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MARS OBSERVER PRESS KIT SEPTEMBER 1992 PUBLIC AFFAIRS CONTACTS NASA HEADQUARTERS, WASHINGTON, D.C. Office of Space Science and Applications Paula Cleggett-Haleim Donald L. Savage Office of Communications Dwayne C. Brown JET PROPULSION LABORATORY, PASADENA, CALIF. Robert J. MacMillan Diane Ainsworth KENNEDY SPACE CENTER, FLA. Dick Young Karl Kristofferson George H. Diller MARSHALL SPACE FLIGHT CENTER, HUNTSVILLE, ALA. Dom Amatore Jerry Berg LEWIS RESEARCH CENTER, CLEVELAND Marilyn S. Edwards Mary Ann Peto CONTENTS General Release 1 Mars Observer Science Objectives 6 Mission Design 7 Spacecraft Science Instruments 9 Mapping Cycle 17 The Spacecraft System 18 Spacecraft Description 19 Titan III Launch Vehicle 20 Titan III Facts 21 Transfer Orbit Stage 23 Launch Vehicle and Payload Processing 27 Launch Countdown and Flight Control 28 Countdown Milestone Events 29 Mars Observer/Titan III/TOS Tracking Support 30 Salient Facts on Speed and Distance 31 Science Operations 32 Mars Observer Investigators 33 Interdisciplinary Scientists 36 Mars Observer Management 37 MARS OBSERVER READY TO TAKE THE NEXT STEP IN MARS EXPLORATION RELEASE: 92-142 NASA will continue the exploration of Mars -- started by the Mariner IV spacecraft 28 years ago -- when Mars Observer is launched in September. The last U.S. spacecraft to visit Mars was Viking 2 in 1976. "Mars Observer will examine Mars much like Earth satellites now map our weather and resources," said Dr. Wesley Huntress, Director of NASA's Solar System Exploration Division, Washington, D.C. "It will give us a vast amount of geological and atmospheric information covering a full Martian year. At last we will know what Mars is actually like in all seasons, from the ground up, pole to pole. "In the mid 1960s, the Mariner flybys resulted in the historic first pictures of the cratered surface of Mars," Huntress continued. "Then, the Viking landers looked for signs of life at two landing sites. The Viking orbiters also made global maps which gave us a good picture primarily of surface features. Now, the Mars Observer mission marks the next phase in planetary exploration." "Mars Observer will tell us far more about Mars than we've learned from all previous missions to date," said David Evans, Project Manager, NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif. "We want to put together a global portrait of Mars as it exists today and, with that information, we can begin to understand the history of Mars. "By studying the evolution of Mars, as well as Venus', we hope to develop a better understanding as to what is now happening to planet Earth," Evans said. "As we look even further into the future, this survey will be used to guide future expeditions to Mars. The first humans to set foot on that planet will certainly use Mars Observer maps and rely on its geologic and climatic data," Evans said. Launch and Cruise to Mars Mars Observer is scheduled for launch aboard a Titan III rocket in late September from Cape Canaveral Air Force Station, Fla. The beginning of the launch opportunity is Sept. 16, 1992. The launch window opens at 1:02 p.m. EDT and closes at 3:05 p.m. EDT. The daily launch window will vary slightly on subsequent days. The 28-day launch opportunity extends through Oct. 13, 1992. Mars Observer will be lofted into Earth orbit aboard a Titan III launch vehicle. After separation from the Titan, an upper stage vehicle -- the Transfer Orbit Stage (TOS) -- will fire to free the spacecraft from Earth's gravity and send it on to Mars. "During its 11-month transit from Earth to Mars, known as the cruise phase, Mars Observer will deploy four of its six solar panels to begin drawing solar power," said George Pace, Spacecraft Manager at JPL. "The dish-shaped, high-gain antenna will be deployed and the Magnetometer and Electron Reflectometer (MAG/ER) and the Gamma Ray Spectrometer (GRS) will be partially deployed," Pace said. "Four trajectory correction maneuvers are planned during the cruise phase to guide the spacecraft to its destination." On Aug. 19, 1993, Mars Observer will arrive in the vicinity of Mars. As it approaches the planet, the spacecraft will fire onboard rocket engines to slow its speed and allow the gravity of Mars to capture it in orbit around the planet. Mars Observer will first enter a highly elliptical orbit. Then, over a period of 4 months, onboard rocket thrusters will gradually move the spacecraft into a nearly circular orbit inclined 93 degrees to the planet's equator at 204 nautical miles (378 kilometers) above the Martian surface. In this orbit, the spacecraft will fly near the Martian poles. Global Mapping Mission and Science Operations Mars Observer will provide scientists with an orbital platform from which the entire Martian surface and atmosphere will be examined and mapped. The measurements will be collected daily from the low-altitude polar orbit, over the course of 1 complete Martian year -- the equivalent of 687 Earth days. "The scientific payload consists of seven science instruments to examine Mars from the ionosphere -- an envelope of charged particles that surrounds Mars -- through the atmosphere and to the surface," said Dr. Arden Albee, Project Scientist at the California Institute of Technology. "The science instruments will provide teams of experimenters with daily global maps of the planet," Albee said. "Mars Observer's camera (MC) will resolve objects far smaller than was previously possible -- down to about 33 feet (10 meters) in diameter." Scientists will control their spaceborne experiments from their home institutions through a computer network linking them to the Mars Observer operations center at JPL. They can access data from their experiments daily using special workstations and electronic communications links and distribute results to other mission science teams. International Participation Near the end of its prime mission in the fall of 1995, Mars Observer may be joined by the Russian "Mars '94" spacecraft. Current plans call for the Russian spacecraft to deploy penetrators as well as small surface stations. Mars Observer's Mars Balloon Relay (MBR) radio-receiver equipment, supplied by the Centre National d'Etudes Spatiales (CNES) in France, is designed to relay data from the penetrators and