crew Optical Sight
    ICOU    Inertial Coupling Data Unit
    ICP     ICS Control Program
    ICP     Inventory Control Point
    ICR     Instruction Change Request
    ICR     Interface Compatibility Record
    ICS     Instrumentation Control System
    ICS     Integrated Checkout Station
    ICS     Intercommunication System
    ICS     Interface Control Specification
    ICS     Interpretive Computer Simulator
    ICT     Influence Coefficient Tests
    ICT     Interface Control Tooling
    ICTC    Inertial Components Temperature Controller
    ICU     Interface Control Unit
    ICW     Interrupted Continuous Wave
    ICWG    Interface Control Working Group
    ID      Identification
    ID      Identification Data
    ID      Inside Diameter (id preferred)
    ID      Interface Document
    ID&CA   Inverter Distribution and Control Assembly
    IDA     Interface Display Assembly
    IDAC    Integrated Digital-Analog Converter
    IDAS    Integrated Data Acquisition System
    IDB     lnsuit Drink Bag
    IDC     IMBLMS Digital Computer
    IDC     Integrated Displays and Controls
    IDC     Interface Document Control
    IDCA    Inverter Distribution and Control Assembly
    IDD     Interface Definition Document(s)
    IDE     Initial Design Evaluation
    IDG     Integrated Drive Generator
    IDI     InDyne, Inc.
    IDI     Instrumentation Data Items
    IDLH    Immediately Dangerous to Life and Health 
    IDMM    Intermediate and Depot Maintenance Manual
    IDO     Interdivisional Operations
    IDP     Integrated Data Processor
    IDPS    Interface Digital Processor
    IDR     Intermediate Design Review
    IDR     Interim Discrepancy Report
    IDR     Initial Design Review
    IDRD    Internal Data Requirement Description
    IDRD    Information Definition Requirements Document
    IDS     Interface Data Sheet
    IDS     Item Description Sheet
    IDSD    Institutional Data System Division (JSC)
    IDSO    Interdivisional Sales Order
    IDT     I-Load Data Tape
    IDTA    Interdivisional Technical Agreement
    IDU     Interface Demonstration Unit
    IDWA    Interdivisional Work Authorization
    IE      Industrial Engineering
    IEA     Integrated Electronic Assembly
    IECM    Induced Environment Contamination Monitor
    IECO    Inboard Engine Cutoff
    IECS    Igloo Environment Control Subsystem
    IED     Interacting Equipment Documents
    IEEE	Institute of Electrical and Electronics Engineers
    IEF     Isoelectric Focusing
    IEP     Instantaneous Effective Photo Cathodes
    IF      Inertial Fusion
    IF      Integration Facility
    IF      Intermediate Frequency
    IFA     In-Flight Analyses
    IFA     Interface Functional Analysis
    IFASC   Integrated Functions Assessment Steering Committ
    IFB     Invitation for Bid
    IFM     In-Flight Maintenance
    IFO     Information Systems Office
    IFOT    In-Flight Operations and Training
    IFR     Instrument Flight Rules
    IFRU    In-Flight Replacement Unit
    IFT     In-Flight Test
    IFTM    In-Flight Test Maintenance
    IFTS    In-Flight Test System
    IFU     Interface Unit
    IG      Igloo
    IGA     Inner Gimbal Angle
    IGAX    Inner Gimbal Axis
    IGDS    Iodine Generating and Dispensing System
    IGM     Interactive Guidance Mode
    IGN     Ignition, Ignite
    IGOR    Intercept Ground Optical Recorder
    IGS     Inertial Guidance System
    IGSE    In-Space Ground Support Equipment
    IGV     Inlet Guide Valve/Vanes
    IH/SR   Integration Hardware and software Review
    IHP     Indicated Horsepower
    IHTV    Interim Hypersonics Test Vehicle
    IHX     Interloop Heat Exchanger
    IIG     Interrange Instrumentation Group
    IIS     Inspection Item Sheet
    IITCS   Igloo Internal Thermal Control Section
    ILA     Instrument Landing Approach
    ILAS    Instrument Landing Approach System
    ILC     Initial Launch Capability
    ILC     Intermediate Loads Cycle
    ILC     International Latex Corporation
    ILCCS   Integrated Launch Control and Checkout System
    ILLUM   Illuminate
    ILS     Instrument Landing System
    ILP     Integrated Logistics Panel
    ILS     Integrated Logistics Support
    ILS     Integrated Logistics System
    ILS/LAR Integrated Logistics System and Logistics Assess Review
    ILSP    Integrated Logistics Support Plan
    ILSSE   Integrated Life Science Shuttle Experiments
    IM      Information Memory
    IM      Inner Maker
    IM      Instrument Module
    IM      Interface Module
    IM      Interim Mission
    IM      Intermediate Moisture
    IMAP    Intergrated Mission Analysis Planning
    IMAX    Shuttle Cabin Camera (Manufactured by IMAX, Inc.)
    IMBLMS  Integrated Medical Behavioral Laboratory Measurement System
    IMC     Image Motion Compensation
    IMCC    Integrated Mission Control Center
    IMCP    Integrated Monitor and Control Panel
    IMD     Intermediate
    IMDB    Integrated Maintenance Data Base
    IME     International Magnetospheric Explorer
    IMF     Inventory Master File
    IMIC    Integrated Management Information Computer
    IML     Inside Mold Line
    IML     International Microgravity Laboratory
    IMP     Initial Memory Protection
    IMP     Interplanetary Monitoring Platform
    IMPD    Impedance
    IMPL    Implement
    IMPLS   Impulse
    IMS     Information Management System
    IMS     Institutional Management Support
    IMS     Inventory Management System
    IMSL    Intermediate Seal
    IMU     Inertial Measurement Unit
    IMU     Internal Measurement Unit
    IN      Information Systems Directorate (KSC)
    IN      Inlet
    in      Inch
    INBD    Inboard
    INBIT   Input Bit
    INC     Incomplete
    INC     Increase
    INC     Installation Notice Card
    INC     Installation Notice Certificate
    INCL    Inclination
    INCL    Include
    INCLN   Incline
    INCO    Inconel (nickel, chromium, and iron)
    INCO    Instrumentation and Communication Officer
    INCR    Increase
    INCR    Increment
    INCS    Integrated Network Control System
    IND     Indicate, Indicator
    IND     Industrial
    INDAT   Incoming Data
    INF     Infinite
    INFT	Informal Training
    INH	Inhibit
    INIT	Initial
    INIT	Initiate
    INJ	Inject
    INL	Inlet
    INMARSAT International Maritime Satellite
    INOP	Inoperative
    INP	Input
    INR	Inertial Reference
    INRTL	Inertial
    INRTL VEL Inertial Velocity
    INS     Inertial Navigation System
    INS	Insertion Burn, OMS1
    INSAT	Indian National Satellite
    INSL	Insulate
    INSP	Inspect, Inspection
    INSPEX	Indonesia Space Experiment
    INSRP	Interagency Network Safety Review Panel
    INST	Instrument
    INST SYS Instrumentation System
    INST/COMM Instrumentation and Communication
    INSTL	Install, Installation
    INSTL&C/O Installation and Checkout
    INSTR   Instruct
    INSTR   Instrument, Instrumentation
    INSTRUM Instrumentation Subsystem
    INT     Integrated Test
    INT     Intensity
    INT     Internal
    INTASAT Instituto Nacional De Technica Aeroespacial Satellite
    INTC/O  Integrated Checkout
    INTCHG  Interchange
    INTCHGR Interchanger
    INTCP   Intercept
    INTEGR  Integrate, Integration
    INTELSAT International Telecommunications Satellite Organization
    INTEROG Interrogate
    INTF    Interface
    INTG    Integration
    INTLK   Interlock
    INTR    Interior
    INTRG   Interrogate
    INTRLVR Interleaver
    INTRPT  Interrupt
    INTV    Interim Hypersonics Test Article
    INTVL   Interval
    INTVLM  Intervalometer
    INV     Inverter
    INV MGT Inventory Management
    IOA     Input/Output Adapter
    IOA     Input/Output or Assembly
    IOB     Input/Output Box
    IOB     Input/Output Buffer
    IOBPS   Input/Output Box and Peripheral Simulator
    IOC     Indirect Operating Costs
    IOC     Initial Operating Capability
    IOC     Initial Operational Capability
    IOC     Input/Output Controller
    IOCM    Interim Operational Contamination Monitor
    IOCU    Input/Output Control Unit
    IOE     Input/Output Error Log Table
    IOF     Initial Operational Flight
    IOM     Input/Output Module
    IONS    Studies of the Ionization States of Solar and Galactic Cosmic Ray
    IONS    Heavy Nucleii
    IOP     In-Orbit Plane
    IOP     Input/Output Port
    IOP     Input/Output Processor
    IOP     Integrated Operation Plan
    IOP     Internal Operating Plan
    IOPL    Integrated Open Problem List
    IOQE    Input/Output Queue Element
    IOS     Indian Ocean Ship (STDN)
    IOS     Indian Ocean STDN Site
    IOS     Input/Output Supervision
    IOS     Instructor Operator Station
    IOSC    Integrated Operations Support Center
    IOSS    Integrated Orbital Service System
    IOU     Input/Output Unit
    IP      Identification of Position
    IP      Igloo Pallet
    IP      Impact Point
    IP      Inertial Processing
    IP      Instructor Pilot
    IP      Instrumentation Payload
    IP      Instrumentation PCM Data Bus
    IP      Intermediate Pallet
    IP      Intermediate Pressure
    IP      International Partner
    IPA     Intergovernmental Personnel Action
    IPA     Isopropyl Alcohol
    IPACS   Integrated Power and Attitude Control System
    IPAD    Integrated Program for Aerospace Vehicle Design
    IPB     Illuminated Push Button
    IPB     Illustrated Parts Breakdown
    IPC     Intermittent Positive Control
    IPCL    Instrumentation Program and Component List
    IPD     Information Processing Division
    IPDR    Incremental Preliminary Design Review
    IPE     Industrial Plant Equipment
    IPF     IUS Processing Facility
    IPL     Indentured Parts List
    IPL     Initial Program Load
    IPR     Interim Problem Report
    IPS     Inches per Second
    IPS     Instrument Pointing System (Subsystem)
    IPS     Instrumentation Power Subsystem
    IPS     Interface Problem Sheets
    IPS     International Pipe Standard
    IPS     Inverter Power Supply
    IPSL    Interface Problem Status Log
    IPT     In-Plant Transporter
    IPT     Integrated Product Team
    IPT     International Pipe Thread
    IPTCS   Igloo Passive Thermal Control Section
    IR      Inclination of the Ascending Return
    IR      Infrared
    IR      Inside Radius
    IR      International Rendezvous
    IR SPECT  Infrared Spectrometer
    IRAD    Internal/Independent Research and Development
    IRAN    Inspection and Repairs as Necessary
    IRANSAT Iranian Government Communications Satellite (replaces IRAN)
    IRAR    Internal Variable
    IRD     Information Requirements Document
    IRD     Initiating Reference Document
    IRG     Inertial Rate Gyro
    IRG     Inner Roll Gimbal
    IRIG    Inertial Rate Integrating Gyro
    IRIG-B  Interrange Instrumentation Group B
    IRIS    Italian Research Interim Stage
    IRL     Initiating Reference Letter
    IRL     Interface Requirement List
    IRME    Initiator Resistance Measuring Equipment
    IRN     Interface Revision Notice
    IRR     Inspection Rejection Report
    IRR     Integral Rocket Ramjet
    IRTCM   Integrated Real-Time Contamination Monitor
    IRU     Inertial Reference Unit
    IRV     Isotope Reentry Vehicle
    IS      Installation Support
    IS      Interconnecting Station
    ISA     Interim Stowage Assembly
    ISC     Initial Software Configuration Map
    ISD     Instructional Systems Development (USAF)
    ISE     Integrated Synthesis Environment
    ISEE    International Sun-Earth Explorer
    ISF     Industrial Space Facility
    ISI     Initial Systems Installation
    ISI     Instrumentation Support Instruction
    ISIL    Interim Support Items List
    ISIS    International Satellite for Ionospheric Studies
    ISL     Inertial Systems Laboratory
    ISL/LAR Integrated Logistics System and Logistics Assessment Review
    ISLM    Integration Shop/Lab Manager
    ISN	Inter-Set Network
    ISO     Imaging Spectrometric Observatory
    ISO     Information Systems Office
    ISO     International Organization for Standardization (not an acronym, a short form of the name chosen by the organization)
    ISOC    Institutional Safety Office Contact
    ISOL    Isolate, Isolation
    ISP     Initial Specific Impulse
    ISP     Instrumentation Support Plan
    ISP     Integrated Support Plan
    ISPG    Institutional Support Planning Group
    ISPM    International Solar Polar Mission
    ISPR    International Standard Payload Rack
    ISR     Initial System Release
    ISS     Inertial Subsystem
    ISS     Inhibit/Override Summary Snapshot Display
    ISS     Installation Support Services
    ISS     Instruction Summary Sheet
    ISS     Integrated Support Stand
    ISS     Integrated System Schematic
    ISS     International Space Station
    ISS     IRIS Spinning Stage
    ISSL    Initial Spares Support List
    ISTA    Intertank Structural Test Assembly
    ISTB    Integrated Subsystem Test Bed
    ISTF    Integrated System Test Flow
    ISU     Instrument Switching Unit
    ISU     International Systems of Units
    IT      Identification Transponder
    IT      Installation Test
    ITA     Integrated Test Area
    ITA     Integrated Test Article
    ITA     International Television Academy
    ITAP    Integrated Technical Assessment Panel
    ITC     Igloo Thermal Control
    ITCB    International Training Control Board
    ITCS    Internal Thermal Control System
    ITE     Instrumentation Test Equipment
    ITE     Integration Test Equipment
    ITE     Intersite Transportation Equipment
    ITI     Inspection and Test Instruction
    ITL     Integrate, Transfer, and Launch
    ITMG    Integrated Thermal/Micrometeoroid Garment
    ITO     Integration and Test Order
    ITRDS   Integrated Test Requirements Documents
    ITS     Instrumentation Telemetry Station
    ITS     Interim Teleprinter System
    IU      Instrument Unit
    IU      Interface Unit
    IUA     Inertial Unit Assembly
    IUA     Interface Unit Adapter
    IUCS    Instrumentation Unit Update Command System
    IUCS    Instrumentation Update Command System
    IUE     Interface Unit Error Count Table
    IUE     International Ultravioet Explorer
    IUS     Inertial Upper Stage (was Interim Upper Stage)
    IUS     Interim/Intermediate Upper Stage
    IUS     Interim Use Sheet
    IUS     Interior Upper Stage
    IV      Initial Velocity
    IV      Integrated Vehicle
    IV      Interface Volume
    IV      Intravehicular
    IVA     Intravehicular Activity
    IVAK    Igloo Vertical Access Kit
    IVAR    Internal Variable
    IVBC    Integrated Vehicle Baseline Configuration
    IVC     Intervehicular Communications
    IVE     Interface Verification Equipment
    IVHM    Integrated Vehicle Health Monitoring
    IVL     lntervatometer
    IVSI    Instantaneous Vertical Speed Indicator
    IVT     Interface Verification Test
    IVT     Intervehicular Transfer
    IVTE    Integration and Verification Test Environment
    IWBS    Indirect Work Breakdown Structure
    IWG     Interface Working Group
    IWG     Investigator Working Group
    
    
    J
    
    J       Joule (SI Unit)
    J-BOSC	Joint Base Operations and Support Contract
    J/M     Jettison Motor
    JACEE   Japanese-American Cooperative Emulsion Experiment
    JACD    Joint Architectural Control Document
    JAD     Joint Assembly Demonstration
    JAEIC   Joint Atomic Energy Intelligence Committee
    JAN     Joint Army-Navy
    JANNAF  Joint Army, Navy, NASA, and Air Force
    JAS     Journal of Aerospace Science
    JAS     Journal of Atmospheric Science
    JB      Junction Box
    JBOSC	Joint Base Operations and Support Contract
    JCL     Job Control Language
    JCP     Joint Power Conditions
    JCT     Junction
    JEA     Joint Endeavor Agreement
    JED     Julian Ephemeris Data
    JELM    Japanese Experiment Logistics Module
    JEM     Japanese Element Module
    JEM     Japanese Experiment Module
    JES     Joint Environment Simulator
    JETS    Joint Electronics Type (Designation) System
    JETT    Jettison
    JGR     Journal of Geophysical Research
    JIR     Job Improvement Request
    JIS     Joint Integrated Simulation
    JO      Job Order
    JOC     Joint Operations Center
    JOD     Joint Occupancy Data
    JOD     Joint Occupancy Date
    JOFOC   Justification for Other Than Full and Open Competition
    JOIP    Joint Operations Interface Procedure
    JOP     Joint Operating Procedure
    JOP     Jupiter Orbiter Probe-Galileo
    JOR     Job Order Request
    JOV     Joint Venture
    JOVIAL  Joules Own Version International Algebraic Language
    JP      Jet Propellant
    JP      Jet Propulsion
    JPC     Joint Power Condition
    JPDRD   Joint Program Definition and Requirements Document
    JPIC    Joint Program Integration Committee
    JPL     Jet Propulsion Laboratory
    JPOC    JSC Payload Operations Center
    JPP     Joint Program Plan
    JRB     Joint Review Board
    JSA     Job Safety Analysis
    JSC     Lyndon B. Johnson Space Center (formerly MSC)
    JSCM    JSC Manual
    JSL     Jet Select Logic
    JSLWG   Joint Spacelab Working Group
    JST     Joint Systems Test
    JTA     Job Task Analysis
    JTG     Joint Training Group
    JU      Joint Use
    JULIE   Joint Utilization of Laser Integrated Experiments
    JURG    Joint Users Requirements Group
    
    K
    
    K       Kelvin
    K       Kilocycle
    K       One Thousand
    k       Kilo (1,000)
    K&H     Memory Time Value
    K-APM   KSC Automated Payloads Plan/Requirement
    K-APN   KSC Automated Payloads Notice
    K-APPS  KSC Automated Payloads Project Specification
    K-BAND  10,900 to 36,000 MCS
    K-CITEM KSC CITE Plan/Requirement
    K-DODM  KSC DOD Plan/Requirement
    K-DPM   KSC DOD Payloads Plan/Requirement
    K-DPN   KSC DOD Payloads Notice
    K-DPPS  KSC DOD Payloads Project Specification
    K-IUSM  KSC IUS Plan/Requirement
    K-IUSN  KSC IUS Notice
    K-IUSPS KSC IUS Project Specification
    K-MMSEM KSC MMSE Plan/Requirement
    K-MMSEN KSC MMSE Notice
    K-MMSEPS KSC MMSE Project Specification
    K-SLM   KSC Spacelab Plan/Requirement
    K-SLN   KSC Spacelab Notice
    K-SLPS  KSC Spacelab Project Specification
    K-SM    KSC Shuttle Management Document
    K-SPN   KSC Shuttle Project Notice
    K-SPS   KSC Shuttle Project Specification
    K-SSS   KSC Shuttle Project Station Set Specification
    K-STSM  KSC STS Plan/Requirement
    K-STSN  KSC STS Notice
    K-STSPS KSC STS Project Specification
    K/S     Kick Stage
    KAD     Kadena AB, Ryuku Islands (Deorb OPT Site)
    KAPL    KSC Approved Parts List
    KATE    Knowledge-Based Automatic Test Equipment (KSC's)
    KATS    Kennedy Avionics Test Set
    KAU     Kilo Accounting Unit
    KB      Keyboard
    KB      Kilobit
    KBAC    Kennedy Booster Assemblv Contractor
    KBIM    Keyboard Interface Module
    KBPS    Kilobits Per Second
    KBU     Keyboard Unit
    kc      Kilocycle
    kcal    Kilocalorie
    KCAS    Knots Calibrated Airspeed
    KCCS    Kennedy Complex Control System
    KCRT    Keyboard Cathode Ray Tube
    KCS     Keyboard Configuration Studies
    KDMS    Kennedy Data Management System(s)
    KDN     Kinetically Designed Nozzle
    KDP     Kennedy Documented Process
    KDT     Keyboard and Display Test
    KDU     Keyboard and Display Unit
    KEAS    Knots Equivalent Airspeed
    kg      Kilogram
    kgal/min Kilogallons Per Minute
    KHB     KSC Handbook
    kHz     Kilohertz
    KIAS    Knots Indicated Airspeed
    KICS	Kennedy Integrated Communications Services
    KIMS    Kennedy Inventory Management System
    KIP     Keyboard Input Processor
    KIS     Kitting Instruction Sheet
    KITE    Kinetic Isolation Tether Experiment
    klb     Kilopound
    km      Kilometer
    KLMRC   Kennedy Labor Management Relations Council
    KMI     KSC Management Instruction
    KMR     Kwajalein Missile Range
    KMS     K-Words X Millions of Seconds
    KN      Kitting Notice
    KN      KSC Notice
    KNO     Kano, Nigeria (Remote Site)
    KNPR    Kennedy NASA Procedural Requirements
    KOI     KSC Operation Instruction
    KOM     KSC Organizational Manual
    KOPS    Thousand of Operations per Second
    KPD     KSC Program Directive
    KPPMC   Kennedy Program Project Management Council
    KPPS    Kilopulses per Second
    KPRD    KSC Program Requirements Document
    KPS     Kilometers Per Second
    KSA     Ku-Band Single Access
    KSC     John F. Kennedy Space Center
    KSC     Kennedy Space Center
    KSCAP   Kennedy Space Center Area Permit
    KSDN    Kennedy Switched Data Network
    KSSS    KSC Station Set Specification
    KT      Kit
    KT      Knots
    KU      Keyboard Unit
    KUSP    Ku-Band Signal Processor
    KUSP    Ku-Band Single Processor
    kV      Kilovolt
    kVA     Kilovoltampere
    kW      Kilowatt
    kWh     Kilowatt Hours
    KYBD    Keyboard
    
    L
    
    L       Launch
    L       Launch or Landing Time
    L       Left
    L       Length
    L       Level
    L       Low
    L       Lumen
    L&C     Laboratory and Checkout
    L&D     Landing and Deceleration
    L&L     Launch and Landing
    L&S     Logistics and Support
    L&T     Laboratory and Test
    L-BAND  S-Band 390 to 1550 MHz
    L-L     Line-to-Line
    L-P     Low Pressure
    L/D     Length-to-Diameter
    L/D     Lift-to-Drag (Ratio)
    L/H     Local Horizontal
    L/O     Lift-off
    L/S     Load System
    L/S     Landing Site
    L/T     Load Test
    LO2     Liquid Oxygen
    LA      Launch Area
    LA      Lanthanum
    LA      Launch Abort
    LA      Launch Azimuth
    LA      Lightning Arrester
    LA      Launch Aft
    LA      Low Attitude
    LAAD    Los Angeles Aircraft Division (Rockwell)
    LACB    Landing Aids Control Building (SLF at KSC)
    LACIE   Large Area Crop Inventory Experiment
    LACIP   Large Area Crop Inventory Program
    LAGEOS  Laser Geodynamic Satellite
    LAGS    Launch Abort Guide Simulation
    LAIR    Liquid Air
    LAIU    Launch Abort Interface Unit
    LAN     Local Area Network
    LAP     Language Assistance Plan
    LAPS    Logistics Analysis and Provisioning System
    LAPS    Left Aft Propulsion System (Subsystem)
    LAR     Logistics Assessment Review
    LaRC    Langley Research Center (Hampton, VA)
    LARS    Laminar Angular Rate Sensor
    LARSSYAA  Laboratory for Application of Remote Sensing System for Aircraft Analysis
    LASCOT  Large Screen Color Television System
    LASV    Low Altitude Supersonic Vehicle
    LAT     Lateral
    LAT     Latch
    LAT     Large Angle Torque
    LAT     Lot Acceptance Test
    LAT     Latitude
    LATS    LDEF Assembly and Transportation System
    LB      Lower Brace
    LB      Low Bay
    LB      Load Bank
    LB      Launch Bus
    LB      Launch Boost
    lb      Pound
    LBDT    Low Bay Dolly Tug
    LBK     Left Bank
    LBL     Left Buttock Line
    LBM     Load Buffer Memory
    LBNPD   Lower Body Negative Pressure Device
    LBR     Low Bit Rate
    LC      Launch Complex
    LC      Launch Countdown
    LC      Launch Critical
    LC      Left Center
    LCA     Launch Control Amplifier
    LCA     Load Controller (Control) Assembly
    LCB     Least Common Bit
    LCC     Launch Commit Criteria
    LCC     Launch Control Center (KSC)
    LCC     Life Cycle Cost
    LCCD    Launch Commit Criteria Document
    LCD     Launch Countdown
    LCF     Low Cycle Fatigue
    LCG     Liquid Cooled Garment
    LCH     Latch
    LCH     Launch
    LCHTF   Low Cycle High Temperature Fatigue
    LCL     Local
    LCM     Least Common Multiple
    LCMS    Low Cost Modular Spacecraft
    LCO     MMC Uniform Central Number
    LCOM    Logic Control Output Module
    LCR     Low Cross Range
    LCS     Laser Communications Subsystem (System)
    LCS     Launch Control System
    LCS     List of Command Signals
    LCT     Launch Countdown
    LCU     Line Coupling Unit
    LCVG    Liquid Cooling and Ventilation Garment
    LCUG    Liquid Cooling Under Garment
    LD      Lateral Direction
    LD      Launch Director
    LD      Loading Dock
    LDB     Launch Data Bus
    LDB     Logistics Data Bank
    LDEC    Lunar Docking Events Controller
    LDEF    Long Duration Exposure Facility
    LDG     Landing
    LDIU    Launch Data Interface Unit
    LDMK    Landmark
    LDR     Large Deployable Reflector
    LDR     Low Data Rate
    LDS     Landing/Deceleration Subsystem
    LDS     Landing, Deservicing, and Safing
    LDS     Laser Docking Sensor
    LDS     Loads
    LDT     Linear Displacement Transducer
    LE      Leading Edge
    LE      Launch Escape
    LEA     Logistics Engineering Analysis (Analyses)
    LEB     Lower Equipment Bay
    LEC     Lockheed Electronics Company
    LED     Light Emitting Diode
    LEH     Launch/Entry Helmet
    LEM     Laboratory Environment Model
    LEM     Launch Escape Monitor
    LEO     Low Earth Orbit
    LER     Long Eye Relief (Optics)
    LeRC    Lewis Research Center (Cleveland, OH)
    LES     Launch Entry Suit
    LES     Launch Equipment Shop
    LES     Launch Escape Subsystem
    LESS    Leading Edge Structure Subsystem
    LESS    Leading Edge Subsystem
    LETF    Launch Equipment Exposure Facility
    LETF    Launch Equipment Test Facility (KSC)
    LF      Launch Facility
    LF      Launch Forward
    LF      Left Forward
    LF      Load Factor
    LF      Low Frequency
    LFAF    Low Frequency Accelerometer Flutter
    LFAM    Low Frequency Accelerometer Modes
    LFAP    Low Frequency Accelerometer Pogo
    LFC     Large Format Camera
    LFO     Low Frequency Oscillator
    LFOP    Landing and Ferry Operations Panel
    LFRR    Low Frequency Radio Range
    LG      Landing Gear
    LG      Length
    LGA     Low Gain Antenna
    LGIU    Laser Gyro Interface Unit
    LH      Left Hand
    LH2     Liquid Hydrogen
    LHA     Local Hour Angle
    LHC     Left Hand Circular
    LHCP    Left Hand Circular Polarization
    LHCP    Left Hand Circularly Polarized
    LHe     Liquid Helium
    LHP     Left Hand Panel
    LHS     Left Hand Side
    Li      Lithium
    LIB     Left Inboard
    LIC     Load Interface Circuit
    LID     Leadless inverted Device
    LID     Logistics Identification Document
    LIDAR   Laser-Radar
    LIE     Left Inboard Elevon
    LIM     Limit
    LIMRC   LRU Identification and Maintenance Requirements Catal
    LIMS    Logistics Inventory Management System
    LIN     Linear
    LIN     Liquid Nitrogen
    LINJET  Liquid Injection Electric Thruster
    LINS    Laser Inertial Navigation System
    LiOH    Lithium Hydroxide
    LIQ     Liquid
    LIS     Logistics Information System
    LK      Leak
    LK      Lock
    LL      Launch and Landing
    LL      Launch Left
    LL      Lever Lock
    LL      Long Lead
    LL      Long Line
    LL      Low Level
    LL      Lower Left
    LL      Lower Limit
    LLCF    Launch and Landing Computational Facilities
    LLI     Limited Life Item
    LLIL    Long Leadtime Items List
    LLOS    Landmark Line-of-Sight
    LLP     Launch and Landing Project
    LLPO    Launch and Landing Project Office
    LLS     Launch and Landing Site
    LLT     Long Leadtime
    LM      Left Mid
    LM      Long Module
    LMC     Lightweight MPESS Carrier
    LME     Launch Monitor Equipment
    LMF     Lower Mid-Fuselage
    LMG     Left Main Gear
    LMK     Landmark
    LMP     List of Measurement Points
    LMS     Load Measurement System
    LMS     Logistics Master Schedules
    LMSC    Lockheed Missiles and Space Corporation
    LN      Line
    LN2     Liquid Nitrogen
    LNCH    Launch
    LNDG    Landing
    LNG     Liquefied Natural Gas
    LO      Launch Operations
    LO      Local Oscillator
    LO      Lock-On
    LO2     Liquid Oxygen
    LOA     Landing Operations Area
    LOA     Launch Operations Area
    LOACS   Launch Operations Access Control System
    LOAP    List of Applicable Publications
    LOB     Left Outboard
    LOB     Line of Balance
    LOC     Localizer
    LOC     Location
    LOC     Launch Operations Complex
    LOCC    Launch Operations Control Center
    LOE     Left Outboard Elevon
    LOE     Level of Effort
    LOE     Line of Effort
    LOFAR   Low Frequency Acquisition and Ranging
    LOFO    Low Frequency Oscillation
    LOGO    Limit of Government Obligation
    LOI     Lunar Orbit Insertion
    LOL     Limit of Liability
    LOLI    Limited Operational-Life Items
    LON     Launch On Need
    LON     Longitude
    LON	LPS Operations Network
    LONG    Longitude
    LOR     Lunar Orbit Rendezvous
    LORA    Level of Repair Analysis
    LORAN   Long Range Navigation
    LOS     Lift-Off Simulator
    LOS     Line of Sight
    LOS     Loss of Signal
    LOS     Loss of Sync
    LOT     Lift-Off Time
    LOTO	Lockout/Tagout
    LOV     Limit of Visibility
    LOV     Loss of Visibility
    LOWG    Landing Operations Working Group
    LOX     Liquid Oxygen (LO2
    LP      Launch Pad
    LP      Liquid Propellant
    LP      Low Pressure
    LPD     Landing Point Designator
    LPD     Launch Procedure Document
    LPD     Low Profile Dolly
    LPDM    List of Physical Dimensions
    LPF     Low Pass Filter
    LPFT    LOPW Pressure Fuel Turboprop
    LPFTP   Low Pressure Fuel Turbopump
    LPG     Last Page Generator (Distribution List Used in All OMTs)
    LPG     Liquid Propellant Gun
    LPLWS   Launch Pad Lightning Warning System
    LPM     Lines per Minute
    LPOP    Low Pressure Oxidizer Turbopump
    LPOT    Low-Pressure Oxidizer Turbopump
    LPOTP   Low Pressure Oxidizer Turbopump
    LPOX    Low Pressure Oxygen
    LPR     Line Printer
    LPS     Launch Processing (Processor) System
    LPS     Liters Per Second
    LPS/CDS LPS/Central Data Subsystem
    LPTTL   Low Power Transistor-Transistor Logic
    LPW     Lumens per Watt
    LR      Landing Radar
    LR      Launch Right
    LR      Left Rudder
    LR      Lower Right
    LR/LD   Line Receiver/Line Driver
    LRECL   Logical Records of Fixed Length
    LRF     Liquid Rocket Fuel
    LRO     Large Radio Observatory
    LRR     Launch Readiness Review
    LRSI    Low Temperature Reusable Surface Insulation
    LRU     Line Replaceable Unit
    LRV     Long Range Video
    LRV     Launch Readiness Verification
    LS      Limit Switch
    LS      Launch Sequence
    LS      Landing Side
    LS      Left Side
    LS      Life Science
    LS/ST   Light Shield/Star Tracker
    LSA     Launch Services Agreement
    LSA     Logistics Support Analysis
    LSAH    Launch Site Accommodations Handbook
    LSAP    Launch Sequence Applications Program
    LSAR    Logistics Support Analysis Record
    LSB     Lower Side Band
    LSB     Least Significant Bit
    LSC     Linear Shaped Charge
    LSCA    Logistics Support Cost Analysis
    LSD     Low Speed Data
    LSD     Landing Ship Dock
    LSE     Launch Support Equipment
    LSE     Life Support Equipment
    LSF     Laboratory Simulation Facility
    LSFE    Life Sciences Flight Experiment
    LSI     Large Scale Integration
    LSID    Launch Sequence and Interlock Document
    LSM     Life Science Module
    LSMI    Logistics Support Management Information
    LSO     Landing Support Officer
    LSO     Large Solar Observatory
    LSP     Least Significant Portion
    LSPDF   Life Science Payloads Development Facility
    LSR     Launch Site Recovery
    LSR     Land Sea Rescue
    LSRM    Life Science Research Module
    LSS     Landing, Separation Simulator
    LSS     Life Support Subsystem
    LSSL    Life Sciences Space Laboratory
    LSSF    Life Sciences Support Facility
    LSSM    Launch Site Support Manager
    LSSP    Launch Site Support Plan
    LSSR    Landing Site Support Review
    LSSRC   Life Sciences Shuttle Research Centrifuge
    LSST    Launch Site Support Team
    LST     Large Space Telescope
    LST     Large Stellar Telescope
    LST     Launch Support Team
    LST     Liquid Storage Tank
    LST     Local Standard Time
    LSTE    Launch Site Transportation Equipment
    LSU     Life Support Umbilical
    LT      Lead Time
    LT      Left
    LT      Light
    LTA     Lower Torso Assembly
    LTD     Limited
    LTD     Lift-to-Drag
    LTG     Lighting
    LTG     Linear Tangent Guidance
    LTM     Lead Time Matrix
    LUB     Lubricate
    LUS     Liquid Upper Stage
    LUT     Launcher-Umbilical Tower
    LV      Launch Vehicle
    LV      Lift Vector
    LV      Limit Value
    LV      Load Vertical
    LV      Loading Valve
    LV      Low Voltage
    LVDC    Launch Vehicle Digital Computer
    LVDT    Linear Variable Differential Transformer
    LVDT    Linear Voltage Differential Transformer
    LVL     Level
    LVLH    Local Vertical/Local Horizontal
    LW      Launch Window
    LWD     Launch Window Display
    LWD     Left Wing Down
    LWG     Logistics Working Group
    LWHS    Light-Weight Headset
    LWR     Lower
    LWS     Lightning Warning System
    LWT     Launch Window Time
    LWT     Light Weight Tank (Shuttle-C ET)
    
