Spaceline - Covering the Past, Present and Future of Cape Canaveral
SPACE SHUTTLE ENTERPRISE (OV-101) Fact Sheet
Written and Edited by Cliff Lethbridge
Contract Awarded: July 26, 1972
Final Assembly Completed: March 12, 1975
Factory Rollout: September 17, 1976
Space Shuttle Enterprise was originally intended by NASA to carry the name Constitution. Several U.S. Navy vessels had carried that name, including the famous "Old Ironsides" frigate Constitution launched in 1797 and still on display at the Boston Navy Yard.
NASA also considered the name Constitution to be appropriate for the U.S. Bicentennial, which was being commemorated when this, the first Space Shuttle, was rolled out of the factory in 1976.
However, fans of the television series "Star Trek" mounted an effort to have the first Space Shuttle named Enterprise in honor of the fictional starship. In 1976, the White House received about 100,000 letters requesting the name Enterprise.
NASA relented, and changed the name from Constitution to Enterprise prior to the rollout of the Space Shuttle from the factory. NASA cited the fact that several U.S. Navy vessels had also carried the name Enterprise, not the least of which was the first nuclear powered aircraft carrier.
Although Enterprise looked quite similar to Space Shuttles which followed, the vehicle was never destined to fly in space. During the summer of 1976, Enterprise acted as a test bed for Horizontal Ground Vibration Tests (HGVT) conducted at the Rockwell manufacturing plant in Palmdale, California.
HGVT tests were designed to test the structural integrity of Space Shuttles, with particular emphasis on how the vehicle responded to simulated launch and landing conditions. Since these tests were in-house simulations only, Enterprise did not contain much of the equipment it would need for actual flights.
Following the conclusion of HGVT tests, Enterprise was outfitted with the equipment necessary to perform a number of actual flight tests. But since these test flights would not actually carry Enterprise into space, the vehicle differed dramatically from those Space Shuttles built to fly in space.
For example, Enterprise carried no Main Propulsion System plumbing, fuel lines or tankage of any kind. The Space Shuttle Main Engines (SSME) carried aboard Enterprise were mock-ups only, as were a number of other propulsion system components.
Enterprise carried active fuel cells to provide power to the vehicle, but these were simpler and lighter than those used on space faring Space Shuttles. The payload bay of Enterprise contained no mounting hardware for cargo packages, and the payload bay door contained no hydraulic mechanisms to allow it to open and close.
In order to save money, Enterprise did not carry any actual thermal protection system tiles that would be necessary to protect a Space Shuttle from the intense heat of re-entry. Instead, the thermal protection system tiles were simulated for Enterprise using black and white polyurethane foam bonded to its outer skin.
The flight deck controls used by the crews performing flight tests aboard Enterprise were much simpler than those used during space flight. Enterprise contained none of the guidance equipment necessary to carry out a space flight. The crew compartment was largely empty since Enterprise would never need to support a crew in space.
One important feature incorporated into Enterprise was an escape system for its occupants. A Lockheed zero-zero ejection seat escape mechanism was installed in the flight deck. In the event of an emergency, two blow-out aluminum panels located above the pilots could allow them to escape via the ejection seats.
Several windows incorporated into operational Space Shuttles were absent on Enterprise. These included the two windows in the aft crew compartment overlooking the payload bay and the overhead rendezvous windows on the flight deck. These windows were all covered by aluminum panels on Enterprise.
For flight testing, Enterprise was ballasted to replace the weight of equipment that would be carried aboard Space Shuttles performing space missions. The landing gear was operated through the use of explosive bolts and gravity. No hydraulic mechanisms or manual back-up systems were incorporated into the landing system of Enterprise.
Enterprise did, however, carry all of the aerodynamic hardware necessary to complete a number of critical Space Shuttle flight tests. One of the important pieces of equipment carried aboard Enterprise and not carried aboard operational Space Shuttles was a long, pointed air data probe which stuck prominently out the nose of the vehicle.
The Enterprise Approach and Landing Tests were broken down into four categories:
1. Taxi Tests, intended to verify the taxi characteristics of the 747 Shuttle Carrier Aircraft (SCA) while carrying a Space Shuttle. These were runway taxi tests only, and did not involve flight. The three Taxi Tests were conducted on February 15, 1977. No crew flew aboard Enterprise for these tests.
2. Captive-Inactive Flights, intended to verify the performance, stability and control of the SCA while carrying a Space Shuttle in flight. The five Captive-Inactive Flights were conducted between February 18, 1977 and March 2, 1977. No crew flew aboard Enterprise for these tests.
3. Captive-Active Flights, intended to determine the best separation profile that Enterprise could utilize as it separated from the SCA during upcoming Free Flights, refine crew procedures and evaluate Enterprise flight systems. The three Captive-Active Flights were conducted between June 18, 1977 and July 26, 1977. A two-man crew flew aboard Enterprise for these tests.