surface stations to Earth. The Mars Observer mission also includes scientists from three countries besides the United States on its seven investigation teams, both as team members and as co- investigators. In addition, four foreign participating scientists will join the teams in October 1992. Also in October, 11 participating scientists from Russia will be added to the teams as part of the continuing formal U.S. - Russian cooperation in planetary exploration. Program and Mission Management The Mars Observer spacecraft was built under contract to NASA and JPL by the Astro-Space Division of General Electric, Princeton, N.J. NASA's Lewis Research Center in Cleveland, Ohio, managed the commercial launch services contract with Martin Marietta Commercial Titan, Inc., Denver, which supplied the Titan III launch vehicle. The Transfer Orbit Stage (TOS) was built by Martin Marietta under contract to Orbital Sciences Corp., Vienna, Va. The TOS project was managed by NASA's Marshall Space Flight Center, Huntsville, Ala. Launch Complex 40 at the Cape Canaveral Air Force Station was completely refurbished for the launch by Martin Marietta and the Bechtel Corporation under contract to the U.S. Air Force. NASA's Deep Space Network (DSN) will support the launch, mission operations and tracking of the spacecraft throughout its primary mission. Tracking and data retrieval through the DSN are managed by JPL for NASA's Office of Space Communications, Washington, D.C. The Mars Observer Project Manager is David D. Evans of JPL. Dr. Arden Albee of the California Institute of Technology is the Project Scientist. Dr. William L. Piotrowski of NASA Headquarters is the Mars Observer Program Manager and Dr. Bevan French is the Program Scientist. JPL manages the mission for the Solar System Exploration Division of NASA's Office of Space Science and Applications at NASA Headquarters, Washington, D.C. - end of general release - MARS OBSERVER SCIENCE OBJECTIVES The Mars Observer mission will study the geology, geophysics and climate of Mars. The primary objectives are to: % identify and map surface elements and minerals; % measure the surface topography and features; % define globally the gravitational field; % determine the nature of the magnetic field; % determine the distribution, abundance, sources and destinations of volatile material (carbon dioxide, water) and dust over a seasonal cycle; and % explore the structure and aspects of the circulation of the atmosphere. The mission will provide scientists with a global portrait of Mars as it exists today using instruments similar to those now used to study the Earth. The seven instruments have been selected so that observations from one provide a complimentary approach to the mission objectives. For example, the composition of surface minerals will be addressed by both the Gamma Ray Spectrometer (chemical composition) and the Thermal Emission Spectrometer (mineral composition). The interdisciplinary investigations of the Mars Observer mission also will combine data from more than one instrument to explore questions that cross boundaries between scientific disciplines and individual investigations. The six interdisciplinary investigations are: % atmospheres/climatology; % data management/archiving and surface weathering processes; % geosciences; % polar atmospheric sciences; % surface-atmosphere interactions; and % surface properties and morphology. The mission will provide a major increase in available scientific data about Mars. During its 687-day mapping mission, Mars Observer will return about 120 megabytes of data per day, for a total of about 80 - 90 gigabytes (about 600 billion bits of information). This amounts to more scientific information than has been returned by all previous planetary missions, whether to Mars or elsewhere, not including the current Magellan mission. Mission Design Following launch and insertion into a trans-Martian trajectory by TOS, the spacecraft will perform four trajectory correction maneuvers (TCM) to correct and adjust the trajectory. TCM-1, scheduled for L+15 days (Oct. 1, 1992), will correct any errors from injection. Following TCM-2, both the GRS and the MAG/ER will be activated to collect data on the space environment. On Jan. 20, 1993, the MOC will be powered on to take two narrow angle images as a check-out. The Mars orbit insertion phase is the transition from the interplanetary cruise phase to the mapping orbit. Since direct transition into the mapping orbit would require undesirable out-of-plane maneuvers, a series of seven orbit insertion maneuvers will be performed to bring the spacecraft into the proper orbit for mapping. During these maneuvers there will be limited scientific activity. The polar orbit chosen for the Mars Observer mission is low enough to allow close-range study of Mars, but high enough so that the atmosphere does not drag excessively on the spacecraft. The orbit also is sun-synchronous, meaning that the spacecraft will pass over Mars' equator at the same local time during each orbit -- about 2 p.m. on the day side and about 2 a.m. on the night side. This orbit is essential for a number of measurements, as it helps distinguish daily atmospheric variations from seasonal variations. During the mission's mapping cycle, which begins in earnest on Jan. 13, 1994, data reception from the spacecraft and command updates to the spacecraft and individual science instruments will be conducted on a daily basis. Once the primary task is completed, the Mars Observer mission may be extended -- if the spacecraft and instruments are still in good condition and if there is enough fuel to control the spacecraft's altitude and orientation. SPACECRAFT SCIENCE INSTRUMENTS Collectively, Mars Observer's seven scientific instruments will cover much of the electromagnetic spectrum and form a complementary array. Each instrument produces sets of data that contribute to a wide variety of scientific investigations. Gamma Ray Spectrometer (GRS) The Gamma Ray Spectrometer will characterize the chemical elements present on and near the surface of Mars with a surface resolution of a few hundred kilometers. The data will be obtained by measuring the intensities of gamma rays that emerge from the Martian surface. These high-energy rays are created from the natural decay of radioactive