    M
    
    M       Mach
    M       Maintainability
    M       Major Cycle
    M       Male
    M       Mandatory
    M       Manual
    M       Mass
    M       Matrix
    M       Mega
    M       Mercury
    M       Middle
    M       Million
    M       Missing (Data)
    M       Monitor (MON preferred)
    M       Number of Revolutions Required for the Rendezvous
    m       Meter
    M&C     Maintenance and Checkout
    M&C     Monitor and Control Panel
    M&F     Materials and Facilities
    M&M     Materials and Maintenance
    M&O     Maintenance and Operations
    M&P     Materials and Processes
    M&P     Materials and Processing
    M&R     Maintenance and Refurbishment
    M&R     Maintenance and Repair
    M&RF    Maintenance and Refurbishing Facility
    M&RO    Maintenance and Refurbishment Operations
    M+R     Maintenance and Refurbishment
    M+R     Maintenance and Repair
    M-      Time in Days Before Move Operations
    m-kg    Meter-Kilogram
    M-M-L-S Model-Modes-Loads-Stresses
    M/F     Maintenance Factor
    M/I     Minimum Impulse
    M/L     Maintenance Loop
    M/LR    Maintenance Loop Recorder
    M/P     Main Parachute
    M/R     Mixture Ratio (Fuel to Oxidizer)
    M/S     Measurement Stimuli
    M/SCI   Mission/Safety Critical Item
    M/U     Mockup
    M50     Mean of 1950 (Coordinate System)
    MA      Maintenance (STS)
    MA      Maintenance Ability
    MA      Martin Ablator
    MA      Master
    MA      Master Alarm
    MA      Material Authorization
    MA      Metabolic Analyzer
    MA      Middeck Act
    MA      Mike Amplifier
    MA      Missed Approach
    MA      Mission Analysis
    MA      Mission Assignment
    MA      Multiple Access
    mA      Milliampere
    MA&P    Maintenance Analysis and Planning
    MA&T    Manufacturing Assembly and Test
    MAA     Mathematical Association of America
    MAA     Maximum Authorized Altitude
    MAA     Mechanical Arm Assembly
    MAAB    Materials Application Advisory Board
    MAAR    Monthly Associate Administrator's Review
    MAB     Master Acquisition Bus
    MAB     Materials Advisory Board
    MAB     Materials Applications Board
    MAB     Mechanical Automation Breadboard
    MAB     Missile Assembly Building
    MAC     Main Display Console
    MAC     Maintenance Advisory Committee
    MAC     Maximum Allowable Concentration
    MAC     Maximum Concentration of Organics
    MAC     Mean Aerodynamic Chord
    MAC     Military Airlift Command
    MAC     Multiaccess Computer
    MACDS   Monitor and Control Display System
    MACE    Mechanical Antenna Control Electronics
    MACH    Machine
    MACH    Velocity Relative to the Speed of Sound
    MACI    Monitor, Access, and Control Interface
    MACO    Major Assembly Checkout
    MACRO   Merge and Correlate Recorded Output (Program)
    MAD     Madrid, Spain (STDN)
    MAD     Maintenance Analysis Data
    MADC    Multiplexer Analog to Digital Converter
    MADRE   Manufacturing Data Retrieval System
    MADS    Modeling and Analysis Data Set
    MADS    Modular Auxiliary Data Systems
    MAEP    Minimum Autoland Entry Point
    MAF     Manpower Authorization File
    MAF     Michoud Assembly Facility
    MAF     Mixed Amine Fuel
    MAG     Magazine
    MAG     Magnetic
    MAG     Magnitude
    MAGSAT  Magnetometer Satellite
    MAI     Machine-Aided Indexing
    MAIDS   Management Automated Information Display System
    MAIDS   Multipurpose Automatic Inspection and Diagnostic System
    MAIN    Maintenance
    MAINT   Maintenance
    MAIR    Manufacturing and Inspection Record
    MAJ     Major
    MAL     Malfunction
    MAL     Material Allowance List
    MAL     Mobile Airlock
    MALL    Malleable
    MAN     Manual
    MAN     Microwave Aerospace Navigation
    MANF    Manifold
    MAOT    Maximum Allowable Operating Time
    MAP     Maintenance Analysis Program
    MAP     Message Acceptance Pulse
    MAP     Mission Application Program
    MAP     Missed Approach Point
    MAPOLE  Magnetic Dipole Spark Transmitter
    MAPS    Measurement of Air Pollution from Satellites
    MAPS    Measurement of Atmospheric Pollution from Satellites
    MAR     Maintenance Action Request
    MAR     Maintenance and Refurbishment
    MAR     Memory Address Register
    MARGO   Manned Apollo Recovery Ground Optics
    MARS    Martin Automatic Reporting System
    MARS    Modular Airborne Recorder System
    MASDC   Military Aircraft Storage and Disposition Center
    MAT     Matrix
    MAT     Meteorological Atmospheric Turbulence
    MAT     Multiple Actuator Test
    MATCO   Materials Analysis, Tracking, and Control
    MATE    MDM Application Test Environment
    MATL    Material
    MAU     Million Accounting Units
    MAUS    Messenschafteliche Autonome Experiment Unter Schewerelosigkeit
    MAX     Maximum
    MAXCO   Maximum Dynamic Pressure
    MB      Main Bus
    MB      Management Baseline
    MB      Millibar
    MB/S    Megabits per Second
    MBAC    Marshall Booster Assembly Contractor
    mbar    Millibar
    MBB     Messerschmitt-Boklow-Blahn
    MBC     Maximum Breathing Capacity
    MBCS    Motion-Base Crew Station (SMS)
    MBFP    Manufacturing Build and Flow Plan
    MBI     Multibus Interface
    MBK     Medications and Bandage Kit
    MBL     Mobile Unit (TACAN Station)
    MBO     Management by Objective
    MBPS    Megabits Per Second
    MBPS    Million Bits Per Second
    MBS     Mobile Base System
    MBV     Main Base Visit
    MC      Memory Configuration
    MC      Midcourse Correction Maneuver
    MC      Mission Capability
    MC      Mission Completion/Continuation
    MC&C    Measurement, Command, and Control
    MC&W    Master Caution and Warning
    MCA     Master Control Assembly
    MCA     Maximum Crossing Altitude
    MCA     Monitoring and Control Assembly
    MCA     Motor Control Assembly
    MCA     Multichannel Analyzer
    MCBF    Mean Cycle between Failures
    MCC     Main Combustion Chamber
    MCC     Mission Control Center (JSC)
    MCC     Motor Control Center (JSC)
    MCC-DOD Mission Control Center-DOD
    MCC-H   Mission Control Center-Houston
    MCC-K   Mission Control Center-Kennedy
    MCC-NASA  Mission Control Center-NASA
    MCCC    Mission Control and Computing Center
    MCCS    Mission Control Center Simulation (System)
    MCDS    Maintenance Control and Display System
    MCDS    Multifunction CRT Display System
    MCDU    Multifunction CRT Display Unit
    MCE     Mechanism Control Electronics
    MCF     Maintenance and Checkout Facility
    MCF     Major Component Fail
    MCF     Mission Control Facility
    MCIU    Manipulator Controller Interface Unit
    MCIU    Master Control and Interface Unit
    MCIU    Mission Control and Interface Unit
    MCL     Mass Change Log
    MCL     Master Configuration List
    MCLT    Maximum Cruise Level Thrust
    MCM     MADS Control Module
    MCN     Master Change Notice
    MCO     Mission Control Center
    MCOP    Mission Control Operations Panel
    MCP     Master Change Proposal
    MCP     Master Computer Program
    MCP     Materials Control Plan
    MCP     Measurements Control Procedure
    MCP     Mission Control Programmer
    MCP     Monitoring and Control Panel
    MCPC    Manipulator Controller Power Conditioner
    MCPS    Major Cost Proposal System
    MCR     Master Change Record
    MCS     Maintenance and Checkout Station
    MCS     Measurements Calibration System
    MCT     Maximum Climb Thrust
    MCT     Mission Control Table
    MCU     Master Control Unit
    MCU     Mission Control Unit
    MCVP    Materials Control and Verification Program
    MCW     Modulated Continuous Wave
    MD      Biomedical Office (KSC Directorate)
    MD      Malfunction Detection
    MD      Manual Direct
    MD      Manual Disconnect
    MD      Master Dimension
    MD      Microdot
    MD      Mission Director
    MDA     Main Distribution Assembly
    MDA     Maintainability Design Approach
    MDA     Middeck Assembly (FDF)
    MDA	Missile Defense Agency
    MDA     Motor Drive Amplifier
    MDA     Multiple Docking Adapter
    MDAC    McDonnell Douglas Astronautics Company
    MDAR    Malfunction Detection, Analysis, and Recording
    MDAS    Meteorological Data Acquisition System
    MDAS    Mission Data Acquisition System
    MDB     Mission Data Book
    MDC     Main Display Console
    MDC     Mission Director Center
    MDC     Mission Duty Cycle
    MDCA    Main Distribution Control Assembly
    MDCS    Maintenance Data Collection System
    MDCS    Malfunction Display and Control System
    MDCS    Master Digital Command System
    MDCS    Material Data Collection System
    MDD     Mate/Demate Device
    MDDS    Material Directory Data Sheet
    MDE     Mission Dependent Equipment
    MDE     Mission Dependent Experiment
    MDE     Modular Display Electronics
    MDF     Main Distribution Frame
    MDF     Mild Detonating Fuse
    MDF     Manipulator Development Facility
    MDF     Mating/Demating Facilities
    MDL     Master Data Library
    MDM     Manipulator Deployment Mechanism
    MDM     Medical Monitor
    MDM     Multiplexer/Demultiplexer
    MDR     Maintenance Demand Rate
    MDR     Major Design Review
    MDR     Minor Discrepancy Repair
    MDR     Mission Data Reduction
    MDR     Missing Data Report
    MDR     Monthly Director's Review
    MDRD    Mission Data Requirements Document
    MDRS    Manufacturing Data Retrieval System
    MDRS    Mission Data Retrieval System
    MDS     Malfunction Detection System
    MDS     Management Data System
    MDS     Master Development Schedule
    MDS     Minimum Discernible Signal
    MDS     Minimum Discernible System
    MDS     Mission Development Simulator
    MDS     Motion Detection System
    MDSD    Mate/Demate Stiffleg Derrick
    MDT     Maintenance Demand Time
    MDT     Mean Detonating Time
    MDT     Mean Down Time
    MDT     Measurement Descriptor Table
    MDT     Mountain Daylight Time
    MDTSCO  McDonnell Douglas Technical Services Company
    ME      Main Engine
    ME      Management Engineering
    ME      Miscellaneous Equipment
    MEA     Main Electronics Assembly
    MEA     Maintenance Engineering Analysis
    MEA     Materials Experiment Assembly
    MEAR    Maintenance Engineering Analysis Request
    MEAS    Measuring, Measurement
    MEB     Main Electronics Box
    MEBO    Main Engine Burnout
    MEC     Engine Mounted Computer
    MEC     Main Engine Controller
    MEC     Master Event Controller
    MEC     Materials Experiment Carrier
    MEC     Mission Events Controller
    MECA    Main Engine Controller Assembly
    MECCA   Master Electrical Common Connector Assembly
    MECF    Main Engine Computational Facilities
    MECH    Mechanical
    MECO    Main Engine Cutoff
    MECR    Maintenance Engineering Change Request
    MED     Manual Entry Device
    MED     Medical
    MED     Medium
    MEDEA	Material Science Experiment Double Rack for Experiment Modules and Apparatus
            (Spacelab D-1 Experiment)
    MEDICS  Medical Information Computer System
    MEDS	Multifunction Electronic Display Subsystem (glass cockpit)
    MEE     Mission Essential Equipment
    MEG     Megohm
    MEI     Master Inspection Item
    MEIG    Main Engine Ignition
    MEIT    Multi Element Integration Testing
    MEIU    Main Engine Interface Unit
    MEL     Master Equipment List
    MEL     Minimum Equipment List
    MEL	Modular Electromagnetic Levitator
    MELEO	Material Exposure in Low Earth Orbit
    MELI    Master Equipment List Index
    MELI    Minimum Equipment List Index
    MEM     Meteoroid Exposure Module
    MEM     Module Exchange Mechanism
    MEMS	MicroElectroMechanical Systems
    MEOP    Maximum Expected Operating Pressure
    MEP     Main Engine Propellant
    MEP     Main Entry Point
    MEP     Management Engineering Program
    MEP     Mean Effective Pressure
    MEP     Minimum Entry Point
    MEQA&P  Mission, Environmental, Quality Assurance & Policy
    MER	Mars Exploration Rover
    MER     Meridian
    MER     Mission Evaluation Room
    MERB    Materials and Engineering Review Board
    MERL    Materials Engineering Research Laboratory
    MERL    Materials Equipment Requirement List
    MERSAT  Meteorology and Earth Observation Satellite
    MERU    Milliearth Rate Unit
    MES     Main Engine Start
    MES     Mated Elements Simulator
    MES     Mated Events Simulator
    MES     Mission Events Sequence
    MESA    Marshall Engineers and Scientists Association
    MESA    Miniature Electrostatic Accelerometer
    MESA    Modular Equipment Stowage Assembly
    MESA    MSFC Engineering Support Area
    MESC    Master Events Sequencer Controller
    MESSENGER  Mercury Surface, Space ENvironment, GEochemistry and Ranging 
    MET     Master Events Timer
    MET     Meteorological
    MET     Mission Elapsed Time
    MET     Mission Events Timer
    META    Megachannel Extraterrestrial Assay
    METRO   Meteorology
    METVC   Main Engine Thrust Vector
    MEWG    Maintenance Engineering Working Group
    MF      Midfuselage
    MF      Mate and Ferry
    MF      Major Function
    MF      Master Frame
    MF      Medium Frequency (300 to 3000 kHz)
    MF      Middeck Forward
    MFA     Manned Flight Awareness
    MFBP    Manufacturing Flow and Building Plan
    MFC     Multiple Flight Computer
    MFC     Multiple Flight Controller
    MFD     Main Feed
    MFD     Malfunction Detection
    MFE     Mid Frequency Executive
    MFF     MDM Flight Forward
    MFG     Major Functional Group
    MFG     Manufacturing
    MFMR    Multifrequency Microwave Radiometer
    MFO     Major Function Overlay
    MFR     Manipulator Foot Restraint
    MFR     Multifunctional Review
    MFR     Maximum Flight Rate
    MFR     Multifunctional Receiver
    MFT     Mean Flight Time
    MFTAD   Master Flight Test Assignment Document (JSC)
    MFV     Main Fuel Valve
    MG      Middle Gimbal (YAW)
    MG      Mobile Generator
    Mg      Magnesium
    mg      Milligram
    MGA     Middle Gimbal Angle
    MGC     Manual Gain Control
    MGE     Maintenance Ground Equipment
    MGMT    Management
    MGR     Manager
    MGSE    Mechanical Ground Support Equipment
    MGT     Major Ground Test
    MGVT    Mated Ground Vibration Test
    MHA     Multiple Headset Adapter
    MHC     Manipulator Hand Controller
    MHD     Multihead Disc
    MHE     Material Handling Equipment
    MHF     Medium High Frequency
    MHSC    Manipulator Handset Controller
    MHW     Multihundred Watt
    MHz     Megahertz (Megacycles per Second)
    MI      Management Information
    mi      Mile
    MIA     Mission Implementation Agreement
    MIA     Multiflex Interface Adapter
    MIA     Multiplexer Interface Adapter
    MIB     Master Interconnect Board
    MIC     Management Information Center
    MICIS   Material Information Control and Information System
    MICOM   Missile Command (Army)
    MICS    Management Information and Control System
    MID	Maximo/Documentum Interface
    MID     Midbody
    MIE     Mechanical Integration Engineer
    MIL     Military
    MIL     GSFC Spaceflight Tracking and Data Network Station
    MILA    Merritt Island Launch Area
    MILS    Missile Impact Location System
    MILSTRIP  Military Standard Requisition and Issue Procedure
    MIMOSA  Mission Modes and Space Analysis
    MIMS    Medical Information Management System
    MIN     Minimum
    min     Minute
    MINW    Master Interface Network
    MIO     Management Integration Office
    MIOS    Multi-IMU Operation System
    MIP     Modification Instruction Package
    MIP     Mandatory Inspection Point
    MIP     Minimum Impulse Pulse
    MIP     MMU Integration Plan
    MIPR    Military Intergovernmental Purchase Request
    MIPS    Merritt Island Press Site
    MIR     Malfunction Investigation Report
    MIR     Mirror
    MIS     Management Information System
    MIS     Mission Information Subsystem
    MISC    Miscellaneous
    MISS    Mission
    MISSE   Materials International Space Station Experiment
    MIT     Massachusetts Institute of Technology (CSDL)
    MIT     Master Instruction Tape
    MITS    Marshall Integrated Telecommunications System
    MITTS   Mobile Igor Tracking Telescope System
    MIU     MPE Interface Unit
    MIU     Multiplex Interface Unit
    MIUL    Materials Identification and Usage List
    MIUS    Modular Integrated Utility Systems
    MJ      Mechanical Joint
    MJCA    Midbody Jettison Control Assembly
    MJS     Manipulator Jettison System (Subsystem)
    MK      Mark
    MKTI    Mission Kit Technical Instruction
    ML      Middeck Left
    ML      Mobile Launcher
    ML      Mold Line
    ML PED  Mobile Launcher Pedestal
    MLA     MDM Launch Aft
    MLA     Monochrome Lens Assembly
    MLB     Multilayer Board
    MLC     Mobile Launcher Computer
    MLF     MDM Launch Forward
    MLG     Main Landing Gear
    MLGS    Microwave Landing Guidance System
    MLI     Multilayer Insulation
    MLL     MDM Launch Left
    MLP     Mobile Launch (Launcher) Platform
    MLR     MDM Launch Right
    MLR     Monodisperse Latex Reactor
    MLRS	Monodisperse Latex Reactor System
    MLS     Microwave Landing System
    MLW     Maximum Landing Weight
    MLX	Merritt Island, FL (STDN Site, Second Antenna)
    MM      Main Memory
    MM      Main Module
    MM      Major Mode
    MM      Man-Month
    MM      Mass Memory
    MM      Math Model
    MM      Mission Manager
    mm      Millimeter
    MMA     Mass Memory Assembly
    MMACS   Maintenance Management and Control System
    MMACS   Maintenance, Mechanical Arm, and Crew System Engineer
    MMAG    Martin Marietta Astronautics Group
    MMAS    Material Management Accounting (Accountability) System
    MMC     Martin Marietta Corporation
    MMC     Mid Motor Controller
    MMC     Mission Management Center
    MMCA    Midbody Motor Control Assembly
    MMCL    Master Measurement and Control List
    MMDB    Mass Memory Data Base
    MMDB    Master Measurement Data Base
    MMDF    Mission Model Data File
    MMES    MSFC Mated Element Systems
    MMH     Maintenance Man-Hour
    MMH     Monomethylhydrazine
    MMH     Monomethyl hydrazine
    MML     Master Measurement(s) List
    MMLS    Model-Modes-Loads-Stresses
    MMOS    Multimode Optical Sensor
    MMPSE   Multiuse Mission Payload Support Equipment
    MMS     Mission Modular Spacecraft
    MMS     Modular Multiband Scanner
    MMS     Multimission Modular Spacecraft
    MMSE    Multiuse Mission Support Equipment
    MMT     Mass Memory Test
    MMT     Mission Management Team
    MMU     Manned Maneuvering Unit
    MMU     Mass Memory Unit
    MN      Main
    MNA,B,C Main Bus A, B, or C
    MNVR    Maneuver
    MO      Major Objective
    MO      Manned Orbiter
    MO      Manual Orientation
    MO      Manufacturing Order
    MO      Mars Observer
    MO      Master Oscillator
    MO      Middeck Overhead
    MO      Mission Operations
    MO      Move
    Mo      Molybdenum
    MOA     Make on Arrival
    MOA     Memorandum of Agreement
    MOA     Minute-of-Angle
    MOAR    MPLM Overhead Access Rig
    MOC     Marine Operation Center
    MOC     Missions Operations Center
    MOC     Mission Operations Computer
    MOCF    Mission Operations Computational Facilities
    MOCR    Mission Operations Control Room
    MOCS    Multichannel Ocean Color Sensor
    MOCV    Manual O2 Control Valve
    MOD     Mission Objectives Document
    MOD     Mission Operations Directorate
    MOD     Modification
    MOD     Modify
    MOD     Modulation, Modulator
    MOD     Module, Modular
    MODART  Methods of Defeating Advanced Radar Threats
    MODB    Master Object Data Base
    MODEM   Modulator-Demodulator
    MODLAN  Mission Operations Division Local Area Network
    MODS    Mission Oerations and Data System
    MODS    Modifications
    MOF     Manned Orbital Flight
    MOL     Molecular
    MOM     Mission Operations Manager
    MOM     Moment
    MON     Monitor
    MOP     Mission Operations Plan
    MOPI    Max Rate Output Initiator
    MOPR    Mission Operations Planning Review
    MOPR    Mission Operations Planning Room
    MOPS    Military Operations Phone System
    MOPS    Mission Operations Planning System
    MOR     Manufacturing Operation Record
    MOR     Mission Operations Record
    MORD    Medical Operations Requirements Document
    MORD    Mission Operations Requirements Document
    MORT    Management Oversight and Risk Tree
    MOS     Metal Oxide on a Substrate
    MOS     Metal Oxide Semiconductor
    MOS     Mission Operations System
    MOSPO   Mobile Satellite Photometric Observatory
    MOT     Motor
    MOU     Memorandum of Understanding
    MOV     Main Oxidizer Valve
    MOVA    Main Oxidizer Valve Actuator
    MOW     Mission Operations Wing
    MOWG    Mission Operations Working Group
    MP      Management Package
    MP      Mass Properties
    MP      Measuring Point
    MP      Medium Pressure
    MP      Melting Point
    MP      Meteorology Panel
    MP      Mission Planner
    MP      Mod Package
    MP&C    Maintenance Planning and Control
    MPA     Mass Processing Analysis
    MPAD    Mission Planning and Analysis Division (JSC)
    MPB     Maintenance Parts Breakdown
    MPC     Manual Pointing Controller
    MPC     Memory Protection Check
    MPC     Meteorological Prediction Center
    MPC     Mid Power Controller
    MPC     Midbody Pyro Controller
    MPCA    Mid Power Controller Assembly
    MPD     Main dc Power Distributor Assembly
    MPD     Maximum Permissible Dose
    MPE	Mission Peculiar Experiment
    MPESS   Mission Peculiar Experiment Support Structure
    MPG     Multipoint Grounding
    MPG     Multiple Point Ground
    MPGHM   Mobile Payload Ground Handling Mechanism
    MPHE    Material and Personnel Handling Equipment
    MPI     Mission Payload Integration
    MPIIN   Modification Procurement Instrument Identification Number
    MPIO    Mission Payload Integration Office
    MPL     Maintenance Parts List
    MPL     Manipulation Positioning Latches
    MPL     Mechanical Parts List
    MPL     Minimum Power Level (65 percent)
    MPLM    Multi-Purpose Logistics Module
    MPLN    Maintenance Planning (Data Base)
    MPM     Manipulator Positioning Mechanism
    MPM     Materials Properties Manual
    MPMP    Mass Properties Management Plan
    MPMSE   Multiuse Payload and Mission Support Equipment
    MPP     Material Processing Procedure
    MPPSE   Multipurpose Payload Support Equipment
    MPR     Maintainability Problem Report
    MPR     Management Program Review
    MPR     Mockup Purchase Request
    MPS     Main Propulsion System (Subsystem)
    MPS     Master Program Schedule
    MPS     Material Processing Specification
    MPS     Material Processing System
    MPS     Materials Processing in Space
    MPS     Megabits per Second
    MPS     Mission Planning System
    MPS     Modular Power System
    MPSR    Mission Profile Storage and Retrieval
    MPSR    Multipurpose Support Room
    MPSS    Main Parachute Support Structure
    MPSS    Mission Planning and Scheduling System
    MPSS    Multiple Payload Support Structure
    MPST    Multipurpose Support Team
    MPT     Main Propulsion Test
    MPTA    Main Propulsion Test Article
    MPTF    Main Propulsion Test Facility
    MPTP    Main Propulsion Test Program
    MPTS    Multipurpose Tool Set
    MPVA    Main Propellant Valve Actuator
    MR      Main Ring
    MR      Master Reset
    MR      Material Review
    MR      Mission Report
    MR      Mixture Ratio
    MRA     Main Ring Assembly
    MRA     Mechanical Readiness Assessment
    MRB     Material Review Board
    MRC     Material Review Crib
    MRC     Measurement Requirements Committee
    MRCR    Measurement Requirement Change Request
    MRD     Mission Requirements Document
    MRD     Material Review Disposition
    MRDR    Material Review Disposition Record
    MRF     Maintenance Responsibility File
    MRF     Maximum Retarding Force
    MRF     Measurements/Stimuli Request Form
    MRI     Measurement Requirements and Interface
    MRI     Moderate Resolution Imager
    MRIR    Medium Resolution Infrared Radiometer
    MRL     Manipulator Retention Latches
    MRL     Manipulator Retention Lock
    MRL     Material Requirements List
    MRR     Mission Reconfiguration Request
    MRS     Management Review System
    MRTC    Multiple Real-Time Commands
    MS      Machine Screw
    MS      Machine Steel
    MS      Man System
    MS      Margin of Safety
    MS      Mass Spectrometer
    MS      Master Switch
    MS      Material Specification
    MS      Materials Science
    MS      Mating Sequence and Control
    MS      Milestone
    MS      Military Standard (Parts Designation)
    MS      Mission Specialist
    MS      Mission Station
    MS      Multistring
    ms      Millisecond
    MS/MS   Material Science and Manufacturing in Space
    MSA     Minimum Surface Area
    MSA     Material Service Area
    MSA     MSA-1
    MSAD    Materials Summary Acceptance Document
    MSAT    Multiflow Schedule Assessment Team
    MSB     Most Significant Bit
    MSBLS   Microwave Scanning Beam Land Station
    MSBLS   Microwave Scanning Beam Landing System
    MSBLS-GS  MSBLS Ground Station
    MSC     Manned Spacecraft Center (changed to JSC)
    MSC     Master Sequence Controller
    MSC     Materials Service Center
    MSC     Military Sealift Command
    MSC     Mobile Servicing Center
    MSC     Moding Sequencing and Control
    MSCC    Manned Systems Control Center
    MSCI    Mission Scientist
    MSCR    Measurement/Stimuli Change Request
    MSD     MARS Supplemental Data
    MSDS    Material Safety Data Sheet(s)
    MSDS    Multispectral Scanner and Data System
    MSE     Maintenance Support Equipment
    MSE     Measuring and Stimuli Equipment
    MSE     Mechanical Support Equipment
    MSE     Medical Support Equipment
    MSE     Mission Staff Engineer
    MSEC    Master Separation Events Controller
    msec    Millisecond (ms preferred)
    MSF     Maintenance Source File
    MSF     Manned Space Flight
    MSFC    George C. Marshall Space Flight Center
    MSFC    Marshall Space Flight Center
    MSFN    Manned Space Flight Network
    MSFP    Manned Space Flight Program
    MSG     Mechanical Subsystem Group
    MSG     Message
    MSG     Mission Support Group
    MSI     Maintenance Significant Items
    MSI     Medium Scale Integration
    MSIA    Multispectral Image Analyzer
    MSID    Measurement Stimulation identification
    MSK     Manual Select Keyboard
    MSL     Missile
    MSL     Mechanical System(s) Laboratory
    MSL     Mean Sea Level
    MSLD    Mass Spectrometer Leak Detector
    MSM     Manned Support Module
    MSN     Mission
    MSO     Model for Spare(s) Optimization
    MSOB    Manned Spacecraft Operations Building (O&C preferred)
    MSOCC   Multisatellite Operations Control Center
    MSOIN   Minor Subcontractor or IDWA Notification
    MSR     Module Support Rack
    MSS     Maintenance Status System
    MSS     Manufacturers Standardization Society
    MSS     Mechanical Support Systems
    MSS     Mission Specialist Staton
    MSS     Mission Status Summary
    MSS     Mobile Service Structure
    MSS     Multispectral Scanner System
    MSSTA   Multispectra Solar Telescope Array
    MST     Measurement Status Table
    MST     Mission Sequence Test
    MST     Mobile Service Tower
    MST     Module Service Tool
    MST     Module Systems Trainer
    MST     Mountain Standard Time
    MSTR    Master
    MSU     Mass Storage Unit
    MSU     Measuring Stimuli Units
    MSV     Monitored Sine Vibration (Test)
    MSVP    Master Shuttle Verification Plan
    MSW     Microswitch
    MSWG    Materials Science Working Group
    MT      Magnetic Tape
    MT      Master Timer
    MT      Master Tool
    MT      Maximum Torque
    MT      Mean Time
    MT      Mechanical Technician
    MT      Metering Truss
    MT      Mission Time
    MT      Mission Trajectory
    MT      Mobile Transporter
    MT      Mount
    MT      Mountain Time
    MTA     Magnetic Torquer Assembly
    MTA     Maintenance Task Analysis
    MTA     Major Test Article
    MTA     Marshall Trowelable Ablator
    MTA     Mass Thermal Analysis
    MTB     Materials Testing Branch
    MTBD    Mean Time between Demand
    MTBF    Mean Time between Failure
    MTBM    Mean Time between Maintenance
    MTBMA   Mean Time between Maintenance Action
    MTBR    Mean Time between Replacement
    MTC     Man-Tended Capability
    MTC     Manual Traffic Control
    MTC     Master Thrust Control
    MTC     Master Thrust Controller
    MTC     Mission and Traffic Control
    MTCA    Monitor and Test Control Area
    MTCU    Magnetic Tape Control Unit
    MTD     Mounted
    MTDSK   Magnetic Tape Disk
    MTE     Multisystem Test Equipment
    MTE     Maintenance Test Equipment
    MTEC    Maintenance Test Equipment Catalog
    MTEE    Electrical Maintenance Test Equipment
    MTEEC   Electronic Maintenance Test Equipment
    MTEF    Fluid Maintenance Test Equipment
    MTEM    Maintenance Test Equipment Module
    MTEM    Mechanical Maintenance Test Equipment
    MTEO    Optical Maintenance Test Equipment
    MTF     Mississippi Test Facility (now NSTL)
    MTFO    Modular Training Field Option
    MTG     Mounting
    MTGP    Monitor Table Generator Program
    MTGW    Maximum Total Gross Weight
    MTK     Mechanical Time Keeping
    MTL     Material
    MTL     Main Transfer Line
    MTLP    Monitor Table Listing Program
    MTM     Methods Time Measurement
    MTO     Modification Task Outline
    MTO     Magnetic Tape Operator
    MTO     Master Timing Oscillator
    MTO     Maximum Time Out
    MTO     Mission, Task, Objective
    MTOGW   Maximum Takeoff Gross Weight
    MTOW    Maximum Takeoff Weight
    MTP     Master Test Plan
    MTP     Manufacturing Technical Procedure
    MTP     Mission Test Plan
    MTR     Motor
    MTR     Magnetic Tape Recorder
    MTS     Metric Time System
    MTS     Master Timing System
    MTS     Magnetic Tape Station (System)
    MTT     Maximum Touch Temperature
    MTTA    Mean Time to Accomplish
    MTTE    Mean Time to Exchange
    MTTF    Mean Time to Failure
    MTTFF   Mean Time to First Failure
    MTTR    Mean Time to Repair
    MTU     Magnetic Tape Unit
    MTU     Master Timing Unit
    MTU     Mobile Training Unit
    MTVC    Manual Thrust Vector Control
    MTW     Maximum Taxi Weight
    MU      Master Unit
    MU      Mobile Unit
    MU      Mockup
    MU      Multiple Unit
    MUA     Material(s) Usage Agreement
    MUA     Maximum Usable Altitude
    MUF     Maximum Usable Frequency
    MULE    Multi-Use Lightweight Equipment
    MULT    Multiple
    MULT    Multiply
    MUM     Mass Memory Unit Manager
    MUMS    Multiple Use Marc System
    MUR     Manpower Utilization Report
    MUSAT   Canadian Government Satellite
    MUSS    Module Utility Support Structure
    MUX     Multiplex, Multiplexer
    MV      Manual Valve
    MV      Manufacturing Verification
    mV      Millivolt
    MVA     Main Valve Actuator
    MVA     Megavolt Ampere
    MVAS    Multipurpose Ventricular Actuating System
    MVC     Manual Volume Control
    MVC     Master Volume Control
    MVF     Manned Vertical Flight
    MVGVT   Mated Vertical Ground Vibration Test
    MVI     Microgravity Vestibular Investigation
    MVM     Mariner Venus/Mercury
    MVP     Master Verification Plan
    MVR     Maneuver
    MVS     Middle Value Select
    MVS     Multiple Virtual Storage
    MVT     Mission Verification Test
    MW      Man Week
    MW      Microwave
    mW      Milliwatt
    MWB     Master Work Book
    MWG     Maintenance Analyzer Working Group
    MWP     Maximum Working Pressure
    MWPE    Mental Workload and Performance
    MWPR    Monthly Work Package Report
    MWR     Mean Width Ratio
    MWS     Molecular Wake Shield
    MWV     Maximum Working Voltage
    MX      Multiplex
    MY      Man Year
    MYTA    Maintainability Task Analyses
    MYVAL   Maintainability Evaluation
    MZFW    Maximum Zero Fuel Weight
    
