| Enterprise | |
|---|---|
 Enterprise in flight in 1977, during ALT-13 | |
| Type | Spaceplane |
| Class | Space Shuttle orbiter |
| Eponym | USS Enterprise (NCC-1701) |
| Other name | Constitution (1975–1977) |
| Serialno. | OV-101 |
| Owner | NASA |
| Manufacturer | Rockwell International |
| History | |
| First flight |
|
| Last flight |
|
| Flights | 5 |
| Flight time | 20 m, 58 s above Earth |
| Fate | Prototype |
| Location | |
| Space Shuttle orbiters | |
Space ShuttleEnterprise (Orbiter Vehicle Designation:OV-101) was the firstorbiter of theSpace Shuttle system. Rolled out on September 17, 1976, it was built forNASA as part of theSpace Shuttle program to perform atmospheric test flights after being launched from amodified Boeing 747.[1] It was constructed withoutengines or a functionalheat shield. As a result, it was not capable ofspaceflight.[2]
Originally,Enterprise had been intended to be refitted fororbital flight to become the second space-rated orbiter in service.[1] However, during the construction ofSpace Shuttle Columbia, details of the final design changed, making it simpler and less costly to build Challenger around a body frame that had been built as atest article.[1] Similarly,Enterprise was considered for refit to replaceChallenger after the latterwas destroyed, but Endeavour was built from structural spares instead.[1][3]
Enterprise was restored and placed on display in 2003 at theSmithsonian's newSteven F. Udvar-Hazy Center in Virginia.[4] Following theretirement of the Space Shuttle fleet, Discovery replacedEnterprise at the Udvar-Hazy Center, andEnterprise was transferred to theIntrepid Museum in New York City, where it has been on display since July 2012.[5]
The design ofEnterprise was not the same as that planned for Columbia, the first flight model; the aft fuselage was constructed differently, and it did not have the interfaces to mountOMS pods. A large number of subsystems—ranging from main engines to radar equipment—were not installed onEnterprise, 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 athermal protection system, its surface was primarily covered with simulated tiles made frompolyurethane foam.Fiberglass was used for the leading edge panels in place of thereinforced carbon–carbon ones of spaceflight-worthy orbiters. Only a few sample thermal tiles and someNomex blankets were real.[6]Enterprise usedfuel cells to generate its electrical power, but these were not sufficient to power the orbiter for spaceflight.[7]
Enterprise also lackedreaction control system thrusters and hydraulic mechanisms for the landing gear; the landing gear doors were simply opened through the use ofexplosive bolts and the gear dropped down solely by gravity.[7] As it was only used for atmospheric testing,Enterprise featured a largenose probe mounted on its nose cap, common on test aircraft because the location provides the most accurate readings for the test instruments, being mounted out in front of the disturbed airflow.
Enterprise was equipped withLockheed-manufacturedzero-zero ejection seats like those its sister Columbia carried on its first four missions.[7]
| Date | Milestone[8] |
|---|---|
| 1972 July 26 | Contract Award toNorth American Rockwell |
| 1972 August 9 | Construction authorization from NASA |
| 1974 June 4 | Start structural assembly of crew module atDowney plant |
| 1974 August 26 | Start structural assembly of aft fuselage at Downey plant |
| 1975 March 27 | Mid fuselage arrives at Palmdale fromGeneral Dynamics |
| 1975 May 23 | Wings arrive at Palmdale fromGrumman |
| 1975 May 25 | Vertical stabilizer arrives at Palmdale fromFairchild Republic |
| 1975 August 25 | Start of Final Assembly |
| 1975 September 9 | Aft fuselage on dock, Palmdale |
| 1975 October 31 | Lower forward fuselage on dock, Palmdale |
| 1975 December 1 | Upper forward fuselage on dock, Palmdale |
| 1976 January 16 | Crew module on dock, Palmdale |
| 1976 March 3 | Payload bay doors on dock, Palmdale |
| 1976 March 12 | Complete final assembly and closeout systems installation |
| 1976 March 15 | Start functional checkout |
| 1976 June | Complete functional checkout, start ground vibration and proof load tests |
| 1976 September 17 | Rollout from Palmdale[9] |
| 1976 October–November | Start systems retest, complete integrated systems checkout |
| 1977 February 18 | First captive flight |
| 1977 June 18 | First crewed captive flight[10] |
| 1977 August 12 | First free flight |
Construction began onEnterprise on June 4, 1974.[1] Designated OV-101, it was originally planned to be namedConstitution and unveiled onConstitution Day, September 17, 1976. Fans ofStar Trek askedUS PresidentGerald Ford, through a letter-writing campaign, to name the orbiter after the television show's fictional starship,USSEnterprise.[11]