elements or can be produced by the interaction of cosmic rays with the atmosphere and surface. By observing the number and energy of these gamma rays, it is possible to determine the chemical composition of the surface, element by element. The GRS also can measure the presence of any volatiles, such as water and carbon dioxide, as "permafrost" in the surface materials and the varying thickness of the polar caps. Mars Observer Camera (MOC) The Mars Observer Camera system will photograph the Martian surface with the highest resolution ever accomplished by an orbiting civilian spacecraft. Resolution is a measure of the smallest object that can be seen in an image. Low-resolution global images of Mars -- a daily 'weather map' -- also will be acquired each day using two wide-angle cameras operated at 4.7-mile (7.5-kilometer) resolution per picture element (pixel). These same cameras will acquire moderate-resolution photographs at 787 feet (240 meters) per pixel. A separate camera will acquire very-high-resolution images at 4.6 feet (1.4 meters) per pixel for features of special interest. Each of these camera systems uses a line array of several thousand detectors and the motion of the spacecraft to create the images. The low-resolution camera system will capture global views of the Martian atmosphere and surface so that scientists may study the Martian weather and related surface changes on a daily basis. Moderate-resolution images will monitor changes in the surface and atmosphere over hours, days, weeks, months and years. The high-resolution camera system will be used selectively because of the high data volume required for each image. Thermal Emission Spectrometer (TES) The Thermal Emission Spectrometer will measure infrared thermal radiation emitted from the Martian atmosphere and surface. The thermal properties of Martian surface materials and their mineral content may be determined from these measurements. When viewing the surface beneath the spacecraft, the spectrometer has six fields of view, each covering an area of 1.9 by 1.9 miles (3 by 3 kilometers). The spectrometer, a Michelson interferometer, will determine the composition of surface rocks and ice and map their distribution on the Martian surface. Other capabilities of the instrument will investigate the advance and retreat of the polar ice caps, as well as the amount of radiation absorbed, reflected and emitted by these caps. The distribution of atmospheric dust and clouds also will be examined over the 4 seasons of the Martian year. Pressure Modulator Infrared Radiometer (PMIRR) This radiometer will measure the vertical profile of the tenuous Martian atmosphere by detecting infrared radiation from the atmosphere itself. For the most part, the instrument will measure infrared radiation from the limb, or above the horizon, to provide high-resolution (3-mi./5-km.) vertical profiles through the atmosphere. The measurements will be used to derive atmospheric pressure and determine temperature, water vapor and dust profiles from near the surface to as high as 50 miles above the surface. Using these measurements, global models of the Martian atmosphere, including seasonal changes that affect the polar caps, can be constructed and verified. Mars Observer Laser Altimeter (MOLA) The Mars Observer Laser Altimeter uses a very short pulse of laser light to measure the distance from the spacecraft to the surface with a precision of several meters. These measurements of the topography of Mars will provide a better understanding of the relationship among the Martian gravity field, the surface topography and the forces responsible for shaping the large-scale features of the planet's crust. Radio Science The Radio Science investigation will use the spacecraft's telecommunication system and the giant parabolic (dish-shaped) antennas of NASA's Deep Space Network to probe the Martian gravity field and atmosphere. These measurements will help scientists determine the structure, pressure and temperature of the Martian atmosphere. Each time the spacecraft passes behind the planet or reappears on the opposite side, its radio beam will pass through the Martian atmosphere briefly on its way to Earth. The way in which the radio waves are bent and slowed will provide data about the atmospheric structure at a much higher vertical resolution than any other Mars Observer experiment. During that part of the orbit when the spacecraft is in view of Earth, precise measurements of the frequency of the signal received at the ground tracking stations will be made to determine the velocity change (using the Doppler effect) of the spacecraft in its orbit around Mars. These Doppler measurements, along with measurements of the distance from the Earth to the spacecraft, will be used to navigate the spacecraft and to study the planet's gravitational field. Gravitational field models of Mars will be used along with topographic measurements to study the Martian crust and upper mantle. By the end of the mission, as a result of the low altitude of the orbit and the uniform coverage of Mars Observer, scientists will have obtained unprecedented global knowledge of the Martian gravitational field. Magnetometer and Electron Reflectometer (MAG/ER) Mars is now the only planet in the solar system, aside from Pluto, for which a planetary magnetic field has not yet been detected. In addition to searching for a Martian planetary magnetic field, this instrument also will scan the surface material for remnants of a magnetic field that may have existed in the distant past. The magnetic field generated by the interaction of the solar wind with the upper atmosphere of Mars also will be studied. Mars Balloon Relay (MBR) The spacecraft carries a radio system supplied by the French Centre National d'Etudes Spatiales (CNES) to support the Russian Mars 94 mission. The Mars 94 spacecraft consists of an orbiter, to be launched in October 1994, which will deploy penetrators and small stations designed to land and operate on the Martian surface. The landers and penetrators will carry instruments to directly sample both the atmosphere and the surface. The landers and penetrators will send data to the Mars 94 orbiter, or to Mars Observer as a back up, for subsequent relay to Earth. Both the landers and penetrators are designed to