4. Free Flights, intended to verify the airworthiness, integrated system operations, pilot-guided landing systems and automated landing systems of the Space Shuttle. The five Free Flights were conducted between August 12, 1977 and October 26, 1977. A two-man crew flew aboard Enterprise for these tests.
At the conclusion of the Enterprise Approach and Landing Tests, NASA certified the Space Shuttle as aerodynamically sound, and announced that no additional flight tests would be necessary. But Enterprise was not immediately retired.
Additional tests would be necessary if NASA hoped to achieve the first space flight of a Space Shuttle by 1979. In November, 1977 the SCA performed a series of four flights carrying Enterprise in the ferry configuration. No approach or landing tests were completed by Enterprise at this time.
Enterprise was then ferry flown to the NASA Dryden Flight Research Center in California to be modified for an upcoming series of tests at the NASA Marshall Space Flight Center (MSFC) at Huntsville, Alabama. A series of Mated Vertical Ground Vibration Tests (MVGVT) were conducted on Enterprise at MSFC beginning in March, 1978.
The MVGVT tests were intended to subject Enterprise to a series of vibrations that the Space Shuttle might experience in flight. The elaborate and expensive MVGVT tests concluded in December, 1978.
At this point, NASA had considered returning Enterprise back to the Rockwell plant in California to be modified into an operational Space Shuttle. However, as Enterprise was in the process of being built and tested, NASA had introduced several major modifications to the Space Shuttle, and decided it would be too expensive to re-fit Enterprise.
Instead, NASA opted to modify an already existing high-fidelity Structural Test Article (STA-099) into what would become Space Shuttle Challenger. As a result, Enterprise was made available for another series of important tests.
On April 10, 1979 Enterprise was ferry flown from MSFC to the Kennedy Space Center (KSC). At KSC, Enterprise would be extensively used to test equipment and procedures that would be necessary to support the first space flight of a Space Shuttle.
Engineers at KSC had been using a Space Shuttle mock-up nicknamed Pathfinder, which was built at MSFC in 1977 for facilities tests there and then transported to KSC by barge in 1978. Although Pathfinder was useful in certain tests at KSC through 1979, Enterprise was welcomed as a much more realistic tool for validating operational procedures.
Soon after Enterprise arrived at KSC, it was transported to the Vehicle Assembly Building (VAB) and mated to an external tank and inert set of solid rocket boosters. Enterprise became the first Space Shuttle actually rolled out to the launch pad. Enterprise was rolled out to Launch Pad 39A on May 1, 1979.
Enterprise spent nearly three months on the launch pad, and supported a number of operational tests there, including vital tests of the launch pad crew escape system. On July 23, 1979 Enterprise was rolled back to the VAB and subsequently demated from the external tank and solid rocket boosters.
In early August, 1979 Enterprise was ferry flown to Vandenberg Air Force Base, California. Workers constructing a Space Shuttle launch facility at Vandenberg were invited to view Enterprise as it sat atop the SCA.
On August 16, 1979 Enterprise was ferry flown to Edwards Air Force Base, California, demated from the SCA and eventually transported overland to the Rockwell plant in Palmdale, California on October 30, 1979. Here, certain parts of Enterprise were removed and refurbished for use on other Space Shuttles.
Enterprise was returned to Edwards Air Force Base on September 6, 1981 where it would remain stored for almost two years. Enterprise became the first Space Shuttle to travel abroad when it was ferry flown to France for the Paris Air Show in May, 1983. Enterprise also made visits to Germany, Italy, England and Canada through June, 1983.
After being returned to Edwards Air Force Base, Enterprise was ferry flown to Mobile, Alabama in March, 1984. The Space Shuttle was then transported by barge to the World's Fair at New Orleans on April 5, 1984 where it remained on display through the end of the Fair.
In late 1984, Enterprise was ferry flown to Vandenberg Air Force Base, California. There, like it had done several years earlier at KSC, Enterprise was used to validate operational Space Shuttle processing systems.
After the Vandenberg tests were completed, Enterprise was ferry flown to the NASA Dryden Flight Research Center on May 24, 1985. On September 20, 1985 Enterprise was ferry flown to KSC, where it was placed on display next to a Saturn V rocket outside the VAB.
On November 18, 1985 Enterprise was ferry flown to its permanent home, a facility of the National Air and Space Museum constructed at Dulles Airport in Washington, D.C.
During the week of June 8, 1987 Enterprise was used at Dulles Airport to test a prototype Space Shuttle landing arresting barrier, a concept proposed during the Challenger accident investigation. The tests were successful, but the barriers were never applied to the Space Shuttle program.
Following these tests, Enterprise was placed in long-term storage in a hangar at Dulles Airport, awaiting the construction of a display facility at the airport large enough to allow the Space Shuttle to be placed on permanent display.
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