    N
    
    N       Neutrons
    N       Newton
    N       North
    N2      Nitrogen
    N2H4    Hydrazine
    N2HO4   Nitrogen Peroxide
    N2O4    Nitrogen Tetroxide
    N&G     Navigation and Guidance (G&N preferred)
    N/A     Next Assembly
    N/A     Not Applicable
    N/B     Narrow Band
    N/C     Non-Concur
    N/C     Normally Closed
    N/C     Nose Cone
    N/C     Not Critical
    N/C     Numerical Control
    N/D     Need Date
    N/O     Normally Open
    N/P     Not Provided
    N/W     Network
    NA      Next Action
    NA      Not Applicable
    NAAL    North American Aerodynamic Laboratory (Wind Tunnel)
    NAC     Nacelle
    NACA    National Advisory Committee for Aeronautics
    NAEC    Naval Air Engineering Center
    NAFIS   NASA Accounting and Financial Information Center
    NAICS   North American Industry Classification System
    NAM     National Association Of Manufacturers
    NAOO    National Oceanic and Atmospheric Administration
    NAP     Navigation Analysis Program
    NAR     Numerical Analysis Research
    NARC    North American Rockwell Corporation
    NARS    National Archives and Record Services
    NAS     National Academy of Sciences
    NAS     National Aircraft Standard
    NAS     Naval Air Station
    NASA    National Aeronautics and Space Administration
    NASCAD  NASA Computer Aided Design
    NASCOM  NASA Communications (Network)
    NASDA   National Space Development Agency (of Japan)
    NASP    National Aerospace Plane
    NASTRAN NASA Structural Analysis
    NATF    Naval Air Test Facility
    NATL    National
    NAV     Navigate, Navigation
    NAVAID  Navigation Aid
    NAVDAD  Navigationally Derived Air Data
    NAVEX   Navigation Experiments (Spacelab D-1 Experiment)
    NAVPOOL Navigation Parameter Common Pool
    NAVSAT  Navigation Satellite
    NAVSTAR Navigational Star
    NB      Narrow Band
    NB      Navigation Base
    NB      Neutral Buoyancy
    NB      Nitrogen Base
    NB      No-Bias (Relay)
    Nb      Niobium
    NBF     Neutral Buoyancy Facility
    NBL     Neutral Buoyancy Laboratory
    NBS     National Bureau of Standards
    NBS     Neutral Buoyancy Simulator
    NBT     Neutral Buoyancy Trainer
    NC      National Course
    NC      No Change
    NC      No Comment
    NC      Noise Criteria
    NC      Normal Corrective Maneuver
    NC      Normally Closed
    NC      Numerical Control
    NC1     Nominal Correction 1 (Phasing Maneuver)
    NCAR    National Center for Atmospheric Research
            (National Science Foundation Research Center)
    NCC     NASA Class Code
    NCC     Network Control Center (GSFC)
    NCC     Nominal Corrective Combination (Maneuver)
    NCC     Normal Corrective Combination (Maneuver)
    NCFI    North Carolina Foam Insulation
    NCGS    Nuclear Criteria Group Secretary
    NCI     Phasing Maneuver
    NCIU    Network Common Interface Unit
    NCOS    National Commission on Space
    NCR     No Calibration Required
    NCR     Nonconformance/Failure Report
    NCS     Near Infrared Camera & Multi-Object Spectrometer (NICMOS) Cooling System
    NCS     Nutation Control System
    ND      NASA Document
    Nd      Neodymium
    NDE     Nondestructive Evaluation
    NDI     Nondestructive Inspection
    NDT     Nondestructive Test
    NDTF    Nondestructive Test Facility
    NDTL    Nondestructive Test Laboratory
    NEA     Noise Equivalent Angle
    NEB	Network Engineering Branch
    NEBA    NASA Employee Benefit Association
    NEC     National Electrical Code
    NEC     Nippon Electric Company
    NEEDS   NASA End-To-End Data System
    NEG     Negative
    NEMS    NASA Equipment Management System
    NEO	Near-Earth Object
    NEP     Normal Entry Point
    NEPA    National Environmental Protection Act
    NESC    NASA Engineering and Safety Center
    NESC    National Electrical Safety Code
    NESR    Natural Environment Support Room
    NET     NASA Employee Team
    NET     Network (N/W preferred)
    NET     No Earlier Than
    NETCOM  Network Communications
    NEWMAST National Education Workshop for Math and Science Teachers
    NEXT    NASA Exploration Team
    NEXUS   NASA Engineering Extendible United Software System
    NF      Natural Flood
    NF      Noise Figure
    NFCS    Nuclear Forces Communications Satellite
    NFPA    National Fire Protection Association
    NFS     Nozzle Flow Sensor
    NFSP    Nonflight Switch Panel
    NFW     Nonfuel Wasting
    NG      Narrow Gage
    NG      Nitrogen Gage
    NG      Nose Gear
    NGM     Nitrogen Generation Module
    NGT     NASA Ground Terminal
    NH      Nominal Height (Adjust Maneuver)
    NH      Nominal Height Adjustment Maneuver
    NH3     Ammonia
    NH4     Hydrazine
    NHA     Next Higher Assembly
    NHB     NASA Handbook
    NHC     National Hurricane Center
    Ni      Nickel
    NI-SIL  Nickel-Silver
    NIA     NOVA Interface Adapter
    NIAT    NASA Integrated Action Team
    NIB     Noninterference Basis
    NIC     Not in Contract
    NICD    Nickel Cadmium
    NIDS    Network Interface Data System
    NIL     No Limit (NL preferred)
    NIM     Nuclear Instrumentation Module
    NIP     Network Input Processor
    NIP     Network Interface Processor
    NIP     Nipple
    NISN	NASA Integrated Services Network
    NJP     Network Job Processing
    NL      No Limit
    NLA     Next Lower Assembly
    NLG     Nose Landing Gear
    NLT     Not Later Than
    NLT     Not Less Than
    NM      Nautical Miles
    NM      Network Manager (GSFC)
    NM      Nonmetallic
    nm      Nanometer
    NMA	National Management Association
    NMAB    National Materials Advisory Board
    NMC     National Meteorological Center
    NMI     NASA Management Instruction
    NMI     Nautical Miles
    NMO     Normal Manual Operation
    NMR     Nuclear Magnetic Resonance
    NMT     Not More Than
    NMT     Notification of Master Tool
    NMV     Nitrogen Manual Valve
    NNI-I   NASA Standard Initiator-Type I (was SMSI)
    NO      Nitric Oxide
    NO      Normally Open
    NO      Not for Off-KSC Distribution
    No.     Number
    NO2     Nitrogen Dioxide
    NOAA    National Oceanic and Atmospheric Administration
    NOC     Notation of Content
    NOC     Network Operation Control
    NOC     Not Otherwise Coded
    NOCC    Network Operations Control Center
    NOCR    Network Operations Control Room
    NOES    National Operational Environmental Satellite Serv.
    NOM     Network Output Multiplexer
    NOM     Nominal
    NOR     Normal
    NOR     Northrup Flight Strip, NM (Deorb OPT site)
    NORAD   North American Air Defense Command
    NORDSAT Scandinavian Countries Broadcast Satellite
    NORM    Normal
    NOSL    Night/Day Optical Survey of Thunderstorm Lightning
    NOSP    Network Operations Support Plan
    NOSS    National Oceanic Survey Satellite
    NOZ     Nozzle
    NP      Neptunium
    NP      Network Program
    NP      Not Provided
    NPC     NASA Publication Control
    NPC     Nitrogen Purge Control
    NPC     Normal Plane Change Maneuver
    NPD     NASA Policy Directive
    NPD     Nominal Percent Defective
    NPDS    Nuclear Particle Detection Subsystem
    NPL     Normal Power Level (see RPL)
    NPLD    NASA Payloads Logistics Depot
    NPN     NASA Part Number
    NPRV    Nitrogen Pressure Relief Valve
    NPS     NASA Planning Studies
    NPSH    Net Positive Suction Head
    NPSP    Net Positive Static Pressure
    NPSP    Net Positive Suction Pressure
    NPU     Nitrogen Purge Unit
    NPV     Nitrogen Pressure  Valve
    NR      Noise Rating
    NR      Nose Right
    NR      Not Required
    NR/T    Near Real-Time
    NRC     National Research Council
    NRC     Nonrecurring Costs
    NRCC    National Research Council of Canada
    NRI     Nonrecurring Investment
    NRL     Naval Research Laboratory
    NRM     Nonrecurring Maintenance
    NRO     National Reconnaissance Office
    NRP     Normal Rated Power
    NRS     Nonconformance Reporting System
    NRT     Near Real-Time
    NRTS    Not Repairable at This Station
    NRZ     Non-Return-to-Zero
    NRZ-L   Non-Return-to-Zero Level
    NS      Nickel Steel
    NS      Not Switchable
    NS      Nuclear Shuttle
    NSA     National Standards Association
    NSD     NASA standard detonator
    NSGT    NASA Ground Terminal
    NSI-I   NASA Standard Initiator-Type I (was SMSI)
    NSLD    NASA Shuttle Logistics Depot
    NSN     National Stock Number
    NSO     NASA Support Operation
    NSP     NASA Support Plan
    NSP     Network Signal Processor
    NSR     Nominal Slow Rate
    NSR     Normal Slow Rate (Maneuver)
    NSR     National Slow Rate
    NSR1    First Coelliptic Maneuver
    NSR2    Second Coelliptic Maneuver
    NSS     Nitrogen Supply Subsystem
    NSSDC   National Space Science Data Center
    NSTL    National Space Technology Laboratory (was MTF)
    NSTL    National Space Technology Laboratories
    NSW     NSP Status Word
    nt      Newton
    NTD     NASA Test Director
    NTIS    National Technical Information Service
    NTO     Nitrogen Tetroxide
    NTP     Network Test Panel
    NTP     Normal Temperature and Pressure
    NTP     Notice To Proceed
    NTR     Nuclear Thermal Rocket
    NTS     Not to Scale
    NTS     Near Term Schedule
    NTSO    NASA Test Support Office
    NTTF    Network Test and Training Facility
    NUL     Non-GSE Utilization List
    NVAFB   North Vandenberg Air Force Base
    NVB     Navigational Base
    NVPOWG  NASA/VAFB Payload Operations Working Group
    NVR     No Voltage Release
    NVR     Nonverification Required
    NVR     Nonvolatile Residue
    NW      NASA Waiver
    NW      Nose Wheel
    NWS     National Weather Service
    NWS     Nose Wheel Steering
    NWSA    Nose Wheel Steering Amplifier
    NWSI    New World Services Inc.
    NWT     Nonwatertight
    NWW     Nose Wheel Well
    NX      Normal to X-Axis
    NX      Nose to X-Axis
    NY      Normal to Y-Axis
    NY      Nose to Y-Axis
    NZ      Normal Acceleration
    NZ      Normal Load Factor (g)
    NZ      Normal to Z-Axis
    NZ      Nose to Z-Axis
    NZB     Non Zero Binary
    
    O
    
    O       Omicron
    O       Out
    O2      Oxygen
    O&C     Operation and Checkout
    O&C     Operation(s) and Checkout (Building--was MSOB)
    O&C     Operations and Control
    O&FS    Operations and Flight Support
    O&IA    Operations and Integration Agreement
    O&M     Operation and Maintenance
    O&P     Operations and Procedures
    O&R     Overhaul and Repair
    O-NAV   Onboard Navigation
    O/B     Onboard
    O/B     Operational Base
    O/C     Operations Critical
    O/D     On Dock
    O/D     Outside Diameter
    O/E     Output Electronics
    O/ET    Orbiter/External Tank
    O/F     Oxidizet-to-Fuel Ratio
    O/L     Overload
    O/L-RC  Overload-Reverse Current
    O/O     On Orbit
    O/R     Outside Radius
    O/R     Oxygen Relief
    O/V     Overvoltage
    O/V-U/V Over Voltage/Under Voltage
    OA      Office of Applications (now OSTA)
    OA      Operational Aft (DSC or MOM)
    OA      Operational Instrumentation MDM-Aft
    OA      Orbital Assembly
    OA      Output Axis
    OA      Overall
    OAA     Orbiter Access Arm
    OAA     Orbiter Alternate Airfield
    OAA     Orbiter access arm
    OAET    Office of Aeronautics, Exploration, and Technology
    OAFD    Orbiter Air Flight Deck
    OAFTO   Orbiter Atmospheric Flight Test Office
    OAL     Overall Level
    OALC    Ogden Air Logistics Center
    OAMS    Orbital Attitude and Maneuvering System
    OANS    Orbiter Ancillary
    OAO     Orbiting Astronomical Observatory
    OART    Office of Advanced Research and Technology
    OAS     Office Automation System
    OAS     Orbiter Aeroflight Simulator
    OAS     Orbiter Atmospheric Simulator
    OAS     Orbiter Avionics System
    OASCB   Orbiter Avionics Software Control Board
    OASIS   Oceanic and Atmospheric Scientific Information System
    OASPL   Overall Sound Pressure Level
    OAST    Office of Aeronautics and Space Technology (now OAET)
    OAT     Operational Acceptance Test
    OAT     Overall Test
    OB      Onboard
    OB      Operational Base
    OB      Optical Bench
    OB      Outboard
    OBC     Onboard Computer
    OBCO    Onboard Checkout (Instrumentation)
    OBCS    Onboard Checkout Subsystem
    OBS     Observe, Observer
    OBS     Operational Bioinstrumentation System
    OBS     Operational Biomed Sensors
    OBS     Operational Biomedical System
    OBSS    Orbiter Boom Sensor System
    OBV     Oxidizer Bleed Valve
    OC      On Center
    OC      On-Condition
    OC      Open Circuit
    OC      Operations Controller
    OC      Operations Coordinator
    OC      Orbital Check
    OC      Overcurrent
    OCALC   Oklahoma City Air Logistics Center
    OCC     Office of Contract Compliance
    OCC     Operations Control Center
    OCD     Operational Capability Development
    OCDR    Orbiter Critical Design Review
    OCDU    Optics Coupling Data Unit (G&N)
    OCE     Ocean Color Experiment
    OCE     Optical Control Electronics
    OCF     Onboard Computational Facility
    OCF     Orbiter Computational Facilities
    OCGF    Organic Crystal Growth Laboratory Facility
    OCH     Orbiter Common Hardware
    OCM     Organic Content Monitor
    OCN     Order Control Number
    OCO     OMS Cutoff
    OCO     Open-Close-Open
    OCP     Output Control Pulse
    OCR     Optical Character Recognition
    OCRM    Orbiter Crash and Rescue Manuals
    OCS     Onboard Checkout System
    OCS     Optical Control System
    OCT     Octal, Octave
    OD      Operations Directive
    OD      Operational Downlink/Downlist
    OD      Outside Diameter
    OD      Oxygen Drain
    ODB     Operational Data Book
    ODC     Other Direct Costs
    ODCDR   Orbiter Delta CDR
    ODDS    Operational Data Delivery Services
    ODES    Optical Discrimination Evaluation Study
    ODF     Orbit Determination Facility
    ODIN    Orbital Design Integration (System)
    ODIN    Outsourcing Desktop Initiative for NASA/KSC
    ODP     Operational Display Procedure
    ODR     Output Data Redundancy
    ODRAN   Operational Drawing Revision Advance Notice
    ODS     Orbiter Docking System
    ODU     Output Display Unit
    OEAS    Orbital Emergency Arresting System
    OECO    Outboard Engine Cutoff
    OEM     Original Equipment Manufacturer
    OES     Orbiter Emergency Site
    OESS    Orbiter/ET Separation Subsystem
    OEX     Orbiter Experiments
    OF      Operational FWD DSC or MDM
    OF      Operational Instrumentation MDM-FWD
    OF      Orbital Flight
    OF      Outside Face
    OF      Oxidizer-to-Fuel Ratio
    OF      Oxygen Fill
    OFCC    Office of Federal Contract Compliance
    OFD     Organizational Focus Day
    OFDS    Orbiter Flight Dynamics Simulator
    OFDS    Oxygen Fluid Distribution System
    OFI     Operational Flight Instrumentation
    OFI     Opportunity for Improvement
    OFK     Official Flight Kit
    OFK     Optical Flight Kit
    OFM     Original Equipment Manufacturer
    OFP     Operational Flight Profile
    OFP     Operational Flight Program
    OFP     Orbiter Flight Program
    OFS     Orbital (Orbiter) Flight System
    OFS     Orbiter Functional Simulator
    OFT     Orbital Flight Test
    OFTDS   Orbital Flight Test Data System
    OFTM    On-Orbit Flight Technique Meeting
    OFTR    Orbital Flight Test Requirement
    OG      Outer Gimbal (Roll)
    OG      Oxygen Gage
    OG      Zero Gravity
    OGA     Outer Gimbal Angle
    OGA     Outer Gimbal Axis
    OGE     Operating Ground Equipment
    OGMT    Orbiter Greenwich Mean Time
    OGS     Outer Glideslope
    OGS     Oxygen Generation System
    OGV     Oxygen Gage Valve
    OH      Overhaul
    OH      Overhead
    OHA     Operational Hazard Analysis
    OHA     Orbital Height Adjustment Maneuver
    OHC     Onboard Hard Copier
    OHC     Optics Hand Controller
    OHF     Occupational Health Facility
    OHGVT   Orbiter Horizontal Ground Vibration Test
    OHMM    Ohmmeter
    OHP     Agency Occupational Health Program (Principal) (http://ohp.ksc.nasa.gov/)
    OI      Operational Instrumentation
    OI	Operations Interface
    OI	Orbiter Insertion
    OI	Orbiter Instrumentation
    OIA     Orbiter Interface Adapter
    OIA     Office of International Affairs
    OIB     Orbiter Interface Box
    OIC     Orbiter (Orbital) Integrated Checkout
    OIL     Operations Integration Instruction
    OIR     Operations Integration Review
    OIS     Operational Intercommunication System
    OIS     Orbiter Insertion Stage
    OIS     Orbiter Instrumentation Systems
    OISR    Open Item Status Report
    OISSP   Office of Interim Space Station Program
    OIT     Orbiter Integrated Test
    OIV     Oxidizer Isolation Valve
    OIVS    Orbiter Interface Verification Set
    OJT     On-the-Job Training
    OL      Open Loop
    OL      Operational Left DSC or MDM
    OL      Overlay
    OL      Overload
    OLDB    On-Line Data Bank
    OLF     Orbiter Landing Facility (now SLF)
    OLF     Orbiter Lifting Frame
    OLIF    Orbiter Landing Instrumentation Facilities
    OLOW    Orbiter Lift-Off Weight
    OLSA    Orbiter/LPS Signal Adapter
    OLSP    Orbiter Logistics Support Plan
    OM      Operational Mid DSC or MDM
    OM      Optical Master
    OM      Outer Marker (ILS)
    OMA     Operations Maintenance Area
    OMA     Operations Management Application
    OMA     Orbiter Maintenance Area
    OMB     Office of Management and Budget
    OMBUU   Orbiter Midbody Umbilical Unit
    OMC     Operations Management Center
    OMC     Orbiter Maintenance and Checkout
    OMCF    Operations and Maintenance Control File
    OMCF    Orbiter Maintenance and Checkout Facility
    OMD     Operations and Maintenance Documentation
    OMD     Orbiter Mating Device
    OMDP    Orbiter Maintenance Depot
    OMDP    Orbiter Maintenance Down Period
    OMD P&P Operations Maintenance Documentation Planning and Production
    OMDR    Operations and Maintenance Data Record
    OMDR1   Operations and Maintainability Data Record
    OME     Orbital Main Engine
    OME     Orbital Maneuvering Engine
    OME     Orbiter Main Engine
    OMET    Orbiter Mission Elapsed Time
    OMEWG   Orbiter Maintenance Engineering Working Group
    OMI     Operations and Maintenance Instruction
    OMIS    Operational Management Information System
    OMISS   Operation and Maintenance Instruction Summary Sheet(s)
    OML     Orbiter Mold Line
    OML     Outer Mold Line
    OML     Outside Mold Line
    OMM	Orbiter Major Modification
    OMMH    Orbiter Maintenance Man-Hours
    OMNI    Omni-Range
    OMNI    Omnidirectional
    OMP     Operations and Maintenance Plan
    OMPR    Operational Maintainability Problem Reporting
    OMPT    Observed Mass Point Trajectory
    OMR     Orbiter Management Review
    OMR     Operations Management Room
    OMR     Operations and Maintenance Requirements
    OMRB    Operating Material Review Board
    OMRC    Operational Maintenance Requirements Catalog
    OMRF    Orbiter Modification and Refurbishment Facility
    OMRP    Operations and Maintenance Requirements Plan
    OMRS    Operations and Maintenance Requirements Specification
    OMRSD   O&M Requirements and Specification Documentation
    OMRSD   Operational Maintainability Reporting Systems Document
    OMRSD   Operations and Maintenance Requirements and Specifications Document
    OMS     Operations Management System
    OMS     Orbital Maneuvering System (Subsystem)
    OMSF    Office of Manned Space Flight (now OSTS)
    OMSP    Operational Maintenance Support Plan
    OMU     Optical Measuring Unit
    OMV     Orbital Maneuvering Vehicle
    OMV     Oxygen Manual Valve
    ONBD    Onboard
    ONBT    Orbiter Neutral Buoyancy Trainer
    OND     Operator Need Date
    ONR     Office of Naval Research
    OOD     Orbiter On-Dock
    OODP    Out-of-Detent Pitch
    OODR    Out-of-Detent Roll
    OOMM    Organizational Operations and Maintenance Manual
    OOP     Out of Position
    OOS     On-Orbit Station
    OOS     Orbit-to-Orbit Shuttle
    OOS     Orbit-to-Orbit Stage
    OOSDP   On-Orbit Station Distribution Panel
    OOT     Out of Tolerance
    OP      Open
    OP      Operate
    OP      Operation
    OP      Oxygen Purge
    OPA     Operations Planning Analysis
    OPB     Oxidizer Preburner
    OPBOV   Oxidizer Preburner Oxidizer Valve
    OPDAR   Optical Detection and Ranging
    OPE     Other Project Element
    OPER    Operation
    OPER    Operations, Operate, Operator
    OPF     Orbiter Processing Facility
    OPFC    Orbiter Preflight Checklist
    OPGUID  Optimum Guidance (Technique)
    OPI     Orbiter Payload Interrogator
    OPIDF   Operational Planning Identification File
    OPIS    Orbiter Prime Item Specification
    OPL     Open Problem List
    OPL     Operational
    OPLF    Orbiter Processing and Landing Facility
    OPNS    Operational Phase
    OPO     Orbiter Project(s) Office
    OPOV    Oxidizer Preburner Oxidizer Valve
    OPP     Opportunity
    OPP     Opposite
    OPPAR   Orbiter Project(s) Parts Authorization Request
    OPPL    Orbiter Project Parts List
    OPR     Office of Primary Responsibility
    OPR     Operations Planning Review
    OPR     Operator
    OPR     Orbiter/Payload Recorder
    OPR     Oxygen Pressure Regulator
    OPRV    Oxygen Pressure Relief Valve
    OPS     Operational Sequence
    OPS     Operations
    OPS     Operations Sequence
    OPS     Orbiter Project Schedules
    OPS     Oxygen Purge System
    OPSB    Orbiter Processing Support Building
    OPSR    Operations Supervisor (GSTDN Site)
    OPSS    Orbital Propellant Storage Subsystem
    OPT     Operational Pressure Transducer
    OPT     Optics
    OPT     Optimum
    OPT     Option
    OPTB    Operational Program Time Base
    OPTB    Opposite
    OR      Operational Right
    OR      Operations Requirement
    OR      Operations Review
    OR      Operations Room
    OR      Outer Roll
    OR      Oxygen Relief
    ORB     Orbit, Orbital, Orbiter
    ORB     Order
    ORB 1-g Orbiter one-g (trainer)
    ORCHIS  Oak Ridge Computerized Hierarchical Information System
    ORD     Operational Readiness Date
    ORD     Operational Ready Data
    ORD     Operational Requirements Document
    ORD     Orbital Requirements Document
    ORD     Ordnance
    ORDC    Orbiter Data Reduction Center
    ORE     On-Orbit Repair Experiment
    ORF     Orifice
    ORG     Organization
    ORI     Operational Readiness Inspection
    ORIDE   Override
    ORIEN   Orientation
    ORIG    Origin
    ORLA    Optimum Repair Level Analysis
    ORMR    Orbiter Rollout Milestone Review
    ORP     OFS Retransmission Processor
    ORR     Operational Readiness Review
    ORR     Operations Requirements Review
    ORS     Orbital Refueling System
    ORS     Orroval Valley, Australia (STDN)
    ORSDI   Oak Ridge Selective Dissemination of Information
    ORT     Orbit Readiness Test
    ORT     Operational Readiness Test
    ORTHOG  Orthogonal
    ORU     Orbital Replacement Unit
    OS      On-Orbit Station
    OS      Operating Software
    OS      Operating System
    OS      Optics Subsystem
    OS      Orbital Servicing
    OS      Orbiter CEI Specification
    OSA     Operational Support Area
    OSC     Operations Support Center
    OSC     Orbital Sciences Corporation
    OSC     Oscillator
    OSCRS   Orbital Spacecraft Consumables Resupply System
    OSDH    Orbiter System Definition Handbook
    OSE     Orbital Support Equipment
    OSE     Orbiter Support Equipment
    OSE     Operating Support Equipment
    OSF     Office of Space Flight (now OSTS)
    OSF     Ordnance Storage Facility
    OSHA    Occupational Safety and Health Act (Activity)
    OSHA    Occupational Safety and Health Administration
    OSLM    Operations Shop/Lab Manager
    OSM     Orbital Service Module
    OSMP    Operational Support Maintenance Plan
    OSO     Ocean Systems Operation
    OSO     Orbiting Solar Observatory
    OSOP    Orbiter Systems Operating Procedures
    OSP     Operations Support Plan
    OSR     Operations Support Room
    OSS     OEX Support System
    OSS     Office of Space Science
    OSS     Office of Space Station
    OSS     Optics Subsystems
    OSS     Orbiting Space Station
    OSSA    Office of Space Science and Applications
    OSSRH   Orbiter Subsystem(s) Requirements Handbook
    OST     Operations Support Team (GSFC)
    OST     Orbiter Support Trolley
    OSTA    Office of Space and Terrestrial Application(s)
    OSTDS   Office of Space Tracking and Data Systems
    OSTO    Office of Space Transportation Operations
    OSTP    Orbiting System Test Plan
    OSTS    Office of Space Transportation Systems
    OT      Operating Time
    OT      Operational Instrumentation MDM-Tank
    OT      Operational Test
    OT      Operational Trajectory
    OT      Optical Tracker
    OT      Out Temperature
    OT      Overtime
    OT&E    Operational Test and Evaluation
    OTA     Optical Telescope Assembly
    OTB     Orbiting Tanker Base
    OTBD    Outboard
    OTC     Orbiter Test Conductor
    OTD     Operational Technical Documentation
    OTD     Orbiter Test Director
    OTDA    Office of Tracking and Data Acquisition (now OSTDS)
    OTEMP   Overtemperature
    OTH     Over-the-Horizon (Radar)
    OTK     Oxidizer Tank
    OTL     Ordnance Test Laboratory
    OTLC    Orbiter Timeline Constraints
    OTO     One-Time-Only
    OTOS    Orbit-to-Orbit Stage
    OTP     Operational Test Procedure
    OTP     Operations Test Plan
    OTP     Operations Turnaround Plan
    OTR     Operating Time Record
    OTR     Outer
    OTS     Off-the-Shelf
    OTS     Orbiter Test Conductor
    OTT     Optional Team Targeting
    OTV     Operational Television
    OTV     Orbiter Transfer Vehicle
    OUP     OFS Uplink Processor
    OUT     Orbiter Utilities Tray
    OUT     Outlet
    OUT     Output
    OUTBD   Outboard
    OV      Orbiter Vehicle
    OV      Oxygen Vent
    OVBD    Overboard
    OVCO    Operational Voice Communication Office
    OVF     Overfill
    OVFL    Overflow
    OVHD    Overhead
    OVHT    Overheat
    OVI     Operational Validation Inspection
    OVLD    Overload
    OVRD    Override
    OVS     Operational Voice System
    OVV     Overvoltage
    OW      Optical Window
    OWD     One-Way Doppler
    OWDE    One-Way Doppler Extraction
    OWF     Optimum Working Frequency
    OX      Oxidizer
    OXD     Oxide, Oxidizer
    OXDZR   Oxidizer
    OXID    Oxidizer
    OXY     Oxygen
    OZ      Ozone
    oz      Ounce
    