operate for several years. The MBR equipment consists of a transmitter/receiver that will periodically receive and relay scientific and engineering data to Earth. If it is still operating on an extended mission, Mars Observer also may support the Russian Mars '96 mission, which is planning to release a balloon into the Martian atmosphere and possibly deploy landed stations or rover vehicles which can move about on the surface under their own power, operated either by remote control from Earth or autonomously under computer control. Following a launch during the 1996 window, the Mars '96 spacecraft would reach Mars in 1997. MAPPING CYCLE In its near-circular mapping orbit, the Mars Observer spacecraft will rotate once per orbit to keep the instruments pointed at the planet. This will allow all instruments to view the planet continuously and uniformly during the entire Martian year. The spacecraft, instruments and mission were designed so that sufficient resources, especially power and data rate, are available to power all instruments as they collect data simultaneously and continuously on both the day and night sides of the planet. The camera system takes photos only on the day side and will acquire additional images every 3 days during real-time radio transmissions to the Deep Space Network. The rotation and orientation of the spacecraft are controlled by horizon sensors, a star sensor, gyroscopes and reaction wheels, as is common on Earth-orbiting satellites. The horizon sensors, adapted from a terrestrial design, continuously locate the horizon, providing control signals to the spacecraft. The star sensor will be used for attitude control during the 11-month cruise and as a backup to the horizon sensors during the mapping orbit. Once during each 118-minute orbit, the spacecraft will enter the shadow of Mars and rely on battery power for about 40 minutes. The battery is charged by the spacecraft's large solar panel, which generates more than a kilowatt of power when it is in the sunlight. Control of the spacecraft and instruments is accomplished through the use of onboard microprocessors and solid-state memories. Scientific and engineering data are stored on tape recorders for daily playback to Earth. Additional data operations will allow information to be returned in real-time from selected instruments whenever Earth is in view. The lifetime of the spacecraft will most likely be determined by the supply of attitude-control fuel and the condition of the batteries. THE SPACECRAFT SYSTEM The Mars Observer spacecraft uses, where possible, existing Earth-orbiting satellite component designs. The craft's main body is shaped like a box and is about 3.25 feet (1.1 meters) high, 7.0 feet (2.2 meters) wide, and 5.0 feet (1.6 meters) deep. Mars Observer was built by General Electric's Astro-Space Division in Princeton, N.J. With its fuel, the spacecraft and its science instruments weigh about 5,672 pounds (2,573 kilograms). The spacecraft has a 3-year design lifetime and is equipped with one large solar array, consisting of six 6 x 7.2 x 0.3-foot (183 x 219 x 9.1-centimeter) solar panels. At launch, the spacecraft's main communication antenna, instrument booms and solar array will be folded close to the spacecraft. During the cruise phase these structures will be partially extended. The two 20-foot (6-meter) instrument booms carry two of Mars Observer's seven scientific instruments, the Magnetometer and Electron Reflectometer and the Gamma Ray Spectrometer. After the Mars Observer spacecraft reaches its mapping orbit at Mars, the solar array and instrument booms will be fully unfolded. The main communication antenna -- a 4.75- foot (1.45-meter) diameter parabolic antenna -- will be raised on a 20-foot (6-meter) boom and rotated to have a clear view of Earth. The spacecraft then will power its instruments to begin conducting the mission experiments. Spacecraft Statistics GENERAL Design Life 3 years Mapping Orbit Mars polar, nearly circular Altitude Above Mars 400 km (242 miles), nominal Key Features Seven science instruments (two mounted on 6-m booms) Bi- and monopropulsion systems Three-axis control system (highly stabilized) Semiautonomous operation (stores up to 2000 commands) Reliability Redundancy used to avoid single-point failures Payload Weight 156 kg (343 lb) Total Weight 2573 kg (5672 lb) Size (launch configuration): Length 1.6 m (5.0 ft) Width 2.2 m (7.0 ft) Height 1.1 m (3.25 ft) COMMUNICATIONS Command Rate 12.5 commands/s (max) Uplink Data Rate 500 bits/s (max) Downlink Data Rate 85.3 kbits/s (max) Antennas 1.45-m-diam. high-gain parabolic articulating (on 6-m boom) Three low-gain Downlink RF Power 44 watts Tape Recorders 1.38 x 109-bit capacity PROPULSION Bipropellant System Monomethyl hydrazine and nitrogen tetroxide Monopropellant System Hydrazine Thrusters (24 total) (4) 490 N (4) 22 N (8) 4.5 N (orbit trim) (8) 0.9 N (momentum unloading and steering) Total Propellant Weight 1346 kg (2961 lb) ATTITUDE AND ARTICULATION CONTROL Pointing Accuracy Control: 10 mrad Knowledge: 3 mrad Pointing Stability 1 mrad (for 0.5 s) 3 mrad (for 12 s) ELECTRICAL POWER Solar Array 6 panels, each 183 ~ 219 cm Array Output Power 1130 watts Batteries 42-amp-hr NiCd (2) Electronics Bus voltage regulation Definitions: mrad = milliradian (E 0.057!) N = newton (E 0.225 lb force) TITAN III LAUNCH VEHICLE Launch Services Contract The NASA Lewis Research Center, Cleveland, is responsible for the management of the Titan III launch services contract with Martin Marietta Corp., Denver, for the launch of the Mars Observer. Lewis is responsible for the management, technical oversight and integration of the payload with the Titan launch system which includes the analytical, physical, environmental and operational integration activities. Lewis, along with the Jet Propulsion Laboratory and the Marshall Space Flight Center, is responsible for integrated trajectory design, including development of an integrated sequence of events from lift-off through planetary spacecraft separation from the upper stage. Launch Vehicle The Titan III can place payloads in excess of 31,000 pounds into low-Earth orbit and up to 11,000 pounds into a geosynchronous transfer orbit. The Titan III is a member of the Titan launch vehicle series that has been in use by the U.S. Air Force