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The Space Shuttle Enterprise

Enterprise during a captive flight
Enterprise during a captive flight 
The Space Shuttle Enterprise (NASA Orbiter Vehicle Designation: OV-101) was the first Space Shuttle orbiter. It was built for NASA as part of the Space Shuttle program to perform test flights in the atmosphere.[1] It was constructed without engines or a functional heat shield, and was therefore not capable of spaceflight. On September 17, 1976, the first full scale prototype was completed.[2]
Originally, Enterprise had been intended to be refitted for orbital flight, which would have made it the second space shuttle to fly after Columbia.[1] However, during the construction of Columbia, details of the final design changed, particularly with regard to the weight of the fuselage and wings. Refitting Enterprise for spaceflight would have involved dismantling the orbiter and returning the sections to subcontractors across the country. As this was an expensive proposition, it was determined to be less costly to build Challenger around a body frame (STA-099) that had been created as a test article.[1] Similarly, Enterprise was considered for refit to replace Challenger after the latter was destroyed, but Endeavour was built from structural spares instead.[1][3]
 
Differences between Enterprise and future shuttles
 
The design of OV-101 was not the same as that planned for OV-102, the first flight model; the aft fuselage was constructed differently, and it did not have the interfaces to mount OMS pods. A large number of subsystems—ranging from main engines to radar equipment—were not installed on Enterprise, but the capacity to add them in the future was retained, as NASA originally intended to refit the orbiter for spaceflight at the conclusion of its testing. Instead of a thermal protection system, its surface was primarily covered with simulated tiles made from polyurethane foam. Fiberglass was used for the leading edge panels in place of the reinforced carbon-carbon ones of spaceflight-worthy orbiters. Only a few sample thermal tiles and some Nomex blankets were real.[4] Enterprise used fuel cells to generate its electrical power, but were not sufficient to power the orbiter for spaceflight.[5]
Enterprise also lacked RCS thrusters (which were useless in atmospheric flight) and hydraulic mechanisms for the landing gear; the landing gear doors were simply opened through the use of explosive bolts and the gear dropped down solely by gravity.[5] As it was only used for atmospheric testing, Enterprise featured a large air spike mounted on its nose cap which had been used on the U-2 spy plane.
Enterprise was equipped with Lockheed-manufactured zero-zero ejection seats like those its sister Columbia had carried on its first four missions.[5]

  Service

 
Construction began on Enterprise on June 4, 1974.[1] Designated OV-101, it was originally planned to be named Constitution and unveiled on Constitution Day, September 17, 1976. A letter-writing campaign by Trekkies to President Gerald Ford asked that the orbiter be named after the Starship Enterprise, featured on the television show Star Trek. Although Ford did not mention the campaign, the president, saying he was "partial to the name" Enterprise, directed NASA officials to change the name.[3][6]
In mid-1976 the orbiter was used for ground vibration tests, allowing engineers to compare data from an actual flight vehicle with theoretical models.[1]
On September 17, 1976, Enterprise was rolled out of Rockwell's plant at Palmdale, California. In recognition of its fictional namesake, Star Trek creator Gene Roddenberry and most of the principal cast of the original series of Star Trek were on hand at the dedication ceremony.[7]
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