    P
    
    P       Pallet (Spacelab)
    P       Period
    P       Pilot
    P       Pitch
    P       Pole
    P       Pressure
    P       Primary
    P       Prime
    P       Roll Rate (Angular Rate)
    P&FS    Particles and Fields Subsatellite
    P&I     Performance and Interface (Specification)
    P&M     Performance Monitor
    P&M     Phase Modulation (Modulated)
    P&M     Planetary Mission
    P&M     Preventive Maintenance
    P&M     Processes and Materials
    P&M     Program Milestone
    P&M     Pulse Modulation
    P&R     Performance and Resources
    P&SM    Procurement and Subcontract Management
    P&W     Pratt and Whitney
    P-BAND  225 to 390 MCS
    P-P     Peak-to-Peak (Value)
    P-TUBE  Pneumatic Tube
    P-WEAR  Preliminary Work Breakdown Structure Element Audit Review
    P/A     Problem Analysis
    P/B     Pushbutton
    P/B     Preburner
    P/C     Pitch Control
    P/L     Parts List
    P/L     Payload
    P/L     Postlanding
    P/L     Purchased Labor
    P/N     Part Number
    P/P     Patch Panel
    P/P     Printer/Plotter
    P/PL    Primary Payload
    P/S     Payload Specialist
    P/S     Parallel to Serial Converters
    P/Y     Pitch/Yaw
    P1      Port 1
    PA      Pad Abort
    PA      Paging and Area Warning
    PA      Power Amplifier
    PA      Product Assurance
    PA      Public Address
    PA      Public Affairs
    PA      Pulse Amplifier
    PAC     Pressure Alpha Center
    PAC     Probe Aerodynamic Center
    PAC     Problem Action Center
    PACAS   Personnel Access Control Accountability System
    PACC    Problem Action Control Center
    PACE    Prelaunch Automatic Checkout Equipment
    PACS    Pointing and Attitude Control System
    PAD     Preliminary Advisory Data (Crew Data Uplink)
    PAD     Program Approval Document
    PAD     Propellant Acquisition Device
    PAE     Preventive Action Engineer
    PAE     Problem Assessment Engineer
    PAF     Payload Attach Fitting
    PAF     Peak Annual Funding
    PAFB    Patrick Air Force Base
    PAH     Payload Accommodations Handbook
    PALAPA  Indonesian Communications Satellite
    PALS    Photo Area and Location System
    PALS    Precision Approach and Landing System
    PAM     Payload Assist Module
    PAM     Pulse Amplifier Modulation
    PAM     Pulse Amplitude Modulation
    PAM-A   PAM, Atlas-Centaur Class Spacecraft
    PAM-D   PAM, Delta Class Spacecraft
    PAMB    Pressure Ambient
    PAO     Public Affairs Office (Officer)
    PAP     Product Assurance Plan
    PAPI    Precision Approach Path Indicator
    PAR     Planning Action Request
    PAR     Precision Approach Radar
    PAR     Problem Accountability Record
    PAR     Problem Action Record
    PAR     Problem Action Request
    PAR     Product Acceptance Review
    PARA    Paragraph
    PARAM   Parameter
    PARS    Property Accountability Record System
    PAS     Payload Accommodation Studies
    PAS     Primary Ascent System
    PASS    Planning and Scheduling System
    PASS    Primary Avionics Software System
    PAT     Problem Action Team
    PAT     Production Acceptance Test
    PATP    Preliminary Authority To Proceed
    PATS    Program for Analysis of Time Series
    PAU     Probe Aerodynamic Upper
    PAV	Pneumatic Actuated Valve
    PAV     Pressure Actuated Valve
    PAX     Passengers
    PAYCOM  Payload Command
    PAYCOM	Payload Command Controller
    PAYDAT  Payload Data
    PB      Phonetically Balanced
    PB      Playback
    PB      Preburner (P/B preferred)
    PB      Pushbutton
    PBAN    Polybutadiene Acrylonitrile (Propellant)
    PBD     Payload Bay Door
    PBDF    Payload Bay Door FWD
    PBDM    Payload Bay Door Mechanism
    PBI     Push Button Indicator
    PBIC    Programmable Buffer Interface Card
    PBIM    Programmable Buffer Interface Module
    PBK     Payload Bay Kit
    PBL     Payload Bay Liner
    PBM	Power Balance Model
    PBM     Program Business Management
    PBMA    Process-Based Mission Assurance
    PBP	Preburner Pump
    PBPS    Post-Boost Propulsion System(s)
    PBS     Protective Breathing System
    PBW     Proportional Band Width
    PC      Personal Computer
    PC      Pitch Control
    PC      Plane Change
    PC      Planetary Camera
    PC      Power Converter
    PC      Pressure Chamber
    PC      Printed Circuit (Card)
    PC      Project Control
    PC      Pulsating Current
    PCA     Payload Clamp Assembly
    PCA     Physical Configuration Audit
    PCA     Pitch Control Assembly
    PCA     Pneumatic Control Assembly
    PCA     Point of Closest Approach
    PCA     Power Control Assembly
    PCA	Primer Carrier Assembly
    PCA	Primer Chamber Assembly
    PCA	Pyrotechnic Carrier Assembly
    PCASS   Program Compliance Assurance and Status System
    PCB     Power Circuit Breaker
    PCB     Power Control Box
    PCB     Printed Circuit Board
    PCB     Product Configuration Baseline
    PCC     Pad Control Center
    PCC     Payload Control and Checkout
    PCC     Production Control Centers
    PCCB    Program Configuration Control Board
    PCCE    Payload Common Communication Equipment
    PCCM    Program Change Control Management
    PCCN    Provisioning Contract Control Number
    PCCP    Preliminary Contract Change Proposal
    PCD     Procurement Control Document
    PCDU    Payload Command Decoder Unit
    PCEM    Propulsion Contamination Effects Module
    PCF     Payload Control Facility
    PCG     Phonocardiogram
    PCG	Protein Crystal Growth
    PCG2	Personal Computer Government Operator Aerospace Language 2 
    PCGE	Protein Crystal Growth Experiment
    PCGOAL	Personal Computer Government Operator Aerospace Language
    PCH	Program Critical Hardware
    PCI     Peripheral Controller Interface
    PCI     Procedure Change Unit
    PCI     Production Configuration Identification
    PCI     Program Control Input
    PCIL    Pilot-Controlled Instrument Landing
    PCIN    Program Change Identification Number
    PCIN	Program Change Incorporation Notice
    PCIN    Program Change Integration
    PCL     Pallet Coolant Loop
    PCL     Power Control List
    PCL     Primary Coolant Line
    PCL     Primary Coolant Loop
    PCL     Programming Check List
    PCM     Power Control Mission
    PCM     Pulse Code Modulation
    PCM     Pulse Code Modulator
    PCM     Punch Card Machine
    PCME    Pulse-Code Modulation Event
    PCMD    Pulse-Code Modulation, Digital
    PCME	Pulse-Code Modulation Event
    PCMMU   PCM Master Unit
    PCMMU   Pulse-Code Modulation Master Unit
    PCMS    Pulse-Code Modulation Shared
    PCN     Page Change Notice
    PCN     Program Change Notice
    PCN     Program Control Number
    PCO     Postcheckout
    PCO     Postcheckout Operations
    PCO     Procuring Contracting Officer
    PCO     Program Controlled Output
    PCOT    Payload Center Operations Team
    PCP     Power Control Panel
    PCP     Program Change Proposal
    PCP     Project Change Proposal
    PCP     Project Cost Plan
    PCR     Payload Certification Review
    PCR     Payload Changeout Room
    PCR     Payload Checkout Room
    PCR     Power Change Request
    PCR     Program Change Request
    PCR     Project Control Room
    PCR     Publication Change Request
    PCRB    Program Change Review Board (RI Launch Operations)
    PCS     Payload Checkout System
    PCS     Payload Control Supervisor
    PCS     Pointing Control System
    PCS     Portable Computer System
    PCS     Power Conversion System
    PCS     Pressure Control System
    PCS     Primary Coolant System
    PCS     Procedure Completion Sheet
    PCT     Percent
    PCTC	Payload Crew Training Complex
    PCTE    Portable Commercial Test Equipment
    PCTO    Payload Cost Tradeoff Optimization
    PCTR    Pad Connection Terminal Room
    PCU     Payload Checkout Unit
    PCU     Power Control Unit
    PCU     Pressure Control Unit
    PCU     Process Control Unit
    PCV     Precheck Verification
    PCV     Purge Control Valve
    PCVB    Pyro Continuity Verification Box
    PCVL    Pilot Controlled Visual Landing
    PCZ     Physical Control Zone
    PD      Pitch Down
    PD      Preliminary Design
    PD      Procurement Document
    PD      Procurement Drawing
    PD      Program Directive
    PD      Project Directive
    PD      Propellant Dispersal
    PD&RS   Payload Deployment and Retrieval Subsystem
    PDA	Power Distribution Assembly
    PDA	Preliminary Design Audit
    PDA     Propellant Drain Area
    PDAR    Program Description and Requirements
    PDB     Performance Data Book
    PDB     Power Distribution Box
    PDB	Project Data Base
    PDC     Predefined Command
    PDC     Procurement Document Change
    PDCR    Proprietary Data Control Record
    PDCS    Power Distribution and Control System (Subsystem)
    PDF     Pocket Dosimeter FEMA
    PDH     Pocket Dosimeter-High
    PDI     Payload Data Interleaver
    PDIP	Program Development Integration Plan
    PDL     Pocket Dosimeter-Low
    PDL     Procedure Distribution List
    PDL     Program Design Language
    PDM     Processor Data Monitor
    PDM     Pulse Duration Modulation
    PDM/FM  Pulse Duration Modulation/Frequency Modulation
    PDMR	Program Director's Management Review
    PDMS    Payload Database Management System
    PDP     Plasma Diagnostics Package
    PDP     Postinsertion Deorbit Preparation
    PDP     Postinsertion Deorbit Prep Checklist
    PDP     Preliminary Definition Plan
    PDP     Procurement Data Package
    PDP     Program Development Plan
    PDP     Project Definition Phase
    PDR     Preliminary Data Requirements
    PDR     Preliminary Design Review
    PDR	Process Description Report
    PDR     Processed Data Recorder
    PDR	Processed Data Ring
    PDR     Program Design Review
    PDR     Program Director's Review
    PDRD    Procurement Data Requirements Document
    PDRL    Procurement Data Requirements List
    PDRM    Payload Deployment and Retrieval Mechanism
    PDRS    Payload Data and Retrieval System
    PDRS    Payload Deployment and Retrieval System(s)
    PDRSS   Payload Development and Retrieval System Simulator
    PDRSTA  Payload Deployment and Retrieval System Test Article
    PDS     Package Data System
    PDS     Partitioned Data Set
    PDS     Power Distribution System (Subsystem)
    PDS     Problem Data System
    PDSS    Payload Data System Services System
    PDU	Performance Diagnostic Unit
    PDU     Pilot Display Unit
    PDU     Power Drive Unit
    PDU     Pressure Distribution Unit
    PDU     Pulse Detection Unit
    PDV     Pressure Disconnect Valve
    PE	Perkin Elmer
    PE      Project Engineer
    PEAP    Personal Egress Air Packs
    PEB     Performance Evaluation Board
    PED	Payload Element Developer
    PED     Pedal
    PED     Pedestal
    PED	Platform Equipment Deck
    PEFO    Payload Effects Follow-on Study
    PEG     Powered Explicit Guidance
    PEHG    Payload Ethernet Hub Gateway
    PEIR    Project Equipment Inspection Record
    PEL	Precision Elastic Limit
    PEM     Plant Engineering and Maintenance
    PEN     Penicillin
    PEP     Performance Evaluation Profile
    PEP     Power Extension Package
    PER     Perigee
    PER     Period
    PER     Preliminary Engineering Report
    PERD	Payload Element Requirements Document
    PERF    Perform, Performance
    PERM    Permanent
    PERT    Program Evaluation Review Technique
    PES	Post Ejection Sequencer
    PET     Phase Elapsed Time
    PETA    Performance Evaluation and Trend Analysis
    PETB    Preflight Test Bus
    PETN    Petaerythrite Tetranitrate
    PETS    Payload Environmental Transportation System
    PETS    P/L Experiment Test System (KSC)
    PETS    POCC Experiments Timeline System (GDSD and Spacelab)
    PF      Parachute Facility
    PF      Payload Forward
    PF      Payload Function
    PF      Payload Operational Instrumentation MDM-FWD
    PF      Power Factor
    PF      Powered Flight
    PF      Preflight
    PF      Prime Function
    PF      Probability of Failure
    PF      Pulse Frequency
    PFA     Palmdale Final Assembly
    PFB     Payload Feedback
    PFB     Payload Forward Bus
    PFB     Position Feedback
    PFB     Pressure Fed Booster
    PFC     Performance Flight Certification
    PFC     Postflight Checkout
    PFC     Power Factor Corrector
    PFC	Preflight Certification
    PFC     Preliminary Flight Certification
    PFCF    Payload Flight Control Facility
    PFCS    Primary Flight Control System
    PFK     Payload Function Key
    PFL     Primary Freon Loop
    PFM     Platform
    PFM     Pulse Frequency Modulation
    PFP     Program Financial Plan
    PFP     Programmable Functional Panel
    PFR     Portable Foot Restraint
    PFRT    Preliminary Flight Rating Test
    PFRX    Preflight Relmat (X-1,2,3...9 or A,B,C...Z)
    PFS     Percent Full Scale
    PFS     Primary Flight System
    PFTA    Payload Flight Test Article
    PG      Power Generation
    PG      Pressure Gage
    PGA     Power Generating Assembly
    PGA     Pressure Garment Assembly
    PGA     Programmable Gain Amplifier
    PGC	Plant Growth (unit)
    PGC	Plant Growth Chamber
    PGCP	Particles and Gases Contamination Panel
    PGDCS   Power Generation, Distribution, and Control Subsystem
    PGE     Purge
    PGHM    Payload Ground Handling Mechanism
    PGM     Program(able)
    PGNCS   Primary G&N and Control System (Subsystem)
    PGOR    Payload Ground Operation Requirements
    PGORS   Payload Ground Operations Requirements Study
    PGOWG	Payload Ground Operations Working Group
    PGR     Spacelab Planning and Ground Rule
    PGRWG   Payload Ground Requirements Working Group
    PGS     Power Generation Subsystem
    PGSE    Payload Ground Support Equipment
    PGSM	Payload Gimbal Separation Mechanism
    PGU     Plant Growth Unit
    PGWG    Particles and Gasses Working Group
    PH      Personal Hygiene
    PH      Phase
    pH      Hydrogen-Ion Concentration (Alkalinity)
    PHA     Preliminary Hazard Analyses
    PHA     Pulse Height Analyzer
    PHARM   Predictive Health and Reliability Management
    PHCF    Pituitary Growth Hormone Cell Function
    PHF     Payload Handling Fixture
    PHF     Personal Hygiene Facility
    PHK     Personal Hygiene Kit
    PHM     Per Hundred Million
    PHMC    Probe Heater Motor Controller
    PHOTO   Photograph
    PHOTO	Photography of Mexico
    PHOTONS	Photometric Thermospheric Oxygen Nightglow Study
    PHP     Payload Handling Panel
    PHR     Payload Hazardous Report
    PHS     Payload Handling Station
    PHS&T	Packaging, Handling, Storage, and Transportation
    PHSF    Payload Hazardous Servicing Facility (KSC)
    PI      Payload Interrogator
    PI      Pen and Ink (Document Update)
    PI      Preliminary Investigation
    PI      Principal Investigator
    PI      Procurement Item
    PI      Program Introduction
    PIA     Preinstallation Acceptance
    PIA     Project Impact Analysis
    PIA	Project Initiation Agreement
    PIAR    Project Impact Analysis Report
    PIB     Pyrotechnic Installation Building
    PIC     Payload Integration Center
    PIC     Payload Integration Committee
    PIC     Preinstallation Checkout
    PIC     Programmable Interval Clock
    PIC     Pyro Ignition Control
    PIC     Pyro Initiator Capacitors
    PIC     Pyro Initiator Controller
    PIC     Pyrotechnic Initiator Controller
    PICA	Pyrotechnic Initiator Control Assembly
    PICP    Program Interface Control Plan
    PICRS   Program Information Control and Retrieval System
    PICRS   Program Information Coordination and Review Service
    PICS    Photo Index and Cataloging System
    PICS    Predefined Input Control Sequence
    PID	Parameter Identification
    PID     Payload Insertion Device
    PID     Program Information Document
    PID     Program Introduction Document
    PIDA    Payload Installation and Deployment Aid
    PIDS    Portable Image Display System
    PIE     P/L Integration Equipment
    PIECP   Preliminary Impact Engineering Change Proposal
    PIF     Payload Integration Facility
    PIGA    Pendulous Integrating Gyro Accelerometer
    PII     Procurement Instrument Identification
    PIIN    Procurement Instrument Identification Number
    PIM     Pulse Interval Modulation
    PIND    Particle Impact Noise Detection
    PIO     Payload Integration Plan
    PIO     Pilot-Induced Oscillation
    PIO     Public Information Office
    PIP     Payload Integration Plan
    PIP     Payload Interface Plan
    PIP     Plant Instrumentation Program
    PIP     Production Instrumentation Package
    PIP     Project Implementation Plan
    PIPA    Pulse Integrating Pendulum Accelerometers
    PIPA    Pulse Integrating Pendulum Assembly
    PIRN    Preliminary Interface Revision Notice
    PIT     Preinstallation Test
    PITG    Payload Integration Task Group
    PITS    Payload Integration Test Set
    PIU     Power Interface Unit
    PIU     Pyrotechnic Initiator Unit
    PIV     Peak Inverse Voltage
    PK      Peak (Valve)
    PK/PK   Peak to Peak
    PKD     Programmable Keyboard and Display
    PKG     Package
    PKM     Perigee Kick Motor
    PKT     Pocket
    PL      Payload (P/L preferred)
    PL      Plate
    PL      Plug
    PL      Postlanding (P/L preferred)
    PL      Prelaunch
    PL/SNSR Payload Sensor
    PLA     Parachute Location Aid
    PLACE   Position Location Aircraft Communications Equipment
    PLAK    PLM Late Access Kit
    PLAT    Platform
    PLB     Payload Bay
    PLB     Payload Bay
    PLBD    Payload Bay Door(s)
    PLBK    Playback (PB preferred)
    PLD     Program Listing Document
    PLDI    Payload Data Interleaver
    PLDM    Payload Management
    PLDS    Payload Support
    PLGSS   Payload Ground Support Systems
    PLH     Payload Handling
    PLI     Payload Interrogator
    PLISN   Provisioning List Item Sequence Number
    PLL     Phase Locked Loop
    PLM     Payload Management
    PLM     Payload Monitoring
    PLMS    Program Logistics Master Schedule
    PLN     Plan
    PLN     Program Logic Network
    PLRD    Payload Requirements Document
    PLRV    Payload Launch Readiness Verification
    PLS     Payload Systems
    PLS     Post Landing and Safing
    PLS     Preliminary Landing Site
    PLS     Primary Landing Site
    PLS     Propellant Loading System
    PLSL    Propellants and Life Support Laboratory
    PLSP    Payload Signal Processor
    PLSS    Portable Life Support Subsystem
    PLSS    Portable Life Support System
    PLSS    Primary Life Support Subsystem
    PLT     Pilot
    PLTS    Precision Laser Tracking System
    PLUM    Payload Umbilical Mast
    PLV     Postlanding Vent
    PLVC    Postlanding Vent Control
    PM      Payload Management
    PM      Payload Midbody
    PM      Performance Monitor
    PM      Phase modulation, phase modulated
    PM      Preventive Maintenance
    PM      Project Manager
    PM      Pulse Modulation
    PMA     Performance Monitor Annunciator
    PMA     Pressurized Mating Adapter
    PMAD    Performance Monitor Annunciation Driver
    PMAD    Power Management and Distribution
    PMAP    Performance Monitor Annunciation Panel
    PMAT    Page Map Address Table
    PMC     Payload Monitoring and Control
    PMC     Plutona-Molybdenum Cermet
    PMC     Postmanufacturing Checkout
    PMC     Private Medical Communication
    PMC     Procurement Method Code
    PMD     Palmdale (TACAN  Station)
    PMDL    Palmdale, California
    PMEL    Precision Measurements Equipment Laboratory
    PMF     Performance Monitor (Monitoring) Function
    PMF     Perigee Motor Firing
    PMF     Program Management Facility
    PMHL    Preferred Measurement Hardware List
    PMI     Preventive Maintenance Inspection
    PMI     Preventive Maintenance Instruction
    PMI     Principal Maintenance Inspector
    PMIA    Parallel Multiplexer Interface Adapter
    PMIR    Program Manager's Integration Review
    PMIS    Personnel Management Information System
    PML     Preliminary Materials List
    PMM     Property Management Manual
    PMN     Program Management Network
    PMN	Program Model Number
    PMOM    Performance Management Operations Manual
    PMON    Performance Management Operations Network
    PMP     Parts, Materials, and Processes
    PMP     Performance Management Package
    PMP     Premodulation Processor
    PMP     Program Management Plan
    PMP     Pump
    PMPL    Preferred Mechanical Parts List
    PMR     Performance Measurement Report
    PMR     Program Manager's Review
    PMS     Performance Management System
    PMS     Performance Measurement System
    PMS     Performance Monitoring System
    PMT     Planning/Management Team
    PMT     Production Monitoring Test
    PMTC    Pacific Missile Test Center
    PMU     PCM Master Unit
    PMU     Pressure Measuring Unit
    PMU     Pulse Modulation Unit
    PN      Part Number (P/N preferred)
    PN      Pseudo Noise
    PN      Pseudo-Random Noise
    PNEU    Pneumatic
    PNL     Panel
    PNP     Prenegotiation Position
    PO      Personnel Office (KSC Directorate)
    PO      Postorbit
    PO      Purchase Order
    POA     Plan of Action
    POC     Payload Operations Center
    POC     Point of Contact
    POC     Purchase Order Closeout
    POCC    Payload Operations Control Center
    POCN    Purchase Order Change Notice
    POD     Payload Operations Director
    POD     Payload Operations Division (JSC)
    POD     Probability of Detection
    POD     Proximity Opticai Device
    POE     Pilot Operational Equipment
    POGO    Pogo Suppression System
    POGO    Polar Orbiting Geophysical Observatory
    POI     Product of Inertia
    POI     Propellant Quantity Indicator
    POL     Petroleum, Oil, and Lubricants
    POLAR   Production Order Location and Reporting
    POM     Pallet-Only Mode
    POM     Printer Output Microfilm
    POMT    Planning Operations Management Team
    POP     Perpendicular-to-Orbit Plane
    POP     Polar Orbiting Platform
    POP     Preburner Oxidizer Pump
    POP     Preflight Operations Procedures
    POP     Prelaunch Operations Plan
    POP     Program Operating Plan
    POPA    Payload Ordnance Processing Area
    POPU    Push Over Pull Up
    POR     Point of Resolution
    POR     Purchase Order Request
    PORB    Production Operations Review Board
    PORCN   Production Order Records Change Notice
    PORD    Performance and Operations Requirements Document
    PORR    Preliminary Operations Requirements Review
    PORT    Portable
    POS     Pacific Ocean Ship
    POS     Portable Oxygen System
    POS     Position
    POST    Payload Operations Support Team
    POST    Positive
    POST    Program to Optimize Simulated Trajectories
    POT     Potable
    POT     Potentiometer
    POV     Peak Operating Voltage
    POV     Pneumatic Operated Valve
    POWS    Project Operating Work Statement
    PP      Partial Pressure
    PP      Planning Package
    PP      Power Pole
    PP      Program Performance
    PP      Push-Pull
    PPB     Parts per Billion (p/b preferred)
    PPB     Program Performance Baseline
    PPC     Phased Provisioning Code
    PPC     Preprocessing Center
    PPCO2   Partial Pressure CO2
    PPEP    Plasma Physics and Environmental Perturbation
    PPF     Payload Processing Facility (USAF)
    PPH     Pounds per Hour
    PPI     Plan Position Indicator
    PPI     Pulse Position Indicator
    PPIL    Priced Provisioned Item List
    PPL     Provisioning Parts List
    PPL     Priced Parts List
    PPL     Planning Parts List
    PPM     Parts per Million
    PPM     Part per Minute
    PPM     Pulse per Minute
    PPM     Pulse Position Modulation
    PPME    Pacific Plate Motion Experiment
    PPO2    Partial Pressure O2
    PPO2    Oxygen partial pressure
    PPP     Payload Patch Panel
    PPP     Peak Pulse Power
    PPP     Programmable Power Processor
    PPR     Payload Preparation Room
    PPS     Pneumatic Power Subsystem
    PPS     Printer/Plotter System
    PPS     Provisioning Performance Schedule
    PPS     Pulse Per Second
    PQGS    Propellant Quantity Gaging System
    PR      Pair
    PR      Payload Recorder
    PR      Performance Report
    PR      Position Record
    PR      Pressure
    PR      Pressure Ratio
    PR      Pressure Regulator
    PR      Primary
    PR      Problem Report
    PR      Procurement Regulation
    PR      Procurement Requisition
    PR      Pulse Rate
    PR      Purchase Request
    PRA	Probabilistic Risk Assessment
    PRAB    Program Risk Assessment Board
    PRACA   Problem Reporting and Corrective Action
    PRB     Panel Review Board
    PRB     Parachute Refurbishment Building
    PRB     Paso Robles (TACAN Station)
    PRB     Project Review Board
    PRC     People's Republic of China (Payload)
    PRC     People's Republic of China Satellite
    PRC     Planning Research Corporation
    PRCA    Problem Reporting and Corrective Action
    PRCB    Program Requirements Change Board
    PRCB    Program Requirements Control Board
    PRCB    Program Review Control Board
    PRCBD   Program Requirements Control Board Directive
    PRCBD   Program Review Control Board Directive
    PRCU    Payload Rack Checkout Unit
    PRD     Personal Radiation Dosimeter
    PRD     Procurement Regulation Directive
    PRD     Procurement Requirements Document
    PRD     Program Requirements Documents (UDS)
    PRE     Personal Rescue Enclosure
    PRE-MOD Premodulation
    PREAMP  Preamplifier
    PREF    Preference
    PREFLT  Preflight
    PREL    Preliminary
    PREP    Preparation
    PREP    Prepare
    PRES    Present
    PRESS   Pressurant
    PRESS   Pressure
    PREV    Previous
    PREVLV  Prevalve
    PRF     Parachute Refurbishment Facility
    PRF     Pulse Repetition Frequency
    PRI     Primary
    PRIM    Primary
    PRL     Page Revision Log
    PRL     Priority Rate Limiting
    PRM     Payload Retention Mechanism
    PRM     Posigrade Rocket Motor
    PRM     Pulse Rate Modulation
    PRN     Program Release Notice
    PRN     Pseudo-Random Noise
    PRN     Pulse Range Navigation
    PRO     Proceed
    PROB    Problem
    PROC    Procurement
    PROC    Procedure
    PROC    Processor, Process
    PROG    Progress
    PROG    Program
    PROJ    Project
    PROM    Programmable Read-Only Memory
    PROP    Propellant
    PROP    Proportioning
    PROP    Propulsion
    PROP    Propulsion Engineer
    PROPLT  Propellant
    PROX    Proximity
    PRP     Personnel Reliability Program
    PRPS    Programming Requirements Process Specification
    PRR     Parts Replacement Request
    PRR     Preliminary Requirements Review
    PRR     Program Requirements Review
    PRR     Pulse Repetition Rate
    PRS     Payload Retention Subsystem
    PRS     Payload Rotation Stand
    PRS     Personnel Rescue Service
    PRS     Personnel Rescue System
    PRS     Power Reactant System (Subsystem)
    PRS     Precision Ranging System
    PRS     Primary Recovery Site
    PRS     Primary Rescue Site
    PRS     Provisioning Requirements Statement
    PRSD    Power Reactant Storage and Distribution
    PRSD    Power Reactant Supply and Distribution
    PRSDS   Power Reactant Storage and Distribution System
    PRSS    Problem Report Squawk Sheet
    PRT     Pulse Repetition Time
    PRTLS   Powered Return to Launch Site
    PRV     Pressure Reduction Valve
    PS      Parachute Subsystem
    PS      Payload Specialist
    PS      Payload Station
    PS      Payload Support
    PS      Power Supply
    PS      Pressure Switch
    PS      Prime Select
    PS/FC   Power Supply/Fuel Cell
    PSA     Payload Service Area
    PSA     Payload Support Avionics
    PSA     Power Servo Amplifier
    PSA     Power Servo Assembly
    PSA     Pre/Post Sleep Activity
    PSA     Preferred Storage Area
    PSA     Pressure Switch Assembly
    PSA     Provisions Stowage Assembly
    PSAC    Presidential Scientific Advisory Committee
    PSC     Parallel Switch Control
    PSC     Program Schedule Chart
    PSCL    Propellant Systems Cleaning Laboratory
    PSCN    Preliminary Specification Change Notice
    PSD     Power Spectral Density
    PSD     Program Support Document
    PSDP    Payload Station Distribution Panel
    PSDR    Planning and Scheduling Document Record
    PSE     Payload Service Equipment
    PSE     Payload Servicing Equipment
    PSE     Payload Support Equipment
    PSE     Peculiar Support Equipment
    PSF     Payload Servicing Structure
    PSF     Point Spread Function
    PSF     Processing and Staging Facility (SRB)
    PSF     Processing and Storage Facility (ET)
    psf     Pounds Per Square Foot (lb/ft2 preferred)
    PSFC    Power Supply/Fuel Cell
    PSG     Power Subsystem Group
    PSI     Power Static Inverter
    psi     Pounds Per Square Inch (Static Pressure) (lb/in2 preferred)
    psia    Pounds Per Square Inch Absolute
    psid    Pounds Per Square Inch Differential
    PSIG    Propulsion Systems Integration Group
    psig    Pounds Per Square Inch Gauge
    psis	Pounds Per Square Inch Sealed
    PSK     Phase Shift Keyed
    PSL     Perpendicular to the Sun Line
    PSL     Pressure Seal
    PSL     Propellant Seal
    PSM     Phase Sensitive Modulator
    PSM     Propellant Storage Module
    PSM     Pyro Substitute Monitor
    PSN     Purge Sequence Number
    PSOP    Payload Systems Operating Procedures
    PSP     Payload Signal Processor
    PSP     Payload Specialist Panel
    PSP     Payload Support Plan
    PSP     Program Support Plan
    PSP     Project Schedule Plan
    PSPA    Pressure Static Probe Assembly
    PSPL    Priced Spare Parts List
    PSR     Pre-Shipment Review
    PSR     Program Status Review
    PSRD    Program Support Requirements Document
    PSS     Pad Safety Supervisor
    PSS     Payload Specialist Station
    PSS     Payload Support System
    PSS     Propellant Supply Subsystem
    PSS     Propulsion Support System
    PSSA    Payload Support Structural Assembly
    PSSP    Payload Specialist Station Panel
    PSST    Periodic Significant Scheduled Tasks
    PSSU    Patch Survey and Switching Unit
    PSTF    Payload Spin Test Facility
    PSU     Power Sensor Unit
    PSU     Power Switching Unit
    PSV     Planetary Space Vehicle
    PSW     Program Status Word
    PT      Advanced Planning and Technology Office (KSC Dir.)
    PT      Part Time
    PT      Pint
    PT      Pitch Trim
    PT      Point
    PT      Pressure Transducer
    PTA     Post-Test Analysis
    PTA     Potential Toxic Area
    PTA     Propulsion Test Article
    PTB     Payload Timing Buffer
    PTC     Passive Thermal Control
    PTC     Payload Training Complex
    PTC     Portable Temperature Controller
    PTCR    Pad Terminal Connection Room
    PTCS    Passive Thermal Control Section
    PTCS    Passive Thermal Control System
    PTCS    Payload Test and Checkout System
    PTCS    Planning, Training, and Checkout System
    PTCS    Propellant Tanking Computer System
    PTD     Provisioning Technical Documentation
    PTDDSS  PTD Data Selection Sheet
    PTF     Payload Training Facility
    PTFE    Polytetrafluorethylene
    PTI     Preliminary Test Information
    PTI     Pre-Programmed Test Input
    PTI     Programmed Test Input
    PTIS    Program Test Input System
    PTM     Pulse Time Modulation
    PTMS    Precision Torque Measuring System
    PTO     Participating Test Organizations
    PTO     Power Test Operations
    PTP     Point-to-Point Phone(s)
    PTR     Preliminary Test Report
    PTR     Printer
    PTR     Program Trouble Report
    PTS     Payload Test Set
    PTS     Payload Transportation System
    PTT     Push-to-Talk
    PTV     Pathfinder Test Vehicle
    PTVS    Portable Test and Verification System
    PU      Pickup
    PU      Power Unit
    PU      Propellant Unit
    PU      Propellant Utilization
    PUB     Publication
    PUCS    Propellant Utilization Control System
    PUGS    Propellant Utilization and Gaging System
    PUPO    Pull Up Push Over
    PUSS    Pallet Utility Support Structure
    PUV     Propellant Utilization Valve
    PV      Prevalve
    PV&D    Purge, Vent, and Drain
    PVA     Preburner Valve Actuator
    PVA     Propellant Valve Actuator
    PVD     Purge, Vent, Drain System
    PVR     Precision Voltage Reference
    PVRD    Purge, Vent, Repressurize, and Drain
    PVRO    Pyrotechnics
    PVT     Physical Vapor Transport
    PVT     Preflight Verification  Test
    PVT     Pressure, Volume, and Temperature
    PVT     Pressure/Volume/Temperature
    PVT     Private
    PVT     Pyrotechnic Verification Test
    PVTOS   Physical Vapor Transport of Organic Solids
    PVWA    Planned Value of Work Accomplished
    PVWS    Planned Value of Work Scheduled
    PW      Pulse Width
    PWA     Pratt and Whitney Aircraft
    PWA     Private Write Area
    PWA     Product Work Authorization
    PWB     Printed Wire Board
    PWBS    Program Work Breakdown Structure
    PWM     Pulse-Width Modulation
    PWMD    Printed Wiring Master Drawing
    PWR     Power
    PWS     Pricing Work Statement
    PY      Program Year
    PYRO    Pyrotechnics
    