and NASA for more than 20 years, including use in the Gemini program. The Titan III also was used for NASA's Voyager missions as well as the two Viking missions, the last U.S. spacecraft to Mars. The core vehicle consists of two liquid-propellant booster stages that are the central propulsion element. Twin 10.2-foot diameter solid-propellant rocket motors (SRMs) are attached to the core vehicle and provide thrust during initial lift-off and boost phase. TITAN III FACTS SOLID ROCKET MOTORS (2) Length: 90.4 feet (27.6 meters) Diameter: 10.2 feet (3.1 meters) Motor Thrust: 1.4 million pounds (6,200 kiloNewtons) per motor Weight: 552,000 pounds (250,387 kilograms) per motor Propellants: UTP-30001B solid Contractor: United Technologies FIRST STAGE Length: 78.6 feet (24 meters) Diameter: 10 feet (3 meters) Engine Thrust: 548,000 pounds (2,43 kiloNewtons) Propellants: Aerozine 50, nitrogen tetroxide Contractor: Martin Marietta SECOND STAGE Length: 32.7 feet (10 meters) Diameter: 10 feet (3 meters) Engine Thrust: 105,000 pounds (467 kiloNewtons) Propellants: Aerozine 50, nitrogen tetroxide Contractor: Martin Marietta PAYLOAD FAIRING Diameter: 13.1 feet (4 meters) Overall Length: 34.2 feet (10.4 meters) Contractor: Contraves AG EXTENSION MODULE Single Payload Mission Length: 4.4 feet (1.34 meters) Diameter: 13.1 feet (4 meters) Contractor: Dornier GmbH LAUNCH SITE Launch Complex 40 and associated processing facilities at Cape Canaveral Air Force Station, Fla. COMMERCIAL TITAN United Technologies, Chemical Systems CONTRACTOR TEAM Division (solid rocket motors) Aerojet TechSystems Co. (liquid- propellant engines) General Motors' Delco Systems Contraves AG (payload fairing) Dornier GmbH (extension module) Transfer Orbit Stage A new upper stage vehicle, known as the Transfer Orbit Stage (TOS), will make its maiden flight during the Mars Observer mission. Following launch aboard the Titan III rocket, the TOS will propel the spacecraft on its 11-month interplanetary journey to Mars. TOS is a single-stage, solid-propellant upper stage vehicle used to propel a spacecraft from low-Earth orbit toward its ultimate destination. It is a versatile addition to NASA's inventory of upper stage vehicles, designed to retain reliability and reduce cost. Under the terms of a 1983 agreement with Orbital Sciences Corp., Fairfax, Va., NASA provided technical assistance during the development of TOS. NASA's TOS Project Office at the Marshall Space Flight Center, Huntsville, Ala., ensured vehicle performance, reliability and compliance with launch vehicle and spacecraft integration and flight-safety requirements. TOS Vehicle Description The Mars Observer TOS weighs 24,000 pounds, with a diameter of approximately 11.5 feet and length of just under 11 feet. The TOS system consists of flight vehicle hardware and software, as well as associated ground support equipment. This vehicle uses a United Technologies Chemical Systems Division ORBUS-21 solid rocket motor main propulsion system, a Honeywell, Inc., laser inertial navigation system, a hydrazine reaction control system, and sequencing and power subsystems. It has an inertial guidance and three-axis control system, allowing the spacecraft to roll, pitch and yaw. The propulsion systems for TOS are a main propulsion system and an attitude control system. The ORBUS-21 solid rocket motor, the main propulsion for TOS, has a gimbaled, or pivoting, nozzle to provide pitch and yaw control during motor firing. For the Mars Observer mission, TOS will be loaded with approximately 22,000 pounds of the solid propellant HTPB (hydroxyl terminated poly-butadiene). The motor can be loaded with a reduced propellant quantity -- as low as 50 percent of the full load -- to handle a wide range of mission payload and energy requirements. Motor ignition is provided by a pyrotechnically initiated solid propellant ignitor system. The vehicle's hydrazine-powered reaction control system provides for attitude control of the TOS and TOS/spacecraft combination during solid rocket motor firing and during periods when the large solid rocket motor is not firing. The system uses 12 attitude control system thrusters, or small maneuvering rockets. TOS avionics hardware and software perform guidance functions, manage the in-flight data, initiate the sequence of events, determine the distance traveled and send back engineering data on rocket systems operation during the boosting phase of the mission. The laser inertial navigation system is the heart of the package which provides the required guidance, navigation and control functions. The First TOS Mission Fifteen minutes after liftoff, the Titan III will separate from the TOS and the Mars Observer spacecraft. For about the next 20 minutes, TOS will provide attitude control of the movements of the spacecraft. It will perform the necessary calculations and generate the proper commands, including rotating the spacecraft for thermal control, to ensure the spacecraft is placed into the proper position for rocket motor ignition which will propel Mars Observer on its interplanetary course. Approximately 20 minutes after separation from the Titan III, the TOS solid rocket motor will fire for its 150-second burn. The powered-flight period of TOS operation will last approximately 2.5 minutes, during which the spacecraft/TOS combination will reach a speed of 25,575 miles per hour. Then, having done its job, it will separate from the Mars Observer. Launch Vehicle and Payload Processing On June 19, the Mars Observer spacecraft arrived at the Kennedy Space Center (KSC) in an over-the-road environmentally controlled payload transporter known as PETS, the Payload Environmental Transportation System. It was taken to Hangar AO located on Cape Canaveral Air Force Station to begin checkout. Spacecraft subsystem testing was performed, the integrity of the onboard propulsion system was checked and compatibility with the world-wide Deep Space Network tracking stations was verified. On July 9, Mars Observer was again moved by the PETS from Hangar AO to the Payload Hazardous Servicing Facility (PHSF) on KSC. There, final electrical testing was completed, the spacecraft was fueled with its flight load of hydrazine propellant and a weight and balance measurement was taken. On Aug. 3, it was mated to the upper stage vehicle, the