    Q
    
    Q       Dynamic Pressure
    Q       Pitch Rate (Angular Rate)
    Q Alpha Pitch Dynamic Pressure
    Q Beta  Yaw Dynamic Pressure
    Q-BAND  36,000 to 46,000 MCS
    QA      Quality Assurance
    QAC     Quality Assurance Chart
    QACAD   Quality Assurance Corrective Action Document
    QAM     Quality Assurance Manual
    QAP     Quality Assurance Procedure
    QAR     Quality Assurance Responsible/Witness
    QATT    Qualification for Acceptance Thermal Testing
    QAVT    Qualification for Acceptance Vibration Testing
    QAVT    Qualification Acceptance Vibration Test
    QC      Quality Control
    QCB     Queue Control Block
    QCDR    Quality Control Deficiency Report
    QCOP    Quality Control Operating Procedure
    QD      Quick Disconnect
    QDR     Qualification Design Review
    QDS     Quality Data System
    QE      Quality Engineer
    QEC     Quick Engine Change
    QF      Quality Factor
    QGS     Quantity Gaging System
    QINMS   Quadruple Ion Neutral Mass Spectrometer
    QL      Quick Look
    QLDR    Quick Look Data Reference
    QLDS    Quick Look Data Station
    QLS     Quick Look Station
    QM      Qualification Motor
    QPL     Qualified Products List
    QPL     Qualified Parts List
    QPR     Quarterly Progress Report
    QPRD    Quality Planning Requirements Document
    QPS     Quality Planning Specification
    QPS     Quantity Planning Specification
    QPSK    Quadrature Phase Shift Key
    QRE     Quick-Reaction Estimate
    QRI     Quick-Reaction Integration
    QRIA    Quick-Reaction Integration Activity
    QRS     Quick-Reaction Sortie
    QRSL    Quick-Reaction Space Laboratory
    QSA     Qualification Site Approval
    QSGVT   Quarter Scale Ground Vibration Test
    QSL     Qualified Source List
    QSM     Quarter Scale Model
    QSMVT   Quarter Scale Model Vibration Testing
    QSS     Quindar Scanning System
    QT      Qualification Test
    QTP     Qualification Test Plan
    QTR     Qualification Test Report
    QTR     Quarter
    QTRS    Quarters
    QTY     Quantity
    QUAD    Quandrangle, Quadrant, Quadrature
    QUADS   Quality Achievement Data System
    QUAL    Quality
    QUAL    Qualification, Qualified
    QUAT    Quaternion
    QUI     Quito, Ecuador (STDN)
    QUIC    Quality Data Information and Control
    QUP     Quality Unit Pack
    QVT     Qualified Verification Testing
    QVVT    Qualified Verification Vibration Testing
    
    R
    
    R       Gas Constant
    R       Radius
    R       Range
    R       Range Rate
    R       Rankine
    R       Ratio
    R       Rear
    R       Receive
    R       Redundant
    R       Regulate
    R       Rehydratable
    R       Reliability
    R       Replace
    R       Resistance
    R       Right
    R       Roentgen
    R       Roll
    R       Yaw Rankine Rate
    R BAR   Radius Vector Axis
    R DOT   Range Rate to Target (+) Opening, (-) Closing
    R IMP   Minimum Range to Avoid Plum Impingement
    R&CC    Recorder and Communication Control
    R&D     Research and Development
    R&DO    Research and Development Operations (MSFC)
    R&M     Reliability and Maintainability
    R&OA    Reliability and Quality Assurance
    R&P     Reserve and Process
    R&PM    Research and Program Management
    R&R     Remove and Replace
    R&R     Rendezvous and Recovery
    R&R     Resupply and Return
    R&Z     Range and Zero
    R-T     Resistance Test
    R/A     Radar Altimeter
    R/C     Radio Command
    R/C     Rate of Climb
    R/C     Remote Control
    R/D     Rate of Descent
    R/E     Reentry
    R/I     Receiving Inspection
    R/L     Rate/Limited
    R/L     Remote/Local
    R/O     Rollout
    R/S     Range Safety
    R/S     Redundant Set
    R/T     Real Time
    R/T     Receiver/Transmitter
    R/W     Read/Write
    R/W     Runway
    RA      Radar Altimeter (R/A preferred)
    RA      Range Area
    RA      Right Aft
    RA      Right Ascension
    Ra      Radium
    RAAB    Remote Amplifier and Adaption Box
    RAAB    Remote Application and Advisory Box
    RAB     Risk Assessment Board
    RAC     Reliability Action Center
    RACS    Remote Automatic Calibration System
    RACS    Rotation Axis Coordinate System
    RACU    Remote Acquisition and Command Unit
    RAD     Radar
    RAD     Radian
    RAD     Radiation Dosage
    RAD     Radiator
    RAD     Radius
    RAD     Roentgen Absorbed Dosage
    RADAR   Radio Detecting and Ranging
    RADCC   Radiation Control Center
    RAE     Radio Astronomy Explorer
    RAF     Requirements Analysis Form
    RAG     Reusable Agenda
    RAHF    Research Animal Holding Facility
    RAI     Radar Altimeter Indicator
    RAI     Roll Attitude Indicator
    RAL     Responsibility Assignment List
    RALPH   Reduction and Acquisition of Lunar Pulse Heights
    RALT    Radar Altimeter
    RAM     Radar Absorption Material
    RAM     Random Access Memory
    RAM     Research and Applications Module
    RAM     Responsibility Assignment Matrix
    RAMA    Recap and Movement Authorization
    RANC    Radar Absorption Noise and Clutter
    RANN    Research Applied to National Needs
    RAPCON  Radar Approach and Control
    RAPS    Right AFT Propulsion System
    RAS     Requirements Allocation Sheet
    RATCC   Radar Air Traffic Control Center
    RAU     Remote Acquisition Unit
    RAUIS   Remote Acquisition Unit Interconnecting Station
    RAX     Remote Access Computing System
    RAX     Remote Access Terminal
    RB      Radar Beacon
    RBA     Radar Beacon Antenna
    RBC     Red Blood Cells
    RBC     Rotating Beam Ceilometer
    RBDE    Radar Bright Display Equipment
    RBE     Radiation Biological Effectiveness
    RBK     Right Bank
    RBL     Right Buttock Line
    RBMT    Retrospective Bibliographies on Magnetic Tape
    RBN     Radio Beacon
    RC      Range Command
    RC      Rate Command
    RC      Recovery Controller
    RC      Recurring Cost
    RC      Resistance-Capacitance
    RC      Reverse Current
    RC      Rotation Control
    RCA     Radio Corporation of America (SATCOM)
    RCA     Remote Control Amplifier
    RCAG    Remote Center Air-Ground
    RCAG    Remote Control Air-Ground
    RCB     Remote Circuit Breaker
    RCC     Range Commanders Council (DOD)
    RCC     Range Control Center
    RCC     Reinforced Carbon-Carbon
    RCC     Reusable Carbon-Carbon
    RCC     Rough Combustion Cutoff
    RCCA    Rough Combustion Cutoff Assembly
    RCCB    Remote Control Circuit Breaker
    RCCP    Recorder and Communications Control Panel
    RCD     Record
    RCDP    Record Parallel
    RCDR    Recorder
    RCHCS   Regenerable CO2 and Humidity Control System
    RCN     Requirements Change Notice
    RCP     Radiation Constraints Panel
    RCP     Right Circular Polarization
    RCP     Right Circular Polarizer
    RCPT    Receipt
    RCPT    Receptacle
    RCR     Retrofit Configuration Record
    RCS     Reaction Control System (Subsystem)
    RCSC    Reaction Control Subsystem Controller
    RCU     Remote Control Unit
    RCV     Receive
    RCVR    Receiver
    RCVS    Remote Control Video Switch (Switcher)
    RCVY    Recovery
    RCY     Remaining Cycles
    RCY     Recovery
    RD      Radiation Detection
    RD      Reference Designator
    RD      Requirements Document
    RD      Round
    RD/SB   Rudder Speed Brake
    RDA     Remote Data Access
    RDA     Resident Data Area
    RDC     Reference Designator Code
    RDC     Request for Document Change
    RDCS    Reconfiguration Data Collection System
    RDD     Requirements Definition Document
    RDF     Radio Direction Finder
    RDF     Resource Data File
    RDM     Real-Time Data Manager
    RDMTR   Radiometer
    RDOC    Reference Designation Overflow Code
    RDOUT   Readout
    RDP     Receiver and Data Processor
    RDP     Requirements Data Plan
    RDP     Requirements Development Plan
    RDR     Raw Data Recorder
    RDR     Rudder
    RDS     Rocketdyne Digital Simulator
    RDT&E   Research, Development, Test, and Evaluation
    RDTR    Radiator
    RDW     Response Data Word
    RDW     Return Data Words
    RDX     Cyclotrimethylenetrinitramine
    RDY     Ready
    RE      Responsible Engineer
    RE&T    Research Engineering and Test
    REAC    Reactant
    REACQ   Reacquisition
    REC     Receive
    REC     Record (RCD preferred)
    RECERT  Recertification
    RECHG   Recharge
    RECIP   Reciprocate
    RECOG   Recognition
    RECON   Remote Console
    RECONFIG Reconfiguration
    RECONN  Reconnaisance
    RECOV   Recovery
    RECP    Receptacle
    RECP    Request for Engineering Change Proposal
    RECRC   Recirculate
    RECS    Representative Shuttle Environmental Control System
    RECT    Rectifier, Rectify
    RECV    Receive
    RECVR   Receiver
    RED     Reduction
    REDUN   Redundancy
    REED    Rocket Exhaust Effluent Diffusion
    REEDA   Rocket Exhaust Effluent Diffusion Analysis
    REF     Reference
    REF     Refurbish, Refurbishment
    REFRIG  Refrigerate
    REFSMMAT Reference Stable Member Matrix
    REFURB  Refurbish
    REG     Register
    REG     Regulator, Regulate
    REGEN   Regenerate
    REI     Range From Entry Interface (400 K)
    REI     Runway End Identification
    REI-M   REI-Mollite
    REIL    Runway End Identification Lights
    REINF   Reinforce
    REINIT  Reinitialize
    REJ     Reject
    REL     Relative
    REL     Release
    RELMAT  Relative Matrix
    REM     Release-Engage Mechanism
    REM     Release Engine Mechanism
    REM     Release Engine Module
    REM     Release Escape Mechanism
    REM     Remove
    REM     Rocket Engine Module
    REM     Roentgen Equivalent Man
    REN RAD Rendezvous Radar
    REND    Rendezvous
    REPGROW Effects of Spatial Environment on the Reproduction and Growth of Bacteria
    REPL    Replace
    REPR    Repressurization
    REPRO   Reproduction
    REQ     Request
    REQ     Require
    REQD    Required
    REQMTS  Requirements (RQMTS preferred)
    RES     Reserve
    RES     Reservoir
    RESID   Residual
    RESIS   Resistance
    RESP    Responsibility
    RESVR   Reservoir
    RET     Retract
    RETEN   Retention
    RETRO   Retrofire
    RETRO   Retrofire Officer
    RETRO   Retro Controller (NASA)
    RETRV   Retrieve
    RETS    Reconfigurable Electrical Test Stand
    RETS    Reconfiguration Electrical Test Stand
    REV     Reverse
    REV     Review
    REV     Revision
    REV     Revolution
    RF      Communications Support
    RF      Radio Frequency
    RF      Right Forward
    RF-TK   Radio Frequency Tracking
    RFA     Request for Action
    RFA     RF Authorization (Frequency)
    RFB     Ready for Baseline
    RFB     Request for Bid
    RFC     Radio Frequency Charts
    RFC     Request for Change
    RFC     Request for Change Revolution
    RFCP    Request for Computer Program
    RFD     Requirements Formulation Document
    RFE     Request for Estimate
    RFEI    Request for Engineering Information
    RFI     Remote Facility Inquiry
    RFI     Request for Information
    RFI     Remote File Inquiry
    RFI     Radio Frequency Interference
    RFL     Reflect
    RFM     Reconfigurable Furnace Module
    RFO     Request for Order
    RFP     Request for Proposal
    RFP     Requirements and Formulation Phase
    RFPA    Request for Proposal Authorization
    RFQ     Request for Quotation
    RFT     Ready for Training
    RFW     Request for Waiver (Deviation)
    RG      Radio Guide
    RG      Rate Gyro
    RGA     Rate Gyro Assembly
    RGA     Residual Gas Analyzer
    RGAL    Rate Gyro Assembly-Left SRB
    RGAO    Rate Gyro Assembly-Orbiter
    RGAR    Rate Gyro Assembly-Right SRB
    RGM     Redundant Gyro Monitor
    RGP     Rate Gyro Package
    RGRMA   Rate Gyro Redundancy Management Algorithm
    RH      Relative Humidity
    RH      Right Hand
    RHC     Right Hand Circular
    RHC     Rotation Hand Controller
    RHCM    Relative Humidity Control/Monitor
    RHCP    Right Hand Circular Polarization (Polarized)
    RHEB    Right Hand Equipment Bay
    RHEO    Rheostat
    RHFEB   Right Hand Forward Equipment Bay
    RHL     Residual Hazards List
    RHM     Relative Humidity Monitor
    RHP     Right Hand Panel
    RHS     Right Hand Side
    RHS     Rocketdyne Hybrid Simulator
    RHSC    Right Hand Side Console
    RHT     Radiant Heat Temperature
    RHU     Radioisotope Heater Unit
    RHW     Router Header Word
    RI      Rockwell International
    RIB     Recoverable Item Breakdown
    RIB     Right Inboard
    RIC     Resistance Inductance and Capacitance
    RIC     Rockwell International Corporation
    RICC    Remote Intercomputer Communications Interface
    RID     Reaction Injection Molded
    RID     Review Item Disposition
    RIDI    Receiving Inspection Detail Instruction
    RIE     Right Inboard Elevon
    RIF     Relative Importance Factor
    RIG     Rate Integration Gyro
    RIGI    Receiving Inspection General Instruction
    RIL     Recoverable Item(s) List(s)
    RIL     Repairable Item List
    RIL     Reparable Item List
    RIM     Reaction Injection Molded
    RIMS    Retarding Ion Mass Spectrometer
    RIPS    Radar Impact Prediction System
    RIR     Reportable Item Report
    RIS     Reporting Identification Symbols
    RISA    Rapid Imaging Spectrophotometric Array
    RISKAC  Risk Acceptance
    RIT     Request for Interface Tool
    RIU     Remote Interface Unit
    RIV     Recirculation Isolation Valve
    RJ/EC   Reaction Jet/Engine Control
    RJC     Reaction Jet Control
    RJD     Reaction Jet Device
    RJD     Reaction Jet Driver
    RJDA    Reaction Jet Driver Aft
    RJDF    Reaction Jet Driver Forward
    RJEC    Reaction Jet Engine Control
    RJOD    Reaction Jet OMS Driver
    RK      Recharge
    RKD     Rocketdyne
    RL      Return Link
    RLA     Repair Level Analysis
    RLA     Repair Line Agreement
    RLC     Remote Load Controller
    RLCD    Redline Cutoff Device
    RLEO    Request Liaison Engineering Order
    RLF     Relief
    RLG     Ring Laser Gyro
    RLO     Rack Level Outgassing
    RLSS    Regenerative Life Support System
    RLT     Return Line Tether
    RLV     Reusable Launch Vehicle
    RLY     Relay
    RM      Redundancy Management
    RM      Reference Mission
    RM      Remote Manipulator
    RM      Rendezvous Maneuver
    RM      Rescue Module
    RM      Right Mid
    RM/MS&C Redundancy Management/Moding, Sequencing, and Control
    RMA     Remote Manipulator Arm
    RMC     Redundancy Management Control
    RMCD    Radiation Monitoring Container Dosimeter
    RME     Radiation Monitoring Equipment
    RMF     RCS Module Forward
    RMG     Right Main Gear
    RMI     Radio Magnetic Indicator
    RMO     Resident Manager's Office
    RMRS    Repeatable Maintenance and Recall System
    RMS     Radian Means per Second
    RMS     Random Motion Simulator
    RMS     Redundancy Management System
    RMS     Remote Manipulator System (Subsystem)
    RMS     Root-Mean-Square
    RMSVP   Remote Manipulator Subsystem Verification Plan
    RMT     Remote
    RN      Reynolds Number
    RNDZ    Rendezvous
    RNG     Range
    RNG RT  Range Rate
    RO      Radar Operator
    RO      Readout
    RO      Receive Only
    RO      Recovery Operations
    ROB     Right Outboard
    ROC     Record of Comments
    ROC     Regional Operations Center
    ROC     Request of Change
    ROD     Remote Operated Door(s)
    RODB    Remote Object Data Base
    ROLL    Roll Angle
    ROM     Read-Only Memory
    ROM     Rough Order of Magnitude
    ROPE    Research on Orbital Plasma Electrodynamics
    ROS     Regulated Oxygen Supply
    ROS     Regulated Oxygen System
    ROS     Removable Overhead Structure
    ROS     Rosman, North Carolina (STDN Site)
    ROSAT   Roentgensatellite
    ROT     Remaining Operating Time
    ROT     Rota, Spain
    ROT     Rotate, Rotation
    ROTI    Recording Optical Tracking Instrument
    ROUT    Rollout
    RP      Relative Pressure
    RP      Repair Period
    RP      Rocket Propellant
    RPA     Record and Playback Assembly
    RPA     Request for Procurement Action (Authorization)
    RPC     Remote Power Controller
    RPE     Reliability Project Engineer
    RPIE    Real Property Installed  Equipment
    RPL     Rated Power Level
    RPLC    Replace
    RPM     Rendezvous Pitch Maneuver
    RPM     Revolutions per Minute
    RPO     Radiation Protection Officer
    RPOC    Remote Payload  Operations  Center
    RPP     Reinforced Pyrolytic Plastic
    RPS     Record and Playback System (Subsystem)
    RPS     Revolutions per Second
    RPSF    Rotation, Processing and Surge Facility
    RPT     Resident Provisioning Team
    RPT     Rudder Pedal Transducer
    RPTA    Rudder Pedal Transducer Assembly
    RPV     Remotely Piloted Vehicle
    RQ      Respiratory Quotient
    RQMT    Requirement
    RQMTS   Requirements
    RR      Range Rate
    RR      Rendezvous Radar
    RR      Requirements Review
    RR      Respiration Rate
    RREA    Rendezvous Radar Electronics Assembly
    RREU    Rendezvous Radar Electronics Unit
    RRI     Rendezvous Radar Indicator
    RRL     Rudder Reference Line
    RRP     Rudder Reference Plane
    RRR     Risk Reduction Review
    RRT     Rendezvous Radar Transducer
    RRT     Rendezvous Radar Transponder
    RS      Rawinsonde
    RS      Redundancy Status
    RS      Redundant Set
    RS      Refurbishment Spare
    RS      Remote Station
    RS      Right Side
    RS&H    Reynolds, Smith, & Hills, Inc.
    RS&S    Receiving, Shipping, and Storage
    RSA     Reference Satellite A
    RSB     Rudder Speed Brake
    RSC     Range Safety Control/Command
    RSCIE   Remote Station Communication Interface Equipment
    RSD     Requirements and Specifications Document
    RSDP    Remote Site Data Processor
    RSF     Receiving-Safing Facility
    RSF     Refurbishment and Subassembly Facilities
    RSF     Refurbishment and Subassembly Facility (KSC)
    RSI     Reusable Surface Insulation
    RSL     Resource Support List
    RSLS    Redundant Set Launch Sequencer
    RSLV    Resolve
    RSM     Resume
    RSMM    Redundant System Monitor Model
    RSO     Radiological Safety Office
    RSO     Range Safety Officer
    RSP     Rendezvous Station Panel
    RSPL    Recommended Spare Parts List
    RSS     Range Safety Switch
    RSS     Range Safety System
    RSS     Reactants Supply System
    RSS     Rib Structure Station
    RSS     Robotic Servicer System
    RSS     Root Sum Square
    RSS     Rotating Service Structure
    RSSPO   Resident Space Shuttle Project Office (Officer)
    RST     Recessed Selectromatic Terminal
    RST     Requirements Synthesis Team
    RSTRT   Restart
    RSU     Remote Service Unit
    RSVR    Reservoir
    RSYS    Responsible System
    RT      Range-to-Target
    RT      Rate
    RT      Real Time (R/T preferred)
    RT      Receiver-Transmitter
    RT      Reference Trajectory
    RT      Right
    RTA     Real-Time Accumulator
    RTAC    Research and Technology Advisory Committee
    RTADS	Real-Time Attitude Determination System
    RTB     Resistance Temperature Bulb
    RTC     Real-Time Clock
    RTC     Real-Time Command
    RTC     Real-Time Computer
    RTC     Room Temperature Cure
    RTCC    Real-Time Command Controller
    RTCC    Real-Time Computer Command (Uplink)
    RTCC    Real-Time Computer Complex
    RTCC    Real-Time Computer Center (NASA)
    RTCE    Rotation/Translation Control Electronics
    RTCL    Reticle
    RTCP    Real-Time Communications Processor
    RTCS    Real-Time Computer System
    RTD     Rate Damping
    RTD     Real-Time Display
    RTD     Resistance Temperature Device
    RTE     Responsible Test Engineer
    RTF	Return to Flight
    RTG     Radioisotope Thermal Generation
    RTG     Radioisotope Thermoelectric Generator
    RTG     Range (Slant) to Ground
    RTHC    Rotation-Translation Hand Controller
    RTHS    Real-Time Hybrid System
    RTIF    Real-Time Interface
    RTLS    Return to Launch Site
    RTN     Return
    RTO     Responsible Test Organization
    RTOP    Research and Technology Objectives and Plans
    RTR	Real-Time Ring
    RTR     Rotor
    RTS     Real-Time Supply
    RTS     Remote Tracking Station
    RTSF    Real-Time Simulation Facility
    RTTV    Real-Time Television
    RTU     Remote Terminal Unit
    RTV     Room-Temperature Vulcanized
    RTV     Room-temperature vulcanizing
    RU      Remote Unit
    RUD     Rudder
    RUPT    Interrupt
    RUPT    Rupture
    RUT     Resource Utilization Time
    RV      Recirculation Valve
    RV      Recovery Vehicle
    RV      Recovery Vessel
    RV      Reentry Vehicle
    RV      Relief Valve
    RV      Retrieval Vessel
    RVCF    Remote Vehicle Checkout Facility
    RVDT    Rotary Variable Differential Transducer
    RVDT    Rotary Variable Differential Transformer
    RVN     Requirements Verification Network
    RVR     Runway Visible (or Visual) Range
    RVS     Reverse
    RW      Response Word
    RWA     Reaction Wheel Assembly
    RWD     Right Wing Down
    RWM     Read/Write Memory
    RYD     Real Year Dollars
    RZ      Return-to-Zero
    