Transfer Orbit Stage (TOS). The TOS arrived at the PHSF on Jan. 10 to begin processing and electrical testing which was completed in late June. The Titan III rocket arrived from Martin Marietta in Denver by C-5 aircraft on Feb. 28 and was taken to the Vertical Integration Building (VIB) to begin build up. The first and second stage engine installation activity began in mid-March, and on March 26 the vehicle was erected on the launch platform. Meanwhile, in the near-by Solid Rocket Motor Assembly Building (SMAB) the build-up of the solid rocket boosters also began in mid-March and was completed on May 18. On June 24, the Titan core vehicle was moved from the VIB to the SMAB for mating to the twin solid rocket booster stack. The rollout of the complete Titan III vehicle to Launch Complex 40 occurred on June 2. The integrated Mars Observer/Transfer Orbit Stage payload was encapsulated in the Titan III nose fairing at the PHSF on Aug. 19. It was transported to Launch Complex 40 on Cape Canaveral Air Force Station on Aug. 21 and hoisted into the clean room of the gantry-like mobile service tower and mated to the rocket. On Aug. 25 a routine inspection of the payload revealed particulate contamination on the surface of the spacecraft. The payload was demated and returned to the PHSF for cleaning on Aug. 29. On Sept. 4 the payload was scheduled to be mated to the launch vehicle. A countdown dress rehearsal is scheduled for Sept. 17, with launch scheduled for Sept. 25. LAUNCH COUNTDOWN AND FLIGHT CONTROL The countdown for the launch of the Titan III with the Mars Observer spacecraft will be conducted from a combination of NASA and U.S. Air Force Facilities on Cape Canaveral Air Force Station. The primary facility from which management decisions will be made is the Mission Director's Center (MDC) located in Hangar AE. This is the nerve center of expendable vehicle launch operations. From here and the adjacent Launch Vehicle Data Center (LVDC), the health of the launch vehicle and the Mars Observer spacecraft will be monitored before launch. Actual control of the Titan III rocket before launch, and from where the terminal launch countdown events are initiated, will be from the Vertical Integration Building (VIB) in the Titan complex. Control of the upper stage before launch, the Transfer Orbit Stage, will be from the TOS Payload Operations Control Center (POCC) on Kennedy Space Center. Also in Hangar AE is where NASA's central telemetry facility, or telemetry lab, is located. During powered flight performance data from the Titan III, the TOS and Mars Observer will arrive here. The data will be recorded and displayed, then forwarded to flight control areas. Among those areas are the MDC and LVDC in Hangar AE, the Mars Observer Mission Operations Center in nearby Hangar AO and the TOS POCC. All events which occur during powered flight will be monitored and displayed in the Mission Director's Center. Vehicle flight data will also be displayed in the LVDC and the VIB. After payload separation, primary monitoring will be from the Mars Observer Mission Operations Center in Hangar AO, the TOS POCC at KSC and from Jet Propulsion Laboratory in Pasadena. Countdown Milestone Events: T-Time (minutes:seconds) Call to stations T-420 Power-up TOS T-410 Titan Inertial Guidance System alignment complete T-400 Range Safety holdfire checks T-345 Load Mars Observer star catalog T-255 Begin Titan III final checks T-230 Titan III checks complete T-150 Poll launch team for mobile service tower rollback T-100 Mobile service tower in launch position T-30 Enter planned 50-minute built-in hold T-30 Resume countdown T-25 Mars Observer to flight mode T-10 Enter 10-minute built in hold/poll launch team T-10 Resume countdown T-07 Poll launch team for final status checks T-05 Resume countdown T-04 Mars Observer to internal power T-2:30 Range Safety clear to launch T-2:00 Start data recorders T-1:55 Arm firing chain relay T-1:05 Start launch sequence T-1:03 Enter terminal count T-0:50 TOS to inertial guidance T-0:37 TOS to internal power T-0:32 Titan III to internal power T-0:16 Arm Range Safety Command Destruct system T-0:02 Titan to inertial guidance/arm booster igniters 0.0 Sold rocket booster ignition 0.2 Liftoff 00:54 Maximum dynamic pressure 01:48 Titan core vehicle ignition 01:56 Solid rocket booster jettision 03:51 Jettision payload fairing 04:28 Stage 2 ignition 04:29 Stage 1 separation 08:06 Stage 2 cutoff 15:00 Vehicle/payload separation 31:20 TOS ignition 33:56 TOS burnout 53:31 TOS/Mars Observer separation 68:30 Deploy solar array for cruise 71:40 Deploy high gain antenna 75:26 Deploy Gamma Ray Spectrometer boom for cruise 76:00 Deploy Magnatometer boom for cruise 76:10 Turn on attitude control system 80:42 Turn on low gain transmitter MARS OBSERVER/TITAN III/TOS TRACKING SUPPORT Tracking data and telemetry for the Mars Observer/Titan III/TOS launch will be provided by a combination of NASA and U.S. Air Force ground stations down range and around the world. Spacecraft X-band tracking data and telemetry will be received by the Deep Space Network (DSN) managed by the Jet Propulsion Laboratory, Pasadena, Calif. Titan III and TOS S-band tracking data and telemetry information and also coverage by C-band radars for ballistic trajectory information will be handled by U.S Air Force tracking stations and the NASA Spacecraft Tracking and Data Network (STDN). Data coverage also will be supplemented by U.S. Air Force Advanced Range Instrumentation Aircraft (ARIA). Two ARIA will provide support over the Atlantic Ocean and three other ARIA will provide support in the Indian Ocean region. Following is a partial list of primary tracking station locations and the role they play, either S-band for telemetry and tracking data or C-band for radar coverage and the span of time during the flight when data can be supplied if the launch occurs at the opening of the launch window: % Merritt Island/Cape Canaveral (NASA S-band/USAF S-band C-Band) 0:00-8:00 % Jupiter Inlet (USAF S-band/C-band) 0:30 - 8:05 % Bermuda (NASA S-band/C-band) 4:12 - 10:48 % Antigua Island (USAF S-band/C-band) 6:10 - 11:48 % ARIA-Atlantic Region (USAF S-band) 13:00 - 17:00 % Canberra, Australia (NASA S-band/X-band) 49:00 - end of support Communication After Launch NASA's DSN has the responsibility to