    S
    
    (S)     Safe (Task Classification)
    S       Second
    S       Side
    S       Star
    S       Stere
    s       Second (Astronomical Tables)
    S CHG   Supercharge
    S PRES  Star Present
    S TRK   Star Tracker
    S&A     Safe and Arm (Device)
    S&A     Science and Application
    S&AD    Science and Applications Directorate
    S&E     Science and Engineering (MSFC Directorate)
    S&H     Safety and Health
    S&MA    Safety and Mission Assurance
    S-BD    S-Band
    S-Band  1,500 to 5,200 MHz
    S-MOWG  "Super" Management Operations Working Group
    S-N     Stress Number
    S/A     Safe and Arm
    S/A     Scheduled/Actual
    S/A     Site Activation
    S/A     Spacecraft Adapter
    S/A     Subassembly
    S/AC    Stabilization/Attitude Control
    S/B     Standby
    S/C     Sensor/Controller
    S/C     Signal Conditioner
    S/C     Software Contractor
    S/C     Spacecraft
    S/C     Splitter/Combiner
    S/C     Stabilization and Control
    S/C     Stripchart (Recorder)
    S/C     Subcontractor
    S/EOS   Standard Earth Observation Satellite
    S/F     Safety Factor
    S/F     Single Flow
    S/G     Strain Gage
    S/L     Shop/Laboratory
    S/M     Scheduled Maintenance
    S/M     Service/Maintenance
    S/M     Structural/Mechanical
    S/M     Systems management
    S/N     Serial Number
    S/N     Signal-to-Noise Ratio
    S/O     Shutoff
    S/O     Switchover
    S/P     Serial to Parallel
    S/P     Signal Processor
    S/R     Send and Receive
    S/R     Shift Register
    S/R     Stimulus/Response
    S/S     Samples per Second
    S/S     Single Sideband
    S/S     Space Shuttle
    S/S     Subsystem
    S/SI    Simulation and System Infrastructure
    S/Sys   Subsystem
    S/U     Set Up
    S/V     Space Vehicle
    S/V     Supply Valve
    S/W     Software
    S1      Starboard 1
    SA      Safing Area
    SA      Shaft Angle
    SA      Single Access
    SA      Site Activation
    SA      Subaccount
    SA      Supplemental Agreement
    SA      Support Area
    SA      Supportability Analysis
    SAA     South Atlantic Anomaly
    SAA     System Assurance Analysis
    SAAC    Schedule Allocation and Control
    SAALC   San Antonio Air Logistics Center
    SAAM    Special Air Force Airlift Mission
    SAAMA   San Antonio Air Material Area
    SAAS    Shuttle Aerosurface Actuator Simulation
    SAB     Shuttle Avionics Breadboard
    SAB     Spacecraft Assembly Building
    SAB     Storage and Assembly Building
    SAC     Shuttle Action Center (HOSC)
    SAC     Strategic Air Command (USAF)
    SAC     Support Action Center
    SACS    Software Avionics Command Support
    SACS    Systems Software Avionics Command Support
    SAD     Shuttle Authorized Document
    SAD     Spacecraft Attitude Display
    SAD     Systems Allocation Document
    SADA    Solar Array Drive Assembly
    SADE    Solar Array Drive Electronics
    SADE    Structural Assembly Demonstration Experiment
    SADEC   Spin Axis Declination
    SADM    Solar Array Drive Mechanism
    SAE     Society of Automotive Engineers
    SAE     Solar Array Experiment
    SAEF    Spacecraft Assembly and Encapsulation Facility
    SAES    Stand-Alone Engine Simulator
    SAFD    Systems Anomaly and Failure Detection
    SAFE    San Andreas Fault Experiment
    SAFE    Solar Array Flight Experiment
    SAGE-II Stratospheric Aerosol Gas Experiment
    SAIL    Shuttle Avionics Integration Laboratory
    SAL     Scientific Airlock
    SAL     Shuttle Avionics Laboratory
    SALC    Sacramento Air Logistics Center
    SAM     Shuttle Attachment Manipulator
    SAM     System Activation and Monitoring
    SAMP    Shuttle Automated Mass Properties
    SAMS    Shuttle Attachment Manipulator System
    SAMSO   Space and Missile Systems Organization (USAF)
    SAMSOR  SAMSO Regulation (now SDR)
    SAMTEC  Space and Missile Test Center (VAFB, CA)
    SAMTEC  Space and Missile Test Center Manual
    SAMTO   Space and Missile Test Organization (VAFB)
    SANC    Spacelab Ancillary Data Tape
    SAND    Site Activation Need Date
    SAO     Smithsonian Astrophysical Observatory
    SAP     Strain Arrestor Plate
    SAR     Safety Analysis Report
    SAR     Search and Rescue
    SARP    Safety Analysis Report for Packaging
    SARP    Shuttle Astronaut Recruitment Program
    SARR    Small and Rapid Response
    SART    Stimuli Analog Refresh Table
    SAS     Small Astronomy Satellite
    SAS     Solar Array System
    SAS     Space Adaptation Syndrome
    SAS     Stability Augmentation Subsystem
    SAS     Stability Augmented System
    SASA    S-Band Antenna Structural Assembly
    SASE    Shuttle Atmospheric Science Experiment
    SASP	Science and Applications Space Platform
    SASTP   Stand-Alone Self-Test Program
    SAT     Saturate, Saturated
    SAT     Systems Approach to Training
    SATAF   Shuttle Activation Task Force
    SATO    Shuttle Attached Teleoperator
    SATO    Supply and Transportation Operations
    SATS    Shuttle Avionics Test System
    SATS	Small Aircraft Transportation System
    SATS    Small Applications Technology Satellite
    SAU     Signal Acquisition Unit
    SAU     Strap Around Unit
    SAVER   Shuttle Avionics Verification and Evaluation
    SAWD    Solid Amine Water Desorbed
    SB      Space Base
    SB      Speed Brake
    SB      Synchronization Base
    SB      Synchronization Bit
    SBA     Seat Back Assembly
    SBA     Small Business Administration
    SBA     Structure Borne Acoustic
    SBAS    S-Band Antenna Switch
    SBC     Speed Brake Command
    SBCR    Stock Balance and Consumption Report
    SBD     Schematic Block Diagram
    SBE     Sub-Bit Encoder
    SBHC    Speed Brake Hand Controller
    SBP     San Luis Obispo (TACAN Station)
    SBP     Sonic Boom Panel
    SBS     Satellite Business System
    SBTC    Speed Brake/Thrust Controller
    SBU     Sensitive But Unclassified
    SBX     S-Band Transponder
    SC      Scale
    SC      Service Charge
    SC      Signal Conditioner (S/C preferred)
    SC      Statement of Capability
    SC      Statement of Compatibility
    SC      Support Contractor
    SC      Surface Command
    SCA     Schedule Change Authorization
    SCA     Sequence Control Assembly
    SCA     Shuttle Carrier Aircraft
    SCA     Simulation Control Area
    SCA     Sneak Circuit Analysis
    SCADA	Supervisory Control and Data Acquisition
    SCAMA   Station Conferencing and Monitoring Arrangement
    SCAN    Antenna Scan
    SCAN    Selected Current Aerospace Notices
    SCAN    Shuttle Connector Analysis Network
    SCAPE   Self-Contained Atmospheric Protective Ensemble
    SCARAB  Submersible Cable Assistant Repair and Burial
    SCARS   Serialized Control and Record System
    SCARS   Serialized Control and Reporting System
    SCARS   Sneak Circuit Analysis Report Summary
    SCAS    Subsystem Computer Application Software
    SCAT    Space Communication and Tracking
    SCAT    Storage, Checkout, and Transport
    SCATHA  Spacecraft Charging at High Altitudes
    SCATS	Simulation Control and Training System
    SCB     Schedule Change Board
    SCB     Selection Control Board
    SCB     Selector Control Box
    SCB     Software Control Board
    SCB     Specification Control Board
    SCBD    Seller's Approved Configuration Baseline Document
    SCC     Safety Control Center
    SCC     Simulation Control Center
    SCC     Slidell Computer Complex
    SCC     Standard Cubic Centimeters
    SCCB    Site Configuration Control Board
    SCCF    Solar Cell Calibration Facility
    SCCH    Standard Cubic Centimeters per Hour
    SCCM    Standard Cubic Centimeters per Minute
    SCCS    Signal Conditioning and Control System
    SCCS    Standard Cubic Centimeters per Second
    SCD     Source Control Document
    SCD     Source Control Drawing
    SCD     Specification Control Document
    SCD     Specification Control Drawing
    SCDA    Safing, Cooldown, and Decontamination Area
    SCDP    Simulation Control Data Package
    SCDR    Seller Critical Design Review
    SCDR    Shuttle Critical Design Review
    SCDR    Software Critical Design Review
    SCDR    Subcontractor Critical Design Review
    SCDU    Signal Conditioning and Display Unit
    SCE     Signal Conditioning Equipment
    SCEA    Signal Conditioning Electronics Assembly
    SCF     Safing and Deservicing Facility
    SCF     Satellite Control Facility
    SCF     Sequenced Compatibility Firing
    SCF     Spacecraft Control Facility
    SCF     Standard Charge Factor
    SCF     Standard Cubic Feet
    SCF     Statistical Collection File
    SCF     Sunnyvale Control Facility
    SCFH    Standard Cubic Feet per Hour
    SCFM    Standard Cubic Feet per Minute
    SCFS    Standard Cubic Feed per Second
    SCGSS   Super Critical Gas Storage System
    SCHE    Stowage Cargo Handling Equipment
    SCHED   Scheduled, Scheduling
    SCHEM   Schematics
    SCI     Switch Closure In
    SCIM    Standard Cubic Inches per Minute
    SCIS    Standard Cubic Inches per Second
    SCIT    Standard Change Integration and Tracking
    SCIU    Selector Control Interface Test
    SCIU    Space Interface Unit
    SCL     Secondary Coolant Line
    SCL     Secondary Coolant Loop
    SCL     Specification Change Log
    SCLM    Stability, Control, and Load Maneuvers
    SCM     Site Configuration Message
    SCM     Subsystem Configuration Management
    SCM     Subsystem Configuration Monitoring
    SCM     System Control Module
    SCMB    Development Configuration Management Board
    SCMP    System Contractor Management Plan
    SCN     Specification Change Notice
    SCNP    Preliminary Specification Change Notice
    SCNR    Scanner
    SCO     Start Checkout
    SCO     Subcarrier Oscillator
    SCO     Super Critical Oxygen
    SCO     Switch Closure Out
    SCOE    Special Checkout Equipment
    SCOPE   Science Calibration and Onboard Performance Evaluator
    SCOS    Subsystem Computer Operating System
    SCP     Scanner Control Power
    SCP     Specific Candle Power
    SCR     Schedule Change Request
    SCR     Sneak Circuit Report
    SCR     Software Change Request
    SCR     Stripchart Recorders
    SCRG    System Change Review Group (MSFC)
    SCRL    Station Configuration Requirement List
    SCRS    Serialized Control and Reporting System
    SCRS    Strip Chart Recording System (Subsystem)
    SCRSY   Serialized Control and Record System
    SCS     Secondary Coolant System
    SCS     Spacecraft Control System
    SCS     Stabilization and Control System (Subsystem)
    SCS     System Configuration Switch
    SCSI    Small Computer System Interface
    SCT     Scanning Telescope
    SCU     Secondary Control Unit
    SCU     Sequence Control Unit
    SCU     Service and Cooling Umbilical
    SCU     Signal Conditioning Unit
    SCU     Signal Control Unit
    SCU     System Control Unit
    SD      Scaling and Display
    SD      Smoke Detector
    SD      Solar Dynamic
    SD      Space Division (AFSC)
    SD      Space Division (Rockwell)
    SD      Spare Disposition
    SD      Specification Document
    SD      Subscale Demonstrator
    SD      Supplier Documentation
    SD/FS   Smoke Detector/Fire Suppression
    SD/YVV  SD/Launch Base Division
    SDA     Shaft Drive Axis
    SDA     Source Data Automation
    SDAF    Solid Rocket Booster Disassembly Facility
    SDB     Shallow Draft Barge
    SDB     Shallow Draft Board
    SDC	Shuttle Data Center
    SDC     Software Development Computer
    SDC     Spares Disposition Code
    SDCL    Supplier Documentation Checklist
    SDCP    Summary Development Cost Plan
    SDCS    SAIL Data Communications System
    SDCV    Shuttle Derived Cargo Vehicle
    SDD     Shuttle Design Directive
    SDD     Software Description Document
    SDD     Software Design Document
    SDD     System Design Document
    SDE     Space Division Evaluator
    SDF     Safing and Deservicing Facility
    SDF     Single Degree of Freedom
    SDF     Software Development Facility
    SDF     System Development Facility (Breadboard)
    SDG     Supplier Documentation Group
    SDH     Software Development Handbook
    SDH     System Definition Handbook
    SDH     System Development Handbook
    SDI     Selective Dissemination of Information
    SDIF    Software Development and Integration Facility
    SDL     Software Development Laboratory
    SDL     Standard Distribution List
    SDM     Secondary Deployment Mechanism
    SDM     Shuttle Data Management
    SDM     Subsystem Design Manuals
    SDM     System Definition Manual
    SDMU    Serial Data Management Unit
    SDN     Software Development Note
    SDP     Shuttle Data Processor
    SDP     Site Data Processor
    SDP     Software Development Plan
    SDP     Supplier Data Package
    SDPC    Shuttle Data Processing Complex
    SDPF    Sensor Data Processing Facility
    SDR     Software Design Requirements
    SDR     Software Design Review
    SDR     Space Division Regulation
    SDR     Spacelab Disposition Record (ESA)
    SDR     Subcontract Data Requirement
    SDR     System Design Review
    SDRB    Software Design Review Board
    SDRB    Supplier Documentation Review Board
    SDRB    System Design Review Board
    SDRD    Supplier Data Requirements Description
    SDRD    Supplier Documentation Review Data
    SDRL    Subcontract Data Requirements List
    SDRL    Supplier Data Requirements List
    SDS     Shuttle Dynamic Simulation (Simulator)
    SDS     Sensor Display System
    SDS     Software Design Specification
    SDS     Steering Damping System
    SDSS    Space Division Shuttle Simulator
    SDT     Scaling and Display Task
    SDT     Shuttle Data Tape
    SDT     Structural Dynamic Test
    SDTA    Structural Dynamic Test Article
    SDV     Shuttle Derived Vehicle
    SDVF    Software Development and Verification Facilities
    SE      Science and Engineering (workstation)
    SE      Student Experiment
    SE      Support Equipment
    SE      System Element
    SE      Systems Engineering
    SE&I    Systems Engineering and Integration
    SE/FAC  Support Equipment/Facility
    SEA     Scanning Electrostatic Analysis
    SEA     Sensor Electronics Assembly
    SEA     Silicon Elastimeter Ablator
    SEACF   Support Equipment Assembly and Checkout Facility
    SEADS   Shuttle Entry Air Data Sensor
    SEADS   Shuttle Entry Air Data System (Subsystem)
    SEAID   Support Equipment Abbreviated Items Description
    SEAPG   Support Equipment Acquisition Planning Group
    SEARCHS Shuttle Engineering Approach/Rollout Control Hybrid Simulation
    SEB     Scientific Equipment Bay
    SEB     Source Evaluation Board
    SEB     Support Equipment Building
    SEB     Systems Engineering Branch
    SEC     Secondary
    SEC     Sequential Events Controller
    SEC     Source Evaluation Committee
    sec     Second (s preferred)
    SECIB	Shuttle Engineering Change Implementation Board
    SECO    Sustainer Engine Cutoff
    SECS    Shuttle Events Control Subsystem
    SECT    Spacelab Experiment Channel Tape
    SEDS    Small Expendable Deployer System
    SEDT    Spacelab Experiment Data Tape
    SEE     Special Purpose End Effector
    SEE     Standard End Effector
    SEEDS   Space-Exposed Experiment Developed for Students
    SEG     Segment
    SEG     System Engineering Groundrule
    SEI     Support Equipment Installation
    SEI     System Engineering Instrumentation
    SEICO   Support Equipment Installation and Checkout
    SEII    Servoactuator Error Indication Interrupt
    SEL     Select, Selector
    SEM     Sample Exchange Mechanism
    SEM     Scanning Electron Microscope
    SEM     Seller's Engineering Memorandum
    SEM     Space Environment Monitoring
    SEM     Spacecraft Equipment Module
    SEM     System Engineering Management
    SEMA	Support Equipment Move Authorization
    SEMS    Space Environment Monitor System
    SEN     Sensor
    SEND    Shared Equipment Need Date
    SENS    Sensitivity
    SEO     Special Engineering Order
    SEO     Subtransfer Earth Orbit
    SEOS    Synchronous Earth Observation Satellite
    SEP     Separation
    SEP     Source Evaluation Panel
    SEP     Support Equipment Package
    SEP     Support Electronics Package
    SEPAC   Space Experiment with Particle Accelerators
    SEPAP   Shuttle Electrical Power Analysis Program
    SEPAR   Shuttle Electrical Power Analysis Report
    SEPS    Solar Electric Propulsion System
    SEQ     Sequence, Sequencer
    SER     Serial
    SERB    Shuttle Engineering Review Board
    SERB    Systems Engineering Review Board
    SERS    Shuttle Equipment Record System
    SERV    Service
    SERV    Single Stage Earth Orbital Reusable Vehicle
    SERVICE Space Entry Recovery Vehicle in Commercial Environments
    SERVO   Servomechanism
    SES     Senior Executive Service
    SES     Shuttle Engineering Simulation
    SES     Special Emphasis Study
    SES     Systems Engineering Simulation
    SESA    Special Equipment Stowage Facility
    SESAC   Space and Earth Sciences Advisory Committee
    SESAME  Severe Environmental Storms and Mesoscale Experiment
    SESC    Shuttle Events Sequential Control
    SESL    Space Environmental Simulation Laboratory
    SETI    Search for Extraterrestrial Intelligence
    SETS    Shuttle Electrodynamic Tether System
    SEUL    Support Equipment Utilization List
    SEWP    Scientific & Engineering Workstation Procurement
    SF      Safe
    SF      Safe, R and QA (R&QA), and Protective Services (KSC Directorate)
    SF      Safety Factor
    SF      Scale Factor
    SF      Selection Filter
    SF      Signaling Frequency
    SF      Sliding Filter
    SF      Star Field
    SF      Static Firing
    SF      Subcontractor Furnished
    SF-SOO  KSC Safety Operations Office
    SFA     Space Flight Awareness
    SFA     Sun Finder Assembly
    SFACI   Software Flight Article Configuration Inspection
    SFC     Selection Filter Control
    SFC     Specific Fuel Consumption
    SFCS    Survival Flight Control System
    SFD     Crossfeed
    SFDS    System Functional Design Specification
    SFDT    Site Format Dump Tape
    SFEX    Solar Flare X-ray Polarimeter
    SFL     Secondary Freon Loop
    SFME    Storable Fluid Management Experiment
    SFO     Space Flight Operations
    SFOC	Space Flight Operations Contract
    SFOM    Shuttle Flight Operations Manual
    SFOP    Safety Operating Procedure (KSC)
    SFP     Single Failure Point
    SFP     Summary Flight Plan
    SFPA    Single Failure Point Analysis
    SFPPL   Short Form Provisioning Parts List
    SFPS    Single Failure Point Summary
    SFS     Shuttle Flight Status
    SFSS    Satellite Field Service Station
    SFSS	SPARTAN Flight Support Structure
    SFT     Shaft
    SFT     Simulated Flight Test
    SFT     Static Firing Test
    SFTA    Structural Fatigue Test Article
    SFTF    Static Firing Test Facility
    SFTWE   Software
    SFU     Standard Firing Unit
    SFW     Software
    SFWE(M) Static Feed Water Electrolysis (Module)
    SG      Signal Generator
    SGC     Stabilized Ground Cloud
    SGG	Superconducting Gravity Gradiometer
    SGGM	Superconducting Gravity Gradiometer Mission
    SGL	Space Ground Link
    SGLS    Space Ground Link Station
    SGLS    Space Ground Link System
    SGMT    Simulated Greenwich Mean Time
    SGOS    Shuttle Ground Operations Simulation (Simulator)
    SGP     Single Ground Point
    SGS	Space Gateway Support
    SGS     Steep Glide Slope
    SGSC    Strain Gauge Signal Conditioner
    SH2     Supercritical Hydrogen
    SHA     Sidereal Hour Angle
    SHA     System Hazard Analysis
    SHAG    Simplified High Accuracy Guidance (Honeywell)
    SHAP	Sample Handling and Analysis Plan
    SHARE	Space Station Heat Pipe Advanced Radiation (STS-29)
    SHARE	Space Station Heat Pipe Advanced Radiation Element
    SHARP	Summer High School Apprenticeship Research Program
    SHDN    Shutdown
    SHE     Supercritical Helium
    SHEAL	Shuttle High Energy Astrophysics Laboratory
    SHERB   Sandia Human Error Rate Bank
    SHF     Super High Frequency
    SHLB    Simulation Hardware Load Boxes
    SHLC    Safety, Health and Leadership Council
    SHLD    Shield
    SHLDR   Shoulder
    SHOOT	Superfluid Helium On-Orbit Transfer
    SHORAN  Short Range Navigation
    SHP     Shaft Horsepower
    SHRD    Shroud
    SHRD    Supplemental Heat Rejection Devices
    SHS     Simulation Hardware System
    SHTR    Shutter
    SHUTDN  Shutdown
    SI      Center Support Operations (KSC Directorate)
    SI      International Systems of Units (ISU preferred)
    SI      Scientific Instrument
    SI      Solar Inertial
    SIA     Shuttle Induced Atmosphere
    SIA     Software Impact Assessment
    SIA     Solar Inertial Attitude
    SIAC    Safety Issue Assessment Center
    SIAP    System Integrity Assurance Program
    SID     Shuttle Integration Device
    SID     Simulator Interface Devices
    SID     Standard Interface Document
    SID     System Interface Document
    SIDT    Spacelab I/O Data Tape
    SIE     Shuttle Interface Equipment
    SIEM    Systems Integration Effort for MSFC
    SIES    Supervision, Inspection, Engineering, and Services
    SIG     Signal
    SIG     Special Investigation Groups
    SIG CONDR Signal Conditioner
    SIG GEN Signal Generator
    SIL     Silver
    SIL     Sound Interference Level
    SIL     Systems Integration Laboratory
    SILTS   Shuttle Infrared Leeside Temperature Sensing
    SIM     Scientific Instrumentation Module
    SIM     Simulate, Simulation
    SIMA    Small Incremental Motion Actuator
    SIMAS   Shuttle Information Management Accountability System
    SIMCOM  Simulation Complex
    SIMFAC  Simulation Facility
    SIMO    Simultaneously
    SIMR    Systems Integration Management Review
    SIMS    Shuttle Imaging Microwave System
    SIMS    Shuttle Inventory Management System
    SIMS	Still Image Management System
    SIMU    Simulated Inertial Measurement Unit
    SIN     Sine
    SINDA   Systems Improve Numerical Differencing Analyzer
    SIO     Serial Input/Output
    SIO     Systems Integration Office
    SIP     Scientific Instrument Package
    SIP     Separation Instrument Package
    SIP     Standard Interface Panel
    SIP     Strain Isolator Pad
    SIPE    Scientific Instrument Protective Enclosure
    SIPS    Small Instrument Pointing System
    SIR     Shuttle Imaging Radar
    SIR     Software Initiated Restart
    SIR     System Interface Requirements
    SIR     Systems Integration Review
    SIR-A   Shuttle Imaging Radar-A
    SIR-B   Shuttle Imaging Radar-B
    SIRD    Support Instrumentation Requirements Document
    SIRR    Software Integration Readiness Review
    SIRTF   Space Infrared Telescope Facility
    SIS     SAIL Interface System
    SIS     Scanning Imaging Spectrometer
    SIS     Serial Input Special
    SIS     Shuttle Information System
    SIS     Shuttle Interface Simulator
    SIS     Simulator Interface System (Subsystem)
    SIS     Software Implementation Specification
    SIS     Software Integrated Schedule
    SIS     Standard Interface Specification
    SIS     Superconducting-Insulating Superconducting
    SIS     Systems Integration Schedule
    SISS    Scientific Instrument Support Structure
    SISWG   STS Integrated Schedule Working Group
    SIT     Shuttle Integrated Test
    SIT     Shuttle Interface Test
    SIT     Situation
    SIT     Software Integrated Test
    SIT     SSV Integrated Test
    SIU     Signal Interface Unit
    SIV     Sieve
    SIVE    Shuttle Interface Verification Equipment
    SKD     Singer, Kearfott Division
    SKIRT   Shuttle Kientic Infrared Test
    SL      Sea Level
    SL      Seal
    SL      Service Level
    SL      Shelf Life
    SL      Sound Level
    SL      Spacelab
    SL&I    System Load and Initialization
    SL-D    German Spacelab
    SL-J    Japanese Spacelab
    SL-SS   Spacelab Subsystems
    SL-SSS  Spacelab Subsystem(s) Segment
    SLA     ERNO Spacelab Product Assurance Department
    SLA     Shuttle Laser Altimeter
    SLA     Super Light Ablator
    SLA     Support and Logistics Areas
    SLAC    Stanford Linear Accelerator Center
    SLAHTS  Stowage List and Hardware Tracking System
    SLAK    Spacelab Late Access Kit
    SLAM    Side Load Arrest Mechanism
    SLAR    Side Looking Airborne Radar
    SLC     Shuttle Launch Complex (VAFB)
    SLC     Space Launch Complex
    SLC     ERNO Spacelab Project Control
    SLCA    ERNO Spacelab Contract Administration
    SLCC    ERNO Spacelab Configuration Management
    SLCL    Shop/Lab Configuration Layout
    SLD     Stiff-Leg Derrick
    SLE     ERNO Spacelab Engineering
    SLEMU   Spacelab Engineering Model Unit
    SLF     Shuttle Landing Facility (OLF)
    SLF     Shuttle landing facility (KSC)
    SLI     ERNO Spacelab Integration and Test
    SLIC    Super Lightweight Interchangeable Carrier
    SLL     Shelf Life Limit
    SLM     Sound Level Meter
    SLN     ERNO Spacelab Payload
    SLO     ERNO Spacelab Operations
    SLOS    Star Line of Sight
    SLP     ERNO Spacelab Program Office
    SLPB    Spacelab Program Board
    SLRV    Shuttle Launched Research Vehicle
    SLS     Secondary Landing Site
    SLS     Secondary Mirror
    SLS     Sortie Lab Simulator
    SLS     Spacelab Simulator
    SLS     Spacelab Life Sciences
    SLS     Statement Level Simulator
    SLSA    Shuttle Logistics Support Aircraft
    SLSMS   Spacelab Support Module Simulator
    SLT     ERNO Spacelab Technology
    SLV     Space Launch Vehicle
    SM      Science Mission
    SM      Secondary Mirror
    SM      Service Model
    SM      Short Module
    SM      Shuttle Management (KSC)
    SM      Soft Manual
    SM      Stable Member
    SM      Support Module
    SM      Systems Management
    SM&S    Systems Management and Sequencing
    SM/PM   System Management/Performance Monitor
    SMA     Science Monitoring Area
    SMA     Secondary Mirror Assembly
    SMAB    Solid Motor Assembly Building
    SMAG    Star Magnitude
    SMART   Shuttle Meeting Action - Item Review Tracking
    SMATV   Satellite Master Antenna Television
    SMB     Space Meteorology Branch
    SMC     Scientific Manpower Commission
    SMCC    Shuttle Mission Control Center
    SMCH    Standard Mixed Cargo Harness
    SMCS    Separation Monitor and Control System
    SMCU    Separation Monitoring Control Unit
    SMD     Spacelab Mission Development
    SMD     Special Measuring Device
    SMD     Special Measuring Service
    SMDC    Shielded Mild Detonating Cord
    SME     Subject Matter Expert
    SMEAR   Span/Mission Evaluation Action Request
    SMES    Shuttle Mission Engineering Simulator
    SMES    Shuttle Mission Evaluation Simulation (Simulator)
    SMES    Superconduction Magnetic Energy Storage
    SMG     Spaceflight Meteorology Group
    SMIA    Serial Multiplexer Interface Adapter
    SMIDEX  Spacelab Middeck Experiments
    SMIR    Shuttle Multispectral Infrared Radiometer
    SML     Structure Mold Line
    SMM     Solar Maximum Mission
    SMM     Subsystem Measurement Management
    SMMD    Specimen Mass Measurement Device
    SMOC    Simulation Mission Operation Computer
    SMP     Software Management Plan
    SMP     Symmetric Multi-Processing
    SMPM    Structural Materials Property Manual
    SMPTRB  Shuttle Main Propulsion Test Requirement Board
    SMQ     Structure Module Qualification Test
    SMR     Source, Maintenance, and Recoverability (Code)
    SMRD    Spin Motor Rotational Detector
    SMRD    Spin Motor Run Discrete
    SMRM    Solar Maximum Repair Mission
    SMS     Separation Mechanism Subsystem
    SMS     Shuttle Mission Simulator
    SMS     Solar Maximum Satellite
    SMS     Space Motion Sickness
    SMS     Synchronous Meteorological Satellite
    SMS	Systems Management Server
    SMSCC   Shuttle Mission Simulator Computer Complex System
    SMSI    Standard Manned Space Flight Initiator (see NSI-I)
    SMT     Selective Message Transaction
    SMT     Surface Mount Technology
    SMTAS   Shuttle Model Test and Analysis System
    SMTF    Shuttle Mission Training Facility
    SMTP    Simple Mail Transfer Protocol
    SMU     Soft Mockup
    SMU     Speaker/Microphone Unit
    SMVP    Shuttle Master Verification Plan
    SMVRD   Shuttle Master Verification Requirements Document
    SMW     Standard Materials Worksheet
    SMY     Solar Maximum Year
    SN      Solar Network
    SN      Space Network
    SNF     System Noise Figure
    SNR     Signal-to-Noise Ratio
    SNS     Station Network Simulator
    SNSO    Space Nuclear Systems Office
    SNSR    Sensor
    SO      Station Operator
    SO      Support Operations (KSC Dir.)
    SO2     Sulphur Dioxide
    SOAR    Shuttle Orbital Applications and Requirements
    SOARS   Shuttle Operation Automated Reporting System
    SOATS   Support Operation Automated Training System
    SOC     Simulation Operations Center
    SOC     Simulation Operation Computer
    SOC     System Operating Concept
    SOC     System Option Controller
    SOCAR   Shuttle Operational Capability Assessment Report
    SOCC    Satellite Operations Control Center
    SOCH    Spacelab Orbiter Common Hardware
    SOCRD   Science Operations Center Requirements Document
    SOCS    Subsystem Operation and Checkout System
    SODB    Shuttle Operational Data Book
    SODB    Start of Data Block
    SODS    Shuttle Operational Data System
    SODS    Skylab Orbit-Deorbit System
    SOE     Science Operations Element
    SOE     Sequence of Events
    SOF     Safety of Flight
    SOFI    Spray-on Foam Insulation
    SOFIA   Stratospheric Observatory for Infrared Astronomy
    SOFT    Space Operations and Flight Techniques
    SOGS    Science Operations Ground System
    SOH     Start of Heading
    SOHO    Solar and Heliospheric Observatory
    SOIS    Spacelab/Orbiter Interface Simulator
    SOL     Solar
    SOL     Solenoid
    SOLCON  Solar Constant
    SOLN    Solution
    SOLSPEC Solar Spectrum
    SOM     Ship Operations Manager (NASA)
    SOM     Spares Optimization Model
    SOM     Standard Operating Manual
    SOMD    Space Operations Mission Directorate
    SOMF    Start of Minor Frame
    SOMS    Shuttle Orbiter Medical System
    SONET   Synchronous Optical Network
    SOP     Secondary Oxygen Pack
    SOP     Spacelab Opportunity Payload
    SOP     Standard Operating Procedure
    SOP     Subsystem(s) Operating Procedure
    SOP     Subsystem Operating Program
    SOP     Systems Operation Plan
    SOPC    Shuttle Operations and Planning Center
    SOPC    Shuttle Operations Planning Complex
    SOR     Specification Operational Requirement
    SOR     Stable Orbit Rendezvous
    SORD    Systems Operations and Requirements Document
    SORPTR  South Repeater
    SORTIE  Short Term Mission
    SOS     Serial Output Special
    SOS     Source of Supply
    SOS     Stabilized Optical Sight
    SOSC    Space Operations Support Center
    SOSM    Strap-on Solid Motor
    SOT     Science Operations Team
    SOT     Solar Optical Telescope
    SOT     Strap-on Tank
    SOTS    Suborbital Tank Separation
    SOUP    Solar Optical Universal Photopolarimeter
    SOV     Shut-off Valve
    SOV     Solenoid Operated Valve
    SOW     Start of Word
    SOW     Statement of Work
    SOW     Subdivision of Work
    SOX     Supercritical Oxygen
    SP      Shoulder Pitch
    SP      Shuttle Projects Office (KSC)
    SP      Signal Processor
    SP      Single Pole
    SP      Single Precision
    SP      Solar Physics
    SP      Spare
    SP      Spin
    SP      Standard or Peculiar
    SP      Static Pressure
    SP&S    Special Processes and Sequencing
    SP-AF   Air Force STS Liaison Office (KSC Shuttle)
    SP-AF   Air Force Support Office (KSC)
    SP-FGS  Flight and Ground Systems Office (KSC Shuttle)
    SP-ILS  Integrated Logistics Support Office (KSC Shuttle)
    SP-LMO  Logistics Management Office (KSC)
    SP-OPI  Operations Planning and Integration Office (KSC Shuttle)
    SP-OSO  Off-Site Offices (KSC Shuttle)
    SP-PAI  Project Assessment and Integration Staff (KSC)
    SP-PCO  Program Control Office (KSC Shuttle)
    SP-PMS  Performance Management Systems Office (KSC)
    SP-SMO  Site Management Office (KSC Shuttle)
    SPA     S-Band Power Amplifier
    SPA     Servo Power Amplifier
    SPA     Shared Peripheral Area
    SPA     Signal Processor Assembly
    SPA     Small Payload Accommodations
    SPA     Software Product Assurance
    SPA     Solar Panel Assembly
    SPA     Space Processing Application
    SPA     Spare Parts Analysis
    SPA     Steering Position Amplifier
    SPACE   Spacecraft Prelaunch Automatic Checkout Equipment
    SPAD    Subsystem Positioning Aid Device
    SPAD    Shuttle Payload Accommodation Document
    SPADS   Shuttle Problem Analysis Data System
    SPADS   Shuttle Problem Action Data System
    SPAF    Simulation Processor and Formatter
    SPAH    Spacelab Payload Accommodations Handbook
    SPAN    Spacecraft Analysis
    SPART   Space Research and Technology
    SPAS    Shuttle Pallet Satellite  (German)
    SPBK    Speed Brake
    SPC     Starting Point Code
    SPC     Shipping and Packing Cost
    SPC     Stored Program Command
    SPC     Synoptic Properties Code
    SPC     Shuttle processing contractor
    SPCC    STS Processing Control Center
    SPCU    Simulation Process Control Unit
    SPCW    Stored Program Command Word
    SPD     Standard Practice Directive
    SPD     Speed
    SPDR    Software Preliminary Design Review
    SPDB    Subsystem Power Distribution Box
    SPDBK   Speed Brake
    SPDCI   Standard Payload Display and Control Interface
    SPE     Solid Polymer Electrolysis
    SPE     Static Phase Error
    SPEARS	Shuttle Processing Electronic Archival & Retrieval System
    SPEC    Specialist Function
    SPEC    Specification
    SPEC    Standard Performance Evaluation Corporation
    SPECT   Spectrometer
    SPEE    Special Purpose End Effector
    SPF     Single Point Failure
    SPF     Software Production Facility
    SPF     Spacelab Processing Facility
    SPFA    Single Point Failure Analysis
    SPFP    Single Point Failure Potential
    SPG     Signal Point Ground
    SPG     Single Point Ground
    SPHER   Spherical
    SPI     Standard Practice Instruction
    SPI     Surface Position Indicator
    SPIAP   Shuttle/Payload Integration Activities Plan
    SPICE   Spacelab Payload Integration and Coordination in Europe
    SPIDF   Support Planning Identification File
    SPIDPO  Shuttle Payload Integration and Development Program Office (JSC)
    SPIF    Standard Payload Interface Facility
    SPIF    Shuttle Payload Integration Facility
    SPIF    Shuttle/POCC Interface Facility Function
    SPII    Shuttle Program Implementation Instruction
    SPIMS   Shuttle Program Information Management System
    SPIP    Solid Propulsion Integrity Program
    SPKR    Speaker
    SPL     Scratch Pad Line
    SPL     Serialized Parts List
    SPL     Sound Pressure Level
    SPL     System Programming Language
    SPLX    Simplex
    SPLY    Supply
    SPM     Subsystem Project Manager
    SPMS    Special Purpose Manipulator System
    SPN     Shuttle Project Notice (KSC)
    SPND    Suspend
    SPO     Spare Parts Order
    SPO     Shuttle Projects Office
    SPO     System Program Office
    SPOC    Shuttle Payload Operations Contractor
    SPOC    Single Point of Contact
    SPOM    STS Planning and Operations Management
    SPP     Science Power Platform
    SPP     Simulation Planning Panel
    SPP     Solar Physics Payload
    SPPIL   Shuttle Preferred Pyrotechnic Items List
    SPPL    Spare Parts Provisioning List
    SPPP    Spacelab Payloads Processing Project
    SPR     Software Problem Report
    SPR     Subcontractor Performance Review
    SPRAG   STS Payloads Requirements and Analysis Group
    SPRT    Sequential Probability Ratio Test
    SPS     Service Propulsion Subsystem
    SPS     Shuttle Procedures Simulator
    SPS     Statement of Prior Submission
    SPS     Samples per Second
    SPS     Secondary Propulsion System
    SPS     Solar Power Satellite
    SPT     Support
    SPT     Steering Position Transducer
    SPTD    Supplemental Provisioning Technical Documentation
    SPVPF   Shuttle Payload Vertical Processing Facility
    sq ft   Square Feet
    SQL     Squelch
    SQL     Structured Query Language
    SQUID	Superconducting Quantum Interference Device
    SQW     Square Wave
    SR      Scan Ratio
    SR      Shift Register
    SR      Standard Repair
    SR      Statement of Requirements
    SR      Status Register
    SR      Status Report
    SR      Status Review
    SR      Sunrise
    SR      Support Request
    SR      Support Room
    SR&Q    Safety, Reliability, and Quality
    SR&QA   Safety, Reliability, and Quality Assurance
    SRA     Spin Reference Axis
    SRA     Support Requirements Analysis
    SRAG    Space Radiation Analysis Group
    SRB     Solid Rocket Booster
    SRBAB   SRB Assembly Building
    SRBDF   SRB Disassembly Facility
    SRBPF   Solid Rocket Booster Processing Facility
    SRC     Sample Return Container
    SRCB    Software Requirements Change Board
    SRCB    Software Requirements Control Board
    SRCBD   Software Requirements Change Board Directive
    SRCBD   Software Requirements Control Board Directive
    SRCH    Search
    SRD     Shuttle Requirements Definition
    SRD     Shuttle Requirements Document
    SRD     Systems Requirements Document
    SRDH    Subsystems Requirement Definition Handbook
    SRDH    System Requirements Definition Handbook
    SRE     STDN Ranging Equipment
    SRF     Shuttle Refurbishment Facility
    SRH     Subsystems Requirements Handbook
    SRM     Specification Requirements Manual
    SRM     Standard Reference Material
    SRM     Solid Rocket Motor
    SRMC    Stimulus/Response Measurements Catalog
    SRN     Software Release Notice
    SRO     Supervisor Range Operations
    SRPA    Spherical Retarding Potential Analyzer
    SRR     Shuttle Requirements Review
    SRR     Site Readiness Review
    SRR     Software Requirements Review
    SRR     System Requirements Review
    SRS     Simulated Remote Station
    SRS     Software Requirements Specification
    SRS     Specification Revision Sheet
    SRS     Support Requirements System
    SRSF    SRB Receiving and Subassembly Facility
    SRSF    SRB Refurbishment and Subassembly Facility
    SRSR    Schedule and Resources Status Report
    SRSS    Shuttle Range Safety System
    SRT     Supporting Research and Technology
    SRT     Station Readiness Test
    SRT     Specification Requirements Table
    SRT     Special Rated Thrust
    SRT     Shuttle Requirements Traceability
    SRU     Shop-Replaceable Unit
    SRU     Shop Replacement Unit
    SRU     Space Replaceable Units
    SRVL    Survival
    SS      Shuttle System
    SS      Single Sideband
    SS      Single String
    SS      Space Shuttle
    SS      Space Station
    SS      Station Set
    SS      Subsystem
    SS      Sunset
    SS      System Software
    SS      System Specification
    SS      System Summary
    SS&A    Space Systems and Applications
    SSA     S-Band Single Access
    SSA     Shuttle Simulation Aircraft
    SSA     Space Suit Assembly
    SSA I/O GCOS Program Element Name
    SSAT    Shuttle Service and Access Tower
    SSAT    Space Shuttle Access Tower (now FSS)
    SSAT	Space Station Airlock Trainer
    SSB     Single Sideband
    SSB     Source Selection Board
    SSBC    Summary Sheet Bar Chart
    SSBUV   Shuttle Solar Backscatter Ultraviolet Instrument
    SSC     Scanning Shadow Camera
    SSC     Shuttle System Contractor
    SSC     Single-Stage Command
    SSC     Solid-Solution Cermet
    SSC     Stennis Space Center
    SSC     Subsystem Computer
    SSC     Subsystem Sequence Controller
    SSCA    Surface Sampler Control Assembly
    SSCC    Support Services Control Center
    SSCC    Space Station Control Center
    SSCE    Solid Surface Combustion Experiment
    SSCHS   Space Shuttle Cargo Handling System
    SSCL    Shuttle System Commonality List
    SSCP    Small Self-Contained Payloads
    SSCSP   Space Shuttle Crew Safety Panel
    SSD     Spacecraft Software Division
    SSD     System Summary Display
    SSDD    Software System Design Document
    SSDH    Subsystem Data Handbook
    SSDS    Space Station Data System
    SSE	Small Science Experiment
    SSE     Space Shuttle Engines
    SSE     Subsystem Element
    SSE     Subsystem Support Equipment
    SSEOS   Space Shuttle Engineering and Operations Support
    SSF     SRB Storage Facility
    SSFA	Space Station Furnace Facility
    SSFGSS  Space Shuttle Flight and Ground System Specification
    SSFL    Santa Susana Field Laboratory
    SSFMB   Space Station Freedom Manned Base
    SSFP    Space Station Freedom Program
    SSFS    Space Shuttle Functional Simulator
    SSHB    Station Set Handbook
    SSHPF   Space Station Hazardous Processing Facility
    SSI     Significant Structural Item
    SSIBD   Shuttle System Interface Block Diagram
    SSID    Shuttle Stowage Installation Drawing
    SSIP    Systems Software Interface Processing
    SSIS    Space Station Information System
    SSITP   Shuttle System Integrated Test Plan
    SSL     Secure Sockets Layer
    SSL     System Software Loader
    SSM     Sample Support Module
    SSM     Spacecraft Systems Monitor
    SSM     Subsystem Manager
    SSM     Support System Module
    SSM     Systems Support Module
    SSMB    Space Shuttle Maintenance Baseline
    SSME    Space Shuttle Main Engine
    SSMEC   Space Shuttle Main Engine Controller
    SSMECA  Space Shuttle Main Engine Controller Assembly
    SSMECA  SSME Controller Assembly
    SSO     Safety Signification Operation
    SSO     Source Selection Official
    SSO     Space Shuttle Orbiter
    SSO     Subsystem Operation (in Spacelab)
    SSO     Support System for OEX
    SSOP    Space Systems Operating Procedure(s)
    SSP     Small Sortie Payload
    SSP     Space Shuttle Program
    SSP     Standard Switch Panel
    SSPC    Spacelab Stored Program Command
    SSPD    Shuttle System Payload Data
    SSPD    Shuttle System Payload Definition (Study)
    SSPD    Shuttle System Payload Description
    SSPDA   Space Shuttle Payload Data Activity
    SSPDB   Subsystem Power Distribution Box
    SSPDS   Space Shuttle Payload Data Study
    SSPGSE  Space Shuttle Program Ground Support Equipment
    SSPM    Space Shuttle Program Manager
    SSPO    Space Shuttle Program Office
    SSPO    Space Shuttle Projects Office
    SSPP    System Safety Program Plan
    SSPPSG  Space Shuttle Payload Planning Steering Group
    SSPRO   Space Shuttle Program Resident Office
    SSPS    Space Shuttle Program schedule
    SSPTF   Santa Susana Propulsion Test Facility (see SSFL)
    SSPTS   Station to Shuttle Power Transfer System
    SSR     Shop Support Request
    SSR     Staff Support Room
    SSR     Station Set Requirement
    SSR     System Requirements Review
    SSRD    Station Set Requirements Documents
    SSRMS   Space Station Remote Manipulator System
    SSRN    System Software Reference Number
    SSRR    Station Set Requirements Review
    SSS     Sound Suppression System     
    SSS     Space Shuttle System
    SSS     Stage Separation Subsystem
    SSS     Station Set Specification
    SSS     Subsystem Segment
    SSSS    Space Shuttle System Specification
    SST     Single System Trainer
    SST     Spacecraft Systems Test
    SST     Structural Static Test
    SST     Subsystem Terminal on Spacelab
    SSTC    Space Shuttle Test Conductor
    SSTF    Space Station Training Facility
    SSTG    Space Shuttle Task Group
    SSTO    Single Stage To Orbit
    SSU     Space Station Utilization Office
    SSUS    Spinning Solid Upper Stage
    SSUS-A  SSUS for Atlas-Centaur Class Spacecraft
    SSUS-D  SSUS for Delta Class Spacecraft
    SSUSP   Spinning Solid Upper Stage Project
    SSV     Space Shuttle Vehicle
    ST      Self Test
    ST      Sequential Timer
    ST      Simplification Task
    ST      Space Telescope
    ST      Spacelab Technology
    ST      Special Tooling
    ST      Star Tracker
    ST      Starter
    ST      Static
    ST      Structural
    ST-ECF  Space Telescope European Coordinating Facility
    STA     Shuttle Training Aircraft
    STA     Static Test Article
    STA     Station
    STA     Structural Test Article
    STAB    Stabilize, Stabilizer
    STAC    Shuttle Task Activation Contractor
    STADAC  Station Data Acquisition and Control
    STADAN  Satellite Tracking and Data Acquisition Network
    STADAN  Space Tracking and Data Acquisition Network
    STADN   Space Tracking and Acquisition Network
    STADU   System Termination and Display Unit
    STAG    Shuttle Turnaround Analysis Group
    STAR    Scientific and Technical Report
    STAR    Shuttle Turnaround Analysis Report
    STARR   Schedule, Technical, and Resources Report
    STAS	Space Transportation Architecture Studies
    STAT    Statistics
    STAT    Status
    STBD    Starboard
    STBE	Space Transportation Booster Engine
    STBY    Standby
    STC     Satellite Test Center
    STC     Spacecraft Test Conductor
    STC     Standard Test Configuration
    STC     Systems Test Complex
    STCP    Short-Term Cost Plan
    STD     Shuttle Test Director
    STD     Standard
    STDCE	Surface Tension Driven Convection Experiment
    STDCF	Space Telescope Data Capture Facility
    STDL    Standard Distribution List (letter denoting which list follows)
    STDN    Space Tracking and Data Network
    STDN    Spaceflight Tracking and Data Network
    STDY    Steady
    STE     Special Test Equipment
    STE     System Test Engineer
    STEP	Space Technology Experiments Platform
    STEREO  Solar Terrestrial Relations Observatories
    STEX	Sensor Technology Experiment
    STF     Spin Test Facility (see DSTF)
    STF     Structural Fatigue Test
    STG     Stage
    STICS	Suprathermal Ion Composition Spectrometer
    STIL    Software Test and Integration Laboratory
    STIRD   SAIL Test Implementation Requirements Document
    STL     Space Technology Laboratories
    STLOS   Star Line of Sight
    STM     Signal Termination Module
    STN     Software Trouble Note
    STM     Static Test Model
    STM     Support Test Manager
    STME	Space Transportation Main Engine
    STN	Software Trouble Note
    STO     Stow
    STOCC   Space Telescope Operations Control Center
    STP     Self-Test Program
    STP     Shuttle Technology Panel
    STP     Space Technology Payload
    STP     Space Test Program
    STP     Subsystem Test Plan
    STPH    Static Phase Error
    STR     Structure
    STR     System Test Review
    STRL    Structural
    STRB    Strobe
    STRCH   Stretch
    STRFLD  Star Field
    STRG    Steering
    STRG    String
    STRUC   Structure
    STRUCT  Structure
    STS     Shuttle Test Station
    STS     Space Transportation System (formal name for the Space Shuttle)
    STS     Structural Transition Section
    STSR    System Test Summary Report
    STSG    Shuttle Test Group
    STSOPO  Shuttle Transportation Systems Operations Program Office (JSC)
    STT     Spacelab Transfer Tunnel
    STU     Shuttle Test Unit
    STU     Special Test Unit
    STU     Star Tracker Unit
    STV     Space Transfer Vehicle
    SU      Support Unit
    SUB     Substitute
    SUBJ    Subject
    SUM     Summary
    SUMC    Space Ultrareliable Modular Computer
    SUMM    Summary
    SUMS    Shuttle Upper-Atmosphere Mass Spectrometer
    SUP     Supply
    SUP     Support
    SUPCRIT Supercritical
    SUPPR   Suppression
    SUPSALV Supervisor of Salvage (U.S. Navy)
    SUPT    Support
    SUPV    Supervisor
    SURE    Shuttle Users Review and Evaluation
    SURF    Surface
    SURS    Standard Umbilical Retraction System
    SUSIM   Solar Ultraviolet Spectral Irradiance Monitor
    SUTAGS  Shuttle Uplink Text and Graphics Scanner
    SV      Safety Valve
    SV      Solemoid Valve
    SV      Shuttle Vehicle
    SV      Space Vehicle
    SV      Stator Vector
    SVA&C   Shuttle Vehicle Assembly and Checkout
    SVAB    Shuttle Vehicle Assembly Building
    SVAC    Shuttle Vehicle Assembly and Checkout (Facility)
    SVAFB   South Vandenberg Air Force Base
    SVB     Shuttle Vehicle Booster
    SVB     Space Vehicle Booster
    SVC     Supervisor Call
    SVDS    Space Vehicle Dynamic Simulator
    SVM     Sensor Verification Mechanism
    SVO     Space Vehicle Operations (KSC Dir.)
    SVRR    Software Verification Readiness Review
    SVS     Space Vision System
    SVS     Suit Ventilation System
    SW      Sea Water
    SW      Short Wave
    SW      Software (SFTWE preferred)
    SW      Solar Wing
    SW      Status Word
    SW      Switcher (Switch)
    SW/PM   System Management/Performance Monitor
    SWA     Support Work Authorization
    SWAA    Spacelab Window Adapter Assembly
    SWAD    Subdivision of Work Authorization Document
    SWAT    Stress Wave Analysis Technique
    SWG     Software Working Group
    SWICS   Solar-Wind Ion-Composition Spectrometer
    SWOB    Salaries, Wages, Overhead, and Benefits
    SWP     Safe Working Pressure
    SWR     Standing Wave Ratio
    SWS     Switch Scan
    SWT     Supersonic Wind Tunnel
    SXT     Sextant
    SY      Shoulder Yaw
    SY      System
    SYM     Symbol
    SYMM    Symmetrical
    SYN     Synchronous
    SYN     Synthetic
    SYNC    Synchronize
    SYNCOM  Hughes Spin Stabilized Spacecraft
    SYNCOM  Synchronous Communication Satellite (Hughes)
    SYS     System
    SYSTRAN Systems Analysis Translator
    
    T
    
    T       Talk/Monitor
    T       Temperature
    T       Temperature Rate
    T       Test
    T       Thermostabilized
    T       Throttle Command
    T       Time (liftoff)
    T       Top
    T       Total Temperature
    T       Transformation (Matrix), Transpose (Matrix Superscript)
    T=      Time Equivalent (used for duration of event)
    T&C     Telemetry and Command
    T&CD    Timing and Countdown
    T&CP    Test and Checkout Procedure
    T&D     Transportation and Docking
    T&E     Test and Evaluation
    T&M     Time and Materials
    T&O     Test and Operations
    T&V     Test and Verification
    T+      Time Postintegration
    T-      Time Prior to Launch
    T-0     Time Zero
    T-0     Takeoff
    T.B.    Toggle Buffer
    T.P.    Transition Period
    T/A     Turnaround
    T/C     Telecommunications
    T/C     Temperature Compensating
    T/C     Termination Check
    T/C     Thrust Chamber
    T/CAP   Thermal Capacitor
    T/D     Time Delay
    T/D     Touchdown
    T/E     Transporter/Erector
    T/L     Talk and Listen
    T/L     Timeline
    T/L     Transformer Load
    T/O     Takeover
    T/R     Tape Recorder
    T/R     Technical Report
    T/R     Transformer Rectifier
    T/R     Transmit/Receive
    T/R     Transmitter/Receiver
    T/R     Transportation Request
    T/R     Turnaround RequiremLnts
    T/T     Terminal Timing
    T/T     Timing/Telemetry
    T/TCA   Thrust/Translation Control Assembly
    T/V     Thermal Vacuum
    T/W     Thrust Weight
    T/W     Thrust-to-Weight
    TA      Task Agreement
    TA      Task Analysis
    TA      Test Article
    TA      Time Actual
    TA      Travel Authorization
    TA      Trunnion Angle
    TAA     Technical Assistance Agreement
    TAA     Temporary Access Authorization
    TAA     Temporary Area Access
    TAC     Kennedy Space Center Landing Site, Florida
    TAC     Tactical Air Command
    TAC     Total Average Cost
    TAC/RA  TACAN Radar Altimeter
    TACAN   Tactical Air Command and Navigation System
    TACAN   Tactical Air Navigation
    TACH    Tachometer
    TACO    Test and Checkout Operations
    TAD     Temperature and Dewpoint
    TAEM    Terminal Area Energy Management
    TAG     Technical Air-to-Ground
    TAGS    Text and Graphics System
    TAIR    Test Assembly Inspection Record
    TAL     Transatlantic Abort Landing
    TAL     Transoceanic Abort Landing
    TALAR   Tactical Approach and Landing Radar
    TAM     Thermal Analytical Model
    TAN     Tananarive, Madagascar (STDN Site)
    TAO     Trans-Atlantic Abort
    TAP     Technical Achievement Plan
    TAP     Telemetry Acceptance Pattern
    TAP     Test Administration Plan
    TAP     Total Air Pressure
    TAR     Technical Analysis Request
    TAR     Test Action Requirement
    TAR     Test Agency Report
    TAS     Telemetry Antenna Subsystem
    TAS     Test Article Specification
    TAS     Tether Applications in Space
    TAS     True Airspeed
    TARC    Through Axis Rotational Control
    TASPR   Technical and Schedule Performance Report
    TASPR   Total Air Temperature
    TASPR   Turnaround Time
    TATI    Total Air Temperature Indicator
    TAT     Technical Acceptance Team
    TB      Talk Back
    TB      Terminal Base
    TB      Terminal Board
    TB      Time Base
    TB      Time Duration of Burn
    TB      Toggle Buffer
    TBA     To Be Added
    TBA     To Be Announced
    TBC     Terminal Buffer Controller
    TBD     To Be Defined
    TBD     To Be Determined
    TBD     To Be Developed
    TBE     To Be Escorted
    TBE     To Be Evaluated
    TBF     Test de Bon Fonctionnement (Spacelab)
    TBI     Through-Bulkhead Initiator
    TBN     To Be Negotiated
    TBP     To Be Provided
    TBS     Task Breakdown Structure
    TBS     To Be Specified
    TBS     To Be Superseded
    TC      Telecommunications
    TC      Temperature Compensating
    TC      Test Conductor (Contractor)
    TC      Test Conductor (Controller)
    TC      Thermal Control
    TC      Thermocouple
    TC      Thiokol Corporation
    TC      Thrust Chamber
    TC      Time to Circular
    TC      Traceability Code
    TC      Tracking Camera
    TCA     Time of Closest Approach
    TCA     Thrust Chamber Assembly
    TCA     Translation Controller Assembly
    TCAB    Temperature of Cabin
    TCC     Test Control Center
    TCC     Thermal Control Coating
    TCD     Test Completion Date
    TCD     Test Control Document
    TCDT    Terminal Countdown Demonstration Test
    TCE     Thermal Canister Experiment
    TCF     Tank Checkout Facility
    TCG     Test Control Group
    TCG     Time Code Generator
    TCI     Technical Critical Item
    TCID    Test Configuration Identifier Document
    TCID	Test Control Identifier
    TCIR	Total Case Incident Rate
    TCMD    Transportation Control and Movement Document
    TCMS    Test, Control and Monitor System
    TCN     Test Change Notice
    TCN     Transportation Control Number
    TCO     Taken Care Of
    TCO     Test and Checkout
    TCOP    Test Checkout Plan(s)
    TCP     Task Control Packet
    TCP     Test Checkout Procedure
    TCP     Test Control Package
    TCP     Thrust Chamber Pressure
    TCP     Transmission Control Protocol
    TCP/IP  Transmission Control Protocol/Internet Protocol
    TCR     Test Compare Results
    TCR     Test Conductor
    TCR     Test Constraints Review
    TCR     Thermal Concept Review
    TCRSD   Test and Checkout Requirements Spec. Documentation
    TCS     Technical Change Summary
    TCS     Technical Concurrence Sheets
    TCS     Test Control Supervisor
    TCS     Test Control System
    TCS     Thermal Control System (Subsystem)
    TCSSS   Thermal Control Subsystem Segment
    TCTI    Time Compliance Technical Instruction
    TCTO    Time Compliance Technical Order
    TCU     Tape Control Unit
    TCV     Temperature Control Voltage
    TCV     Thrust Chamber Valve
    TD      Technical Directive
    TD      Terminal Distributor
    TD      Test Director (NASA)
    TD      Time Delay
    TD      Touch Down
    TD&SA   Telephone, Data, and Special Audio
    TDD     Task Description Document
    TDM     Time-Division Multiplexing (Multiplexer)
    TDP     Temperature and Dewpoint
    TDP     Tracking Data Processor
    TDR     Technical Design Review
    TDR     Technical Documentation Report
    TDR     Test Discrepancy Report
    TDRR    Test Data Recording and Retrieval
    TDRS    Telemetry Downlist Receiving Site
    TDRS    Tracking and Data Relay Satellite
    TDRSS   Tracking and Data Relay Satellite System
    TDS     Technology Demonstration Satellite
    TDS     Test Data System
    TDU     Time Display Unit
    TDV     Test Data Van
    TDY     Temporary Duty
    TE      Test Equipment
    TE      Time Earliest/Expected
    TE      Timing Electronics
    TE      Trailing Edge
    TEC     Test Equipment Center
    TECH    Technical
    TECH    Technician
    TED     Trailing Edge Down
    TELCOM  Telecommunications
    TELESAT TELESAT (Canadian Payload, Communication Satellite)
    TEMP    Temperature
    TEMP    Test and Evaluation Master Plan
    TEMS    Transport Environment Monitoring System
    TEOS    Tetraethyl Orthosilicate
    TEP     Technical Evaluation Panel
    TEP     Test Evaluation Plan
    TER     Test Equipment Readiness
    TER     Time Estimating Relationship
    TERL    Test Engineer Readiness List
    TERL    Test Equipment Readiness List
    TERM    Terminate
    TESH    Technical Shop
    TET     Test Evaluation Team
    TF      Test Facility
    TF      Test Fixture
    TFC     Time From Cutoff
    TFCS    Triplex Flight Control System (Subsystem)
    TFE     Time From Event
    TFF     Time to Free Fall
    TFI     Time From Ignition
    TFL     Telemetry Format Load
    TFL     Time From Launch
    TFOV    Total Field of View
    TFR     Trouble and Failure Report
    TFS     Telemetry Format Selection
    TFU     Test Facility Utilization
    TG      Ground Systems (KSC Directorate)
    TG      Ground Systems, TS
    TGA     Thermal Gravimetric Analysis
    TGA     Trace Gas Analyzer
    TGO     Time to Go
    TGOWG   Teleoperator Ground Operations Working Group
    TGS     Rate Gyro Assembly
    TGS     Telemetry Ground Station
    TGS     Telemetry Ground System
    TGS     Triglycine Sulfate
    TGSE    Telemetry Ground Support Equipment
    TGT     Target
    THC     Translation Hand Controller
    THC     Translational Hand Controller
    THDS    Time Homogeneous Data Set
    THEMIS  Time History of Events and Macroscale Interactions During Substorms
    THEO    Theoretical
    THERM   Thermal
    THOLD   Threshold
    THOUS   Thousand
    THP     Thrust Horsepower
    THROT   Throttle
    TI      Information Systems (KSC Directorate)
    TI      Technical Integration
    TI      Terminal Initiation Rendezvous Maneuver
    TI      Training Integrator (Integration)
    TIC     Technical Information Center
    TIC     Total Item Change
    TICM    Test Interface and Control Module
    TIE     Technical Integration Engineer
    TIFS    Total In-Flight Simulator
    TIG     Time of Ignition
    TII     Tooling Inspection Instrumentation
    TIM     Technical Interchange Meeting
    TIM     Time Interval Monitor
    TIO     Target Insertion Orbit
    TIP     Thrust Inlet Pressure
    TIP	Time Interval Processor
    TIROS   Topographical Infrared Operations Satellite
    TIS     Test Interface Subsystem
    TISRS	Tether Initiated Space Recovery System
    TISP	Teacher in Space Project
    TK      Tank
    TKSC	Tsukuba Space Center
    TL      Thrust Level
    TL      Time Latest
    TL      Traceability Lot
    TL      Transient Load
    TLC     Telecommand
    TLCE    Transmission Line Conditioning Equipment
    TLD	Thermoluminescent Dosimeter
    TLM     Telemetry
    TLS     Time Line Sheet
    TLS     Top Left Side
    TLS     Transport Layer Security
    TLSA    Torso Limb Suit Assembly
    TLSCP   Telescope
    TLV     Threshold Limit Value
    TLV     Transporter-Loader Vehicle
    TM      Member Traceability
    TM      Table Maintenance
    TM      Technical Management
    TM      Telemetry
    TM      Time Management
    TM      Traffic Model
    TMA	Technology Mirror Assembly
    TMB     Transportation Management Bulletin
    TMBU    Table Maintenance Block Update
    TMC     Test Monitoring Console
    TMECO   Time of Main Engine Cutoff
    TMF     Transporter Maintenance Facility
    TMG     Thermal Meteoroid Garment
    TMI     Technical Management Items
    TML	Total Mass Loss
    TMM	Thermal Math Model
    TMO     Test Manufacturing Order
    TMO     Tool Manufacturing Order
    TMP     Terminal Panel
    TMP     Time Management Processor
    TMPRY   Temporary
    TMPV    Torquemotor Pilot Valve
    TMR     Timer
    TMU     Temperature Measurement Unit
    TMV	Thermal Margin Verification
    TN      Technical Note
    TNL     Tunnel
    TNT     Trinitrotoluene
    TO      Operations Management (KSC Directorate)
    TO      Operations Management (TS)
    TO      Takeoff
    TO      Task Order
    TO      Technical Order
    TOC     Test Operations Center
    TOC     Test Operations Change
    TOC     Total Organic Carbon
    TOF     Test Operations Facility
    TOG     Toggle
    TOGA	Tropical Ocean Global Atmosphere
    TOI     Transfer Orbit Insertion
    TOL     Tolerance
    TOO     Test Operations Order
    TOO     Threshold of Odor
    TOP     Technical Operating Procedure
    TOP	Tether Optical Phenomena
    TOPEX	Topographical Explorer
    TOPS    Transistorized Operational Phone System
    TOS     Test Operating System
    TOS	Transfer Orbit Stage
    TOT     Total
    TOW     Tank and Orbiter Weight
    TP      Test Point
    TP      Test Port
    TP      Test Procedure
    TP      Time to Perigee
    TP      Training Plan
    TP      Transition Period (T.P. preferred)
    TP      True Position
    TP      Turbo Pump
    TP      Type
    TP&C    Thermal Protection and Control
    TPA     Test Preparation Area
    TPA     Tilt Platform Assembly
    TPAD    Trunnion Pin Attachment Device
    TPC     Telemetry Preprocessor Computer
    TPDS    Test Procedures Development System
    TPE     Test Project Engineer
    TPF     Terminal Phase Finalization (Braking)
    TPF     Terminal Phase Finish
    TPF     Transfer Phase Final
    TPF     Tug Processing Facility
    TPI     Terminal Phase Initiation
    TPM     Technical Performance Measurement (System)
    TPM     Terminal Phase Maneuver
    TPM     Terminal Phase Midcourse
    TPM     Transfer Phase Midcourse
    TPM1    Terminal Phase Midcourse #1
    TPM2    Terminal Phase Midcourse #2
    TPO     Test Program Outline
    TPR     Teleprinter
    TPR     Test Problem Report
    TPS     Test Preparation Sheet
    TPS     Thermal Protection Subsystem
    TPS     Thermal Protection System (SRB, ET, or Orbiter)
    TPS     Twisted Pair Shielded
    TPSE    Thermal Protection Subsystem Experiments
    TPUN    Test Procedure Update Notice
    TR      Technical Report
    TR      Technical Review
    TR      Test Request
    TR      Thrust Reverser
    TR      Time to Retrofire
    TR      Transportation Request
    TR/SBS  Teleoperator Retrieval/Skylab Boost System
    TR1     Payload Furnished Mars Tape Recorder (1 of 2)
    TR2     Payload Furnished Mars Tape Recorder (2 of 2)
    TRA     Training Requirements Analysis
    TRA     Turnaround Requirements Analysis
    TRACS   Tool-Record Accountability System
    TRAJ    Trajectory
    TRANS   Transition
    TRANS   Translation
    TRANSL  Translation
    TRB     Technical Review Board
    TRB     Test Review  Board
    TRBL    Troubleshooting
    TRCP    Tape Recorder Control Panel (LIO)
    TRD     Test Requirements Document
    TReK    Telescience Resource Kit
    TRF     Tuned Radio Frequency
    TRK     Track
    TRKR    Tracker
    TRL     Test Readiness List
    TRN     Trunnion
    TRNG    Training
    TRP	Technical Review Panel
    TRQ     Torque
    TRR     Test Readiness Review
    TRRB    Test Readiness Review Board
    TRS     Teleoperator Retrieval System
    TRS     Time Reference System
    TRS     Top Right Side
    TRS     Troubleshooting Record Sheet
    TRS     Tug Rotational System
    TRSD    Test Requirements Specification Document
    TRUN ANG Trunnion Angle
    TS      Technical Support (KSC Directorate)
    TS      Tensile Strength
    TS      Test Site
    TS      Test Stand
    TS      Test Station
    TS      Time Scheduled
    TS      Timing System
    TS      Traceability Serial
    TSA     Test Start Approval
    TSAC    Tracking System Analytical Calibration
    TSB     Temporary Stowage Bag
    TSB     Twin Sideband
    TSC     Test Setup Complete
    TSC     Test Support Coordinator
    TSC     Two-Stage Command
    TSCION  TSC 1/0 Number
    TSCO    Test Support Coordination Office
    TSCO    Test Support Coordinator
    TSCP    Training Simulator Control Panel
    TSD     Test Start Date
    TSE     Transportation Support Equipment
    TSGP    Test Sequence Generator Program (ESTEC)
    TSLD    Troubleshooting Logic Diagram
    TSM     Tail Service Mast
    TSM     Trade Study Management
    TSO     Time Sharing Option
    TSO     Time Since Overhaul
    TSP     Test Software Program
    TSP     Twisted Shielded Pairs (Cables)
    TSR     Technical Status Review
    TSR     Test Status Report
    TSRA    Total System Requirements Analysis
    TSS     Time Sharing System
    TSS     TPS Summary Sheet Control
    TSS     Tug Structural Support
    TSSU    Test Signal Switching Unit
    TST     Test
    TSU     Time Standard Unit
    TSW     Test Software
    TSW     Test Switch
    TT      Terminal Timing
    TT      Thrust Termination
    TT      Total Temperature
    TT      Total Time
    TT&C    Tracking, Telemetry and Command
    TT&C    Tracking, Telemetry and Control
    TTA     Time to Apogee
    TTA     Thermomechanical Test Area
    TTC     Time To Circularize (Orbit)
    TTC     Telemetry, Tracking, and Command
    TTC     Tunnel Thermal Control
    TTCA    Thrust Translation Controller Assembly
    TTCV    Tracking Telemetry, Command, and Voice
    TTE     Time To Event
    TTEL    Tool and Test Equipment List
    TTG     Time To Go
    TTL     Transistor-Transistor Logic
    TTLM    Through-the-Lens Light Metering
    TTP     Time To Perigee
    TTSS    Technical Training Scheduling System - (USA)
    TTSS    Training Tracking Scheduling System - (PGOC)
    TTU     Timing Terminal Unit
    TTV     Termination, Test, and Verification
    TTY     Teletype
    TU      Technical Utilization
    TU      Technology Utilization
    TU      Transport Unit
    TUL     Tula Peak, NM (STDN site)
    TURB    Turbine
    TV      Television
    TV      Thermal Vacuum
    TV      Thrust Vector
    TV      Transport Vehicle
    TVA     Thrust Vector Alignment
    TVAR    Test Variance
    TVC     Thermal Vacuum Chamber
    TVC     Thrust Vector Control
    TVCA    Thrust Vector Control Actuator
    TVCD    Thrust Vector Control Driver
    TVCS    Thrust Vector Control System
    TVEXPIS TV Experiment Interconnecting Station
    TVN     Test Verification Network
    TVP     Test Verification Program
    TVS     Toxic Vapor Suit
    TVSA    Thrust Vector Control Servoamplifier
    TVSSIS  TV Subsystem Interconnecting Station
    TVT     Thermal Vacuum Test
    TVTA    Thermal Vacuum Test Article
    TW      Tailwind
    TW      Thumbwheel
    TW      Time Words
    TW      Traveling Wave
    TWD     Twisted Double Shielded
    TWG     Test Working Group
    TWL     Total Weight Loss
    TWR     Tower
    TWT     Traveling Wave Tube
    TWT     Trisonic Wind Tunnel (Rockwell)
    TWTA    Traveling Wave Tube Amplifier
    TWU     Transport Workers' Union
    TWX     Teletype Wire Transmission
    TX      Translation Hand Controller X-Axis Direction
    TX      Transmit Channel
    TX/RX   Transmitter/Receiver
    TY      Translation Hand Controller Y-Axis Direction
    TYP     Typical
    TZ      Translation Hand Controller Z-Axis Direction
    