communicate with the Mars Observer following injection into its trajectory to Mars. The three Deep Space Communications Complexes, located in Goldstone, Calif., Madrid, Spain and Canberra, will provide the air-to-ground links communication links with the spacecraft in Mars orbit. At its maximum distance from Earth, the time required for a signal to be sent to the spacecraft and be returned to Earth (called the round trip light time) will be approximately 40 minutes. Communications links which tie together all elements of the project team on Earth are provided by the NASA Communications Network (NASCOM) and the Program Support Communications Network (PSCN). NASA's Office of Space Communications provides the overall program management for the communication system. The STDN and NASCOM networks are managed by GSFC. The PSCN is managed by the Marshall Space Flight Center, Huntsville, Ala. The DSN is managed by JPL, in concert with Spain and Australia. SALIENT FACTS ON SPEED AND DISTANCE Speed in Earth orbit (with respect to Earth) 17,300 mph (7.73 km/s) Speed at TOS burnout (with respect to Earth) 25,700 mph (11.5 km/s) Average speed during cruise (with respect to Sun) 56,000 mph (25.0 km/s) Speed before Mars orbit insertion maneuver (with respect to Mars) 11,800 mph (5.28 km/s) Speed after Mars orbit insertion maneuver (with respect to Mars) 10,200 mph (4.56 km/s) Speed in mapping orbit (with respect to Mars) 7,500 mph (3.35 km/s) Distance traveled between Earth and Mars 450 million miles (7.24 x 108 km) Distance from Earth at Mars arrival 210 million miles (3.4 x 108 km ) Distance from Earth during Min: 62 Mmi (108 km) mapping phase Max: 230 Mmi (3.7 x 108 km) Time for command to reach spacecraft Min: 5.5 minutes during mapping phase Max: 20.5 minutes Maximum acceleration on spacecraft (postlaunch) 0.1 G (occurs during transfer to low orbit) Navigation target diameter at Mars 300 miles (480 km) (less than 1/10 of planet diameter) SCIENCE OPERATIONS The Mars Observer mission operations at the Jet Propulsion Laboratory will be supported by NASA's Deep Space Network (DSN) and the JPL Advanced Multimission Operations System. The 34-meter (111- foot), high-efficiency subnetwork, the newest of the DSN antenna subnets, will provide daily uplink and downlink communications with the spacecraft at X-band frequencies of 8.4 gigahertz. The 70- meter (230-foot) antenna network also will provide periodic very-long-baseline interferometry and real-time, high-rate telemetry and radio science support to the mission. The DSN facilities are located in Pasadena and Goldstone, Calif.; Canberea, Australia; and Madrid, Spain. The instrument scientists will remain at their home institutions, from which they will access Mars Observer data via a project database at JPL. Using workstations and electronic communications links, scientists also will be connected to the mission planning activities at JPL. In the same way, data products returned to the JPL database from the home institution for each of the instruments will be sent electronically to other investigators at their home institutions. This will allow scientists to have ready access to science data without moving to JPL for the duration of the mission. More than 60 workstations will be connected to the project database at JPL, a centralized repository for downlink science and engineering telemetry data, ancillary data including navigation data, and uplink command and sequence data. This database, with about 30 gigabytes of on- line storage, will be electronically available to the science instrument investigators via NASCOM data links. During the mapping phase, the instrument investigations will return processed science data products to the database at JPL for access by the interdisciplinary scientists and the other investigation teams. Forty-two participating scientists from universities and scientific institutions in the United States, Russia, France, Germany and Great Britain will join the permanent Mars Observer science team once the mission is under way in October 1992. MARS OBSERVER INVESTIGATORS Gamma Ray Spectrometer (GRS) TEAM LEADER: William V. Boynton, University of Arizona James R. Arnold, University of California, San Diego Peter Englert, San Jose State University William C. Feldman, Los Alamos National Laboratory Albert E. Metzger, Jet Propulsion Laboratory Robert C. Reedy, Los Alamos National Laboratory Steven W. Squyres, Cornell University Jacob L. Trombka, Goddard Space Flight Center Heinrich Wnke, Max Planck Institute for Chemistry Johannes Brckner, Max Planck Institute for Chemistry Darrell M. Drake, Los Alamos National Laboratory Larry G. Evans, Computer Sciences Corporation John G. Laros, Los Alamos National Laboratory Richard D. Starr, Catholic University Yu A. Surkov, Russia Mars Observer Camera (MOC) PRINCIPAL INVESTIGATOR: Michael C. Malin, Malin Space Science Systems, Inc. G. Edward Danielson Jr., California Institute of Technology Andrew P. Ingersoll, California Institute of Technology Laurence A. Soderblom, U.S. Geological Survey Joseph Veverka, Cornell University Merton E. Davies, The RAND Corporation William K. Hartmann, Science Applications International Philip B. James, University of Toledo Alfred S. McEwan, U.S. Geological Survey Peter C. Thomas, Cornell University Thermal Emission Spectrometer (TES) PRINCIPAL INVESTIGATOR: Philip R. Christensen, Arizona State University Donald A. Anderson, Arizona State University Stillman C. Chase, Santa Barbara Research Center Roger N. Clark, U.S. Geological Survey Hugh H. Kieffer, U.S. Geological Survey Michael C. Malin, Malin Space Science Systems, Inc. John Pearl, Goddard Space Flight Center Todd R. Clancy, University of Colorado Barney J. Conrath, Goddard Space Flight Center R.O. Kuzmin, Russia Ted L. Roush, San Francisco State University A.S. Selivanov, Russia Pressure Modulator Infrared Radiometer (PMIRR) PRINCIPAL INVESTIGATOR: Daniel J. McCleese, Jet Propulsion Laboratory Robert D. Haskins, Jet Propulsion Laboratory Conway B. Leovy, University of Washington David A. Paige, University of California, Los Angeles John T. Schofield, Jet Propulsion Laboratory Fredric Taylor, University of Oxford Richard W. Zurek, Jet Propulsion Laboratory Michael D. Allison, Goddard Space Flight Center Jeffrey R. Barnes, Oregon State University Terry