    U
    
    U       Underfloor
    U       Uranium
    U-SB    Unified S-Band
    U/C     Under Current
    U/D     Update
    U/L     Uplink (UPLK preferred)
    U/M     Unit of Measure
    U/M     Unmanned
    U/M     Unscheduled Maintenance
    U/O     Used on
    U/S     Upper Stage
    U/S     Upstream
    U/V     Under Voltage
    U/W     Used with
    UA      Microampere
    UAB     University of Alabama in Birmingham
    UARS    Upper Atmosphere Research Satellite
    UB      Upper Brace
    UB      Utility Bridge
    UBE     Universal Bus Exercisor
    UBIC    Universal Bus Interface Controller
    UC      Unsatisfactory Condition
    UCC     Universal Checkout Console
    UCD     Urine Collection Device
    UCN     Uniform Control Number
    UCPU    Urine Collection and Pretreatment Unit
    UCR     Unsatisfactory Condition Report
    UCS	Unified Control System
    UCS     Uniform Coding System
    UCS     Universal Control System
    UCS     Utilities Control System
    UCTA    Urine Collection Transfer Assembly
    UD      Update
    UDB     Update Buffer
    UDF     Utility and Data Flow
    UDL     Updata Link
    UDL     Update Link
    UDMH    Unsymmetrical Dimethylhydrazine
    UDMH/H  Unsymmetrical Dimethylhydrazine Hydrazine Blend
    UDOP    Ultrahigh Doppler
    UDS     Universal Documentation System
    UER     Unique Equipment Register
    UF      Microfarad
    UFD     User File Directory
    UG      Microgram
    UHB     User Home Base
    UHF     Ultrahigh Frequency
    UHV     Ultrahigh Vacuum
    UI      Unit of Issue
    UI      User Interface
    UIC     User Identification Code
    UIO     User Integration Office
    UIT     Ultraviolet Imaging Telescope
    UKIRT   United Kingdom Infrared Telescope
    UL      Underload
    UL      Uplink
    UL      Upper Left (S-Band Antenna)
    UL      Upper Limit
    ULA     Fairbanks, Alaska (STDN Site)
    ULC     Unpressurized Logistics Center
    ULE     Ultralow Expansion
    ULEP    Useful Life Extension Program
    ULL     Ullage
    ULO     Unmanned Launch Operations
    ULT     Ultimate
    ULT     Ultimate Load Test
    ULVIM   Ultraviolet Limb Imaging
    UMB     Umbilical
    UMBC    Umbilical Cord Cable
    UMI     Urine Monitoring Investigation
    UMO     Unmanned Orbital
    UMS     Urine Monitoring System
    UMVF    Unmanned Vertical Flight
    UNBAL   Unbalance
    UNDK    Undock
    UNDV    Undervoltage
    UNISAT  United Satellite LTD
    UNIV    Universal
    UNLCH   Unlatch
    UNLK    Unlock
    UOF     User Operations Facility
    UP	Unsolicited Proposal
    UP      Upper
    UPLK    Uplink
    UPN     Unique Project Number
    UPP     User Parameter Processing
    UPS     Uninterruptible Power Supply
    UPS     Uninterruptible Power System
    UPS     Upright Perigee Stage
    UPTLM   Uplink Telemetry
    UR      Unsatisfactory Report
    UR      Upper Right
    UR      User Room
    URA     Uniformly Redundant Array
    URA     Urine Receptacle Assembly
    URD     User Requirements Document
    URN     Urine
    URT     Upright
    US      United States
    US      Upper Stage
    USA     United Space Alliance
    USA     United States of America
    USA     Upper Stage Adapter
    USAF    United States Air Force
    USAFA   United States Air Force Academy
    USB     Unified S-Band
    USB     Upper Side Band
    USBE    Unified S-Band Equipment
    USBI    United Space Boosters, Inc.
    USBS    Unified S-Band System (Subsystem)
    USC     United States Code
    USDA    United States Department of Agriculture
    USE     User Support Equipment
    USEC    Microsecond
    USGS    United States Geological Survey
    USI     Update Software Identity
    USICU   United States ISPR Checkout Unit
    USMC    United States Marine Corps
    USML    United States Microgravity Laboratory
    USMP    United States Microgravity Payload
    USN     United States Navy
    USNS    United States Navy Ship
    USOC    User Support and Operations Center
    USR     User Support Room
    USRA    Universities Space Research Association
    USS     United States Ship
    USS     United States Standard
    USS     Utility Support Structure
    UST     United States Testing (Company)
    UST     Universal Servicing Tool
    UST     Universal Standard Time
    USTDC	University-affiliated Spaceport Technology Development Contract
    USV     Upper Stage Vehicle
    UT      Umbilical Tower
    UT      Unit Tester
    UT      Universal Time
    UT&GS   Uplink Text and Graphics System
    UTC     Unit Test Cases
    UTC     United Technologies Corporation
    UTC     United Technology Center
    UTC     Universal Test Console
    UTC     Universal Time Coordinated 
    UTE     Universal Test Equipment
    UTIL    Utility
    UTLM    Up Telemetry
    UTRC    United Technology Research Center
    UTS     Ultimate Tensile Strength
    UTS     Urine Transfer System
    UU      Micromicron (name micron obsolete); use um (micrometer)
    UUPIC   Universal Uniform Personal Identification Code
    UUT     Unit Under Test
    UV      Microvolt (mV)
    UV      Ultraviolet
    UV      Under Voltage (U/V preferred)
    UVD     Under Voltage Device
    UVF     Unmanned Vertical Flight
    UVS     Unmanned Vehicle System
    UVSP    Ultraviolet Spectrometer and Polarimeter
    UVX     Ultraviolet Cosmic Background Experiment
    UW      Microwatt
    UWS     User Work Station
    
    V
    
    V       Valve
    V       Velocity
    V       Verb
    V       Voice
    V       Volt
    V       Voltage
    V P-P   Voltage Peak-to-Peak
    V&DA    Video and Data Acquisition
    V&DA    Video and Data (Processing) Assembly
    V&V     Validation and Verification
    V-A     Vibro-Acoustic
    V-A     Volt-Ampere
    V-BAR   Velocity Vectory Axis
    V-CITE  Vertical-Cargo Integration Test Equipment
    V-RTIF  Vandenberg Real Time Interface
    V/A     video/Analog
    V/C     Vector Control
    V/C     Velocity Counter
    V/H     Velocity-to-Height
    V/M     Velocity Meter
    V/V     Vent Valve
    V/V     Validation and Verification (also V&V)
    VA      Vibro-Acoustic Test
    VA      Velocity at Apogee
    VA      Volt Ampere
    VA/T/VTA Vibro-Acoustic/Thermal/Vacuum Test Article
    VAA     Viewpoint Adapter Assembly
    VAA     Vehicle Assembly Area
    VAB     Vehicle Assembly Building
    VAB     Vehicle Assembly Building
    VAC     Volts, ac
    VAC     Vehicle Assembly and Checkout
    VAC     Vacuum
    VAD     Vandenberg Addendum Document
    VAFB    Vandenberg Air Force Base
    VAK     Vertical Access Kit
    VAK     Vertical Assembly Kit
    VAL     Valid
    VALID   Validation
    VAN     USNS Vanguard (STDN)
    VAP     Vapor
    VAR     Variable, Variance, Variation
    VAR     Verification Analysis  Report
    VAR     Volt Ampere Reactive
    VARM    Vehicle Accident Report Meeting
    VASI    Visual Approach Slope Indicator
    VAST    Versatile Avionics System Tester
    VAT     Vibro-Acoustic Test
    VATA    Vibro-Acoustic Test Article
    VATF    Vibration and Acoustic Test Facility
    VBSP    Video Baseband Signal Processor
    VC      Vector Character
    VC      Velocity Counter
    VC      Virtual Circuit
    VCAP    Vehicle Charging and Potential Experiment
    VCB     Vertical Location of the Center of Buoyancy
    VCC     Verification Code Counter
    VCD     Verification Control Document
    VCD(S)  Vapor Compression Distillation (Subsystem)
    VCE     Vehic
    VCG     Vapor Crystal Growth
    VCG     Vector Cardiogram
    VCG     Vertical Location of the Center of Gravity
    VCGS    Vapor Crystal Growth System
    VCI     Velocity Change Indicator
    VCM     Volatile Condensable Material
    VCN     Verification Completion Notice
    VCO     Voltage Controlled Oscillator (Oscillation)
    VCP     Vandenberg Contract Report
    VCR     Verification Complete Reports
    VCR     Video Cassette Recorder
    VCRS    Video Compression and Reconstruction System
    VCS     Verification Control Sheet
    VCS     Voice Command System
    VCT     Voltage Control Transfer
    VCTR    Vector
    VCU     Video Control Unit
    VDA     Valve Driver Assembly
    VDA     Vapor Diffusion Apparatus
    VDA     Variable Data Area
    VDB     Verification Data Base
    Vdc     Volts, dc
    VDD     Verification Description Document
    VDD     Version Description Document
    VDI     Vendor Documentation Inventory
    VDI     Vertical Display Indicator
    VDS     Vehicle Dynamics Simulator
    VDT     Vehicle Data Table
    VDT     Video Display Terminal
    VDU     Visual Display Unit
    VE      Equivalent Velocity
    VE      Shuttle Engineering (KSC VBO Directorate)
    VE      Vehicle Engineering (KSC VBO Directorate)
    VECIB   Vehicle Engineering Change Implementation Board
    VECO    Vernier Engine Cutoff
    VECP	Value Engineering Change Proposal
    VEDS    Vehicle Emergency Detection System
    VEEGA	Venus-Earth-Earth Gravity Assist (Trajectory Used for Galileo to Jupiter)
    VEEI    Vehicle Electrical Engine Interface
    VEFCO   Vertical Functional Checkout
    VEH     Vehicle
    VEH ID  Vehicle Identification
    VEI     Vehicle End Item
    VEL     Velocity
    VER     Verify
    VERIF   Verification
    VERLORT Very Long Range Tracking Radar
    VERN    Vernier
    VERT    Vertical
    VES     Vacuum Exhaust System
    VF      Vertical Flight
    VF      Video Frequency
    VFE     Vendor Furnished Equipment
    VFI     Verification Flight Instrumentation
    VFM     View Finder Monitor
    VFO     Variable Frequency Oscillator
    VFR     Visual Flight Rules
    VFT     Verification Flight Test
    VGIMU   Velocity To Be Gained as Related to IMU Orientation
    VGOR    Vandenberg Ground Operations Requirement
    VGOR    Vehicle Ground Operation Requirements
    VGP     Vehicle Ground Point
    VGT     Vehicle Ground Test
    VGVT    Vertical Ground Vibration Test
    VGX     Velocity To Be Gained (Body X-Axis)
    VGY     Velocity To Be Gained (Body Y-Axis)
    VGZ     Velocity To Be Gained (Body Z-Axis)
    VHAA    Very High Altitude Abort
    VHF     Very High Frequency
    VHF/AM  Very High Frequency Amplitude Modulator
    VHF/DF  Very High Frequency Direction Finder
    VHSIC   Very High Speed Integrated Circuit
    VI      Internal Velocity
    VIA     By Means of (By Way of)
    VIB     Vertical Integration Building
    VIB     Vibrate, Vibration
    VIC     Visitors Information Center
    VID     Video
    VIDD    Vertical Interval Data Detector
    VIL     Verified Item List
    VIP     Verification Integration Plan
    VIR     Visible Infrared Radar
    VIRD    Verification Implementation Requirements Document
    VIS     Verification Information System
    VIS     Visibility
    VIS     Visual
    VIS/UV  Visual/Ultraviolet
    VISC    Viscosity
    ViTS    Video Teleconferencing System
    VITT    Vehicle Integration Test Team
    VIU     Video Interface Unit
    VJ      Vacuum Jacketed
    VLA     Very Large Array
    VLBI    Very Long Baseline Interferometer
    VLF     Very Low Frequency
    VLPS    Vandenberg Launch Processing System
    VLR     Very Low Range
    VLS     Vandenberg Launch and Landing Site
    VLV     Value
    VLV     Valve
    VM      Virtual Memory
    VM      Voltmeter
    VMF     Vertical Maintenance Facility
    VMRR    Vendor Material Review Report
    VMS     Velocity Measuring System
    VO      Shuttle Operations (KSC Directorate)
    VO      Space Vehicle Operations (KSC Dir.)
    VO      Vehicle Operations
    VO      Velocity Initial
    VO      Voice
    VOIR    Venus Orbiter Imaging Radar
    VOL     Volume
    VOLT-A  Voltage Operating Limit Tests-A
    VOM     Volt-ohm-meter
    VOMD    VAFB Operations and Maintenance Documentation
    VOR     VHF Omnidirectional Radio Range
    VOR-DME VHF Omni Range-UHF Distance Measuring Equipment
    VORTAC  Variable Omni Range Tactical (VOR and TACAN)
    VORTAC  VHF Omni Range Tactical Air Navigation
    VOT     VHF Omni Test
    VOX     Voice Operated Transmitter (Transmission)
    VP      Shuttle Payloads (KSC VO Dir., see CO, CS, CV)
    VP      Vacuum Pump
    VP      Verification Polarization
    VP      Vertical Polarization
    VP      View Processor
    VP      Viewpoint
    VPC     Vapor Phase Compression
    VPF     Vertical Processing Facility
    VPHD    Vertical Payload Handling Device
    VPI     Valve Position Indicator
    VPK     Volts Peak
    VPM     Vehicle Project Manager
    VPP     Voluntary Protection Program
    VPPA    Variable Polarity Plasma Arc
    VR      Variable Reluctance
    VR      Velocity, Relative
    VR      Video Recorder
    VR      Voltage Regulator
    VR      Voltage Relay
    VRA     Velocity Referenced Attitude
    VRB     VHF Recovery Beacon
    VRCS    Vernier Reaction Control System
    VREL    Relative Velocity
    VRF     Vertical Removal Fixture
    VRL     Vertical Recovery Line
    VRL     Vertical Reference Line
    VRMS    Volts Root Mean Square
    VRNR    Vernier
    VRR     Verification Readiness Review
    VRS     Vacuum Resource System
    VRSD    Verification Requirements and Specification Document
    VS      Staging Velocity
    VS      Vestibular Sled (Spacelab D-1 Exp.)
    vs      Versus
    VSA     Variable Stability Aircraft
    VSA     Verification Site Approval
    VSB     Vestigial Side Band
    VSD     Vertical Situation Display
    VSI     Vertical Speed Indicator
    VSI     Video Simulation Interface
    VSO     Very Stable Oscillator
    VSTAG   Vandenberg Shuttle Turnaround Analysis Group
    VSWR    Visual Standing Wave Ratio
    VSWR    Voltage Standing Wave Ratio
    VT      STS Processing (KSC VO Dir.)
    VT      Vent
    VT/FT   Verification Test/Flight Test
    VTA     Vehicle Test Area
    VTA     Vertical Test Area
    VTE     Variable Thrust Engine
    VTF     Vertical Test Flight
    VTM     Vibration Test Module
    VTM     Virtual Team Meeting
    VTN     Verification Test Network
    VTP     Vehicle Test Plan
    VTP     Verification Test Plan
    VTP     Verification Test Program
    VTR     Verification Text Reports
    VTR     Videotape Recorder
    VTS     Vandenberg Tracking Station
    VTS     Vertical Test Site
    VTS     Vertical Test Stand
    VTS     Vertical Test System
    VTS     Video Test Set
    VTVM    Vacuum Tube Voltmeter
    VTX     Vertex
    VU      Vehicle Unit
    VU      Vehicle Utility
    VU      Volume Unit
    VUV     Vacuum Ultraviolet
    VV      Velocity Vector
    VV      Vent Valve
    VV      Vertical Velocity
    VVI     Vertical Velocity Indicator
    VWFC    Very Wide Field Camera
    VWG     Verification Working Group
    VX      Velocity Along the X-Axis
    VY      Velocity along the Y-Axis
    VZ      Velocity along the Z-Axis
    
    W
    
    W       Watt
    W       West
    W       Wide
    W       Window
    W&B     Weight and Balance
    W&C     Wire and Cable
    W-G     Water-Glycol
    W/      With
    W/B     Wideband
    W/E     Wing Elevon
    W/G     Water/Glycol
    W/h     Watt-Hour
    W/O     Without
    W/S     Work Station
    W/T     Wind Tunnel
    W/W     Weather
    W/W     Wheel Well
    W/W     Wrist Yaw
    W/WMS   Water/Waste Management System (Subsystem)
    WA      Wide Angle
    WA      Work Authorization
    WAD     Work Authorization Document
    WAD/SO  Work Authorization Document/Shop Order
    WAIS    Wide Area Information Server
    WAMDII  Wide Angle Michelson Doppler Imaging Inferometer
    WAN     Wide Area Network
    WAN/ISP Wide Area Network/Internet Service Provider
    WAN     Work Authorization Number
    WAR     Work Authorization Report
    WARN    Warning
    WAT     Web Action Time
    WAVE	WAD Authoring and Validation Environment
    WB      Waterboiler
    WB      Wet Bulb
    WB      Wide Band
    WBC     White Blood Cells
    WBDI    Wideband Data Interleaver
    WBDS    Wide Band Data Separator
    WBR     Work Bench Rack
    WBS     Work Breakdown Structure
    WBSC    Wide-Band Signal Conditioner
    WBT     Wide-Band Terminal
    WBTS    Wide-Band Transmission System
    WCCS    Window Contamination Control Number
    WCCU    Wireless Communications Control Unit
    WCDB    Work Control Data Base
    WCDDT   Wet Countdown Demonstration Test
    WCL     Water Coolant Line
    WCL     Water Coolant Loop
    WCLS    Water Coolant Loop System
    WCP     Wing Chord Plane
    WCS     Waste Collection System
    WCS     Work Control System
    WCS     Writable Control Storage
    WD      Width
    WD      Wired Discrete
    WD      Word
    WD      Work Days
    WEA     Weather
    WEFAX   Weather Facsimile
    WES     Water Electrolysis System
    WETA    Wireless Video System External Transceiver Assembly
    WETS    Weightless Environment Training System
    WF      Wide Field
    WF/PC   Wide Field/Planetary Camera
    WFF     Wallops Flight Facility
    WFPC    Wide Field Planetary Camera
    WG      Wage Grade      
    WG      Wave Guide
    WG      Wing
    WGS     Water Glycol Service Unit
    WHL     Wheel
    Whr     Watt-Hour
    WIB     When Interrupt Block
    WIF     Water Immersion Facility
    WIN     Irwin, Australia
    WINDS   Weather Information Network Display System
    WIP     Work In Progress
    WISP    Waves in Space Plasma
    WIX     Wait for Index
    WL      Wavelength
    WL      Werkstofflabor (Spacelab D-1 Exp.)
    WLE     Wing Leading Edge
    WM      Waste Management
    WMC     Waste Management Compartment
    WMS     Waste Management System
    WND     Wind
    WO      Work Order
    WOC     Work Order Control
    WOCE    World Ocean Circulation Experiment
    WONG    Weight on Nose Gear
    WORM    Write Once-Read Many Technology
    WOSE    Weather Office in Space Evaluation
    WOW     Weight on Wheels
    WOW     Worst on Worst
    WOWLON  Weight on Wheels Lock On
    WP      Way Point
    WP      Work Package
    WP      Working Pressure
    WP      Wrist Pitch
    WPAFB   Wright Patterson Air Force Base
    WPC     Watts Per Candle
    WPD     Work Package Description
    WPF     Work Process Flow
    WPG     Work Package Grouping
    WPI     Work Process Indicator
    WPI     Work Progress Indicator
    WPM     Words Per Minute
    WPMCP   Work Package Manpower and Cost Plan
    WPP     Water Pump Package
    WPP     Work Package Plan
    WPPS    Work Package Planning Sheet
    WPS     Words Per Second
    WR      Weather Radar
    WR      Wrist Roll
    WRG     Wiring
    WRL     Wing Reference Line
    WRM     Water Recovery and Management
    WRO     Work Release Order
    WS      Water Servicer
    WS      Wind Shield
    WS      Work Statement
    WSB     Water Spray Boiler
    WSC     Wide-Band Signal Conditioner
    WSCC    Work Station Control Center
    WSD     Wide-Band Data
    WSGS    White Sands Ground Station
    WSGT    White Sands Ground Terminal
    WSM     Waste Storage Module
    WSMC    Western Space and Missile Center
    WSMR    White Sands Missile Range
    WSO     Water Servicer Operator
    WSSH    White Sands Space Harbor
    WSTF    White Sands Test Facility
    WSU     Water Servicing Unit
    WSWR    Variable Standing Wave Ratio (Rate)
    WT      Watchdog Timer
    WT      Weight
    WT      Wire Ticket
    WTA     Wire Traceability and Accountability
    WTR     Water
    WTR     Western Test Range
    WTR SYS Water System
    WTSC    Wet Tantalum Slug Capacitor
    WTT     Wind Tunnel Test
    WUC     Work Unit Code
    WUCF    Work Unit Code File
    WUPPE   Wisconsin Ultraviolet Photo Polarimeter Experiment
    WUSCI   Western Union Space Communications, Inc.
    WVCF    Western Vehicle Checkout Facility
    WW      Water Waste
    WW      Wire Wrap
    WWMS    Waste Water Management System
    WWW     World Wide Web
    WX      Weather
    WY      Wrist Yaw
    
    X
    
    X       Times (by, trans-)
    XL      X-Axis of Spacelab
    XO      X-Axis of Orbiter
    XP      X-Axis of Payload
    XS      X-Axis of Solid Rocket Booster
    XT      X-Axis of External Tank
    XCVR    Transceiver
    XDA     X-Ray Detector Assembly
    XDCR    Transducer
    XFD     Crossfeed
    XFER    Transfer
    XLTN    Translation
    XMM     X-Ray Multimission
    XMT     Transmit
    XMTR    Transmitter
    XNS     Xerox Network Systems
    XO      Orbiter Structural Body Reference, X-Axis
    XP      Payload Structural Body Reference, X-Axis
    XPNDR   Transponder
    XRCF    X-Ray Calibration Facility
    XRD     X-Ray Diffraction
    XRP     X-Ray Polychromator
    XRS     X-Ray Spectrometer
    XRT     X-Ray Telescope
    XSST    X-Ray Spectrometer/Spectrograph Telescope
    XTA     X-Ray Telescope Assembly
    XTAL    Crystal
    XTE     X-Ray Timing Explorer
    XUV     Extreme Ultraviolet (also EUV)
    
    Y
    
    Y       Horizontal Axis-Width of Vehicle
    Y       Lateral Acceleration
    Y       Out-of-Plane Position
    Y       Out-of-Plane Velocity
    Y       Y-Axis
    Y       Y-Axis, Horizontal-Width of Vehicle/Structure
    Y       Y-Axis Rate of Change
    Y       Yaw
    YL      Y-Axis of Spacelab
    YO      Y-Axis of Orbiter
    YP      Y-Axis of Payload
    YS	Y-Axis of Solid Rocket Booster
    YT	Y-Axis of External Tank
    YAR     Yarragadee (STDN Site)
    yd      Yard
    YP      Yield Pointer
    yr      Year
    YS      Yield Strength
    YSC     Yearly Spares Cost
    YST     Yearly Spares Cost
    YT      Station Identification Symbol
    YV      Deputy for Space Launch Systems
    YVC     Directorate of Configuration and Information Management
    YVCB    Configuration/Data Management Division
    YVGF    Financial Management Division (SD)
    YVGR    Requirements and Analysis Division (SD)
    YVV     Directorate of Launch Base Operations
    YVV-1   Program Safety Office (SD)
    YVVE    Engineering Division
    YVVI    Inertial Upper Stage
    YVVL    Integrated Logistics Support Division (SD)
    YVVO    Operations Division
    YVVS    DOD Mission Support Division, JSC (SD)
    
    Z
    
    Z       Impedance
    Z       Normal Acceleration (Load Factor)
    Z       Z-Axis Direction
    Z       Z-Axis Rate of Change
    Z       Zone
    Z       Zulu (Greenwich Mean Time--GMT)
    ZL      Z-Axis of Spacelab
    ZO      Z-Axis of Orbiter
    ZP      Z-Axis of Payload
    ZS	Z-Axis of Solid Rocket Booster
    ZT	Z-Axis of External Tank
    ZBB     Zero Base Budget
    ZC      Zero Calibration
    ZCG     Impedance Cargiogram
    ZGT     Zero Gravity Trainer
    ZI      Zone of Interior (Continental USA)
    ZIF     Zero Insertion Force
    ZLV     Z Local Vertical (Payload Bay Toward Earth)
    ZO      Station Identification Symbol, Orbiter X-Axis
    ZOE     Zone of Exclusion
    ZOP     Zero Operational Ajont Code
    ZPN     Impedance Cardiogram
    ZPN     Impedance Pneumogram
    ZrO2    Zirconium Oxide
    ZSI     Z Solar Inertial (Payload Bay Facing Away From Sun)
    

    Information Center

Page Last Revised Page & Curator Information
February 20, 2009
Curator: Kay Grinter (Kay.Grinter-1@ksc.nasa.gov)
NASA Official: Jeanne Rybe  (Jeanne.Ryba@ksc.nasa.gov)
Web Development: JBOSC Web Development Team
A service of the NASA/Kennedy Space Center External Relations Directorate:
Lisa A. Malone, Director