Z. Martin, Jet Propulsion Laboratory Peter L. Read, University of Oxford Mars Observer Laser Altimeter (MOLA) PRINCIPAL INVESTIGATOR: David E. Smith, Goddard Space Flight Center Herbert V. Frey, Goddard Space Flight Center James B. Garvin, Goddard Space Flight Center James W. Head, Brown University James G. Marsh, Goddard Space Flight Center Duane Muhleman, California Institute of Technology Gordon H. Pettengill, Massachusetts Institute of Technology Roger J. Phillips, Southern Methodist University Sean C. Solomon, Massachusetts Institute of Technology Maria T. Zuber, Goddard Space Flight Center H. Jay Zwally, Goddard Space Flight Center Bruce W. Banerdt, Jet Propulsion Laboratory Thomas C. Duxbury, Jet Propulsion Laboratory Radio Science (RS) TEAM LEADER: G. Leonard Tyler, Stanford University Georges Balmino, Centre National d'Etudes Spatiales (CNES), France David Hinson, Stanford University William L. Sjogren, Jet Propulsion Laboratory David E. Smith, Goddard Space Flight Center Richard Woo, Jet Propulsion Laboratory E. L. Akim, Russia John W. Armstrong, Jet Propulsion Laboratory Michael F. Flasar, Goddard Space Flight Center Richard A. Simpson, Stanford University Magnetometer and Electron Reflectometer (MAG/ER) PRINCIPAL INVESTIGATOR: Mario H. Acuna, Goddard Space Flight Center Kinsey S. Anderson, University of California, Berkeley Sigfried Bauer, University of Graz Charles W. Carlson, University of California, Berkeley Paul Cloutier, Rice University John E. P. Connerney, Goddard Space Flight Center David W. Curtis, University of California, Berkeley Robert P. Lin, University of California, Berkeley Michael Mayhew, National Science Foundation Norman F. Ness, University of Delaware Henri Reme, University of Paul Sabatier Peter J. Wasilewski, Goddard Space Flight Center M. Menvielle, University of Paris Sud, France Diedrich Mhlmann, German Aerospace Research Establishment, Germany A.A. Ruzmaikin, Russia James A. Slavin, Goddard Space Flight Center A.V. Zakharov, Russia INTERDISCIPLINARY SCIENTISTS Raymond E. Arvidson, Washington University Bruce Fegley Jr., Washington University Michael H. Carr, U.S. Geological Survey A. T. Bazilevsky, Russia Matthew Golombek, Jet Propulsion Laboratory Harry Y. McSween Jr., University of Tennessee Andrew P. Ingersoll, California Institute of Technology Howard Houben, Space Physics Research Institute Bruce M. Jakosky, University of Colorado L.V. Ksanfomality, Russia Aaron P. Zent, Search for Extraterrestrial Intelligence (SETI) Institute James B. Pollack, Ames Research Center Robert M. Haberle, Ames Research Center V.I. Moroz, Russia Laurence A. Soderblom, U.S. Geological Survey Ken Herkenhoff, Jet Propulsion Laboratory Bruce C. Murray, California Institute of Technology MARS OBSERVER MANAGEMENT NASA HEADQUARTERS, WASHINGTON, D.C. Office of Space Science and Applications Dr. Lennard A. Fisk, Associate Administrator Alphonso V. Diaz, Deputy Associate Administrator Dr. Wesley T. Huntress, Director, Solar Systems Exploration Div. Douglas R. Broome, Deputy Director, Solar System Exploration Div. Dr. William L. Piotrowski, Chief, Flight Programs Branch and Mars Observer Program Manager William C. Panter, Mars Observer Deputy Program Manager Dr. Bevin M. French, Mars Observer Program Scientist Guenter K. Strobel, Planetary Flight Support Manager Charles R. Gunn, Director, Expendable Launch Vehicles Office B.C. Lam, Upper Stages Program Manager Office of Space Communications Charles T. Force, Associate Administrator for Space Communications Jerry J. Fitts, Deputy Associate Administrator for Space Communications Robert M. Hornstein, Director, Ground Networks Div. JET PROPULSION LABORATORY, PASADENA, CALIF. Dr. Edward C. Stone, Director Larry N. Dumas, Deputy Director John R. Casani, Assistant Laboratory Director, Flight Projects David D. Evans, Mars Observer Project Manager Glenn E. Cunningham, Mars Observer Deputy Project Director Dr. Arden L. Albee, Mars Observer Project Scientist Frank D. Palluconi, Mars Observer Deputy Project Scientist Thomas E. Thorpe, Mars Observer Science Manager George D. Pace, Mars Observer Spacecraft Manager Gary L. Reisdorf, Mars Observer Payload Manager Dr. Saterios S. Dallas, Mars Observer Mission Manager Joseph Shaffer, Mars Observer Launch Vehicle Manager Gail K. Robinson, Mars Observer Administration and Finance Manager T. David Linich, Multi-Mission Operations Support Manager Eugene S. Burke, Multi-Mission Operations Manager Marvin Traxler, Tracking and Telecommunications Data Systems Manager Dr. Peter Poon, Coordinator with Multimission Operations Systems Center KENNEDY SPACE CENTER, FLA. Robert L. Crippen, Director James A. "Gene" Thomas, Deputy Director John T. Conway, Director, Payload Management and Operations James L. Womack, Director, Expendable Vehicles George E. Looschen, Chief, Launch Operations Division David C. Bragdon, Launch Vehicle/Payload Integration Manager Floyd A. Curington, Chief, Project Planning and Support James W. Meyer, Tracking and Range Coordinator JoAnn H. Morgan, Director, Payload Projects Management Gayle C. Hager, Mars Observer Launch Site Support Manager Julie A. Scheringer, TOS Launch Site Support Manager LEWIS RESEARCH CENTER, CLEVELAND Lawrence J. Ross, Director Dr. J. Stuart Fordyce, Deputy Director Thomas H. Cochran, Director, Space Flight Systems John W. Gibb, Manager, Launch Vehicle Project Office Steven V. Szabo, Jr., Director, Engineering Directorate Edward G. Stakolich, Titan Mission Manager Edwin R. Procasky, Chief, System Engineering Office Edwin T. Muckley, Chief, Mission and Vehicle Integration Office MARSHALL SPACE FLIGHT CENTER, HUNTSVILLE, ALA. Thomas J. Lee, Director Dr. J. Wayne Littles, Deputy Director Sidney P. Saucier, Manager, Space Systems Projects Alvin E. Hughes, Manager, Upper Stage Projects Robert W. Hughes, Upper Stages Chief Engineer GODDARD SPACE FLIGHT CENTER, GREENBELT, MD. Dr. John Klineberg, Director Peter T. Burr, Deputy Director Dr. Dale W. Harris, Director, Flight Projects Directorate Jeremiah J. Madden, Associate Director of Flight Projects for Earth Observing System (EOS) Martin J. Donohoe, Project Manager for EOS Instruments Projects Dr. Douglas D. McLennan, Manager for Mars Observer GRS Bertrand L. Johnson, Jr., Manager for Mars Observer MOLA
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