In an official memo, White House advisors cited "hundreds of thousands of letters" fromTrekkies, "one of the most dedicated constituencies in the country", as a reason for giving the shuttle the name.[12] Although Ford did not publicly mention the campaign, the president said that he was "partial to the name"Enterprise, and directed NASA officials to change the name.[3][13][14][11]
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 ofRockwell's plant atPalmdale, California. In recognition of its fictional namesake,Star Trek creatorGene Roddenberry and most of the principal cast of the original series ofStar Trek were on hand at the dedication ceremony.[15]
On January 31, 1977,Enterprise was taken by road toDryden Flight Research Center atEdwards Air Force Base to begin operational testing.[1][16]
While at NASA DrydenEnterprise was used by NASA for a variety of ground and flight tests intended to validate aspects of the shuttle program.[17] The initial nine-month testing period was referred to by the acronymALT, for "Approach and Landing Test".[1][18] These tests included a maiden "flight" on February 18, 1977, atop aBoeing 747Shuttle Carrier Aircraft (SCA) to measure structural loads and ground handling and braking characteristics of the mated system. Ground tests of all orbiter subsystems were carried out to verify functionality prior to atmospheric flight.[10]
The matedEnterprise/SCA combination was then subjected to five test flights withEnterprise uncrewed and unactivated. The purpose of these test flights was to measure the flight characteristics of the mated combination. These tests were followed with three test flights withEnterprise crewed to test the shuttle flight control systems.[1]
On August 12, 1977,Enterprise flew on its own for the first time.[19]Enterprise underwent four more free flights where the craft separated from the SCA and was landed under astronaut control. These tests verified the flight characteristics of the orbiter design and were used to carry out several aerodynamic and weight configurations.[18] The first three flights were flown with a tailcone placed at the end ofEnterprise's aft fuselage, which reduced drag and turbulence when mated to the SCA. The final two flights saw the tailcone removed and mockup main engine nozzles installed. On the fifth and final glider flight,pilot-induced oscillation problems were revealed, which had to be addressed before the first orbital launch occurred.[17]
Following the conclusion of the ALT test flight program, on March 13, 1978,Enterprise was flown once again, but this time halfway across the country to NASA'sMarshall Space Flight Center (MSFC) inAlabama for the Mated Vertical Ground Vibration Testing (MGVT). The orbiter was lifted up on a sling very similar to the one used at Kennedy Space Center and placed inside the Dynamic Test Stand building, and mated to the Vertical Mate Ground Vibration Test tank (VMGVT-ET), which in turn was attached to a set of inert Solid Rocket Boosters (SRB) to form a complete shuttle launch stack, and marked the first time in the program's history that all Space Shuttle elements, an Orbiter, an External Tank (ET), and two SRBs, were mated together. During the course of the program,Enterprise and the rest of the launch stack would be exposed to a punishing series of vibration tests simulating as closely as possible those expected during various phases of launch, some tests with and others without the SRBs in place.[20]
At the conclusion of this testing,Enterprise was due to be taken back to Palmdale for retrofitting as a fully spaceflight capable vehicle. Under this arrangement,Enterprise would be launched on its maiden spaceflight in July 1981 to launch a communications satellite and retrieve theLong Duration Exposure Facility, then planned for a 1980 release on the first operational orbiter,Columbia. Afterward,Enterprise would conduct twoSpacelab missions.[21] However, in the period between the rollout ofEnterprise and the rollout ofColumbia, a number of significant design changes had taken place, particularly with regard to the weight of the fuselage and wings. This meant that retrofitting the prototype would have been a much more expensive process than previously realized, involving the dismantling of the orbiter and the return of various structural sections to subcontractors across the country. As a consequence, NASA made the decision to convert an incomplete Structural Test Article, numbered STA-099, which had been built to undergo a variety of stress tests, into a fully flight-worthy orbiter, which became Challenger.
| # | Date | Designation | Launch pad | Notes |
|---|---|---|---|---|
| 1 | July 16, 1981 | STS-17 | 39-A | Deployment ofIntelsat V satellite and retrieval ofLong Duration Exposure Facility |
| 2 | September 30, 1981 | STS-20 | 39-A | Spacelab mission |
| 3 | November 25, 1981 | STS-22 | 39-A | Spacelab mission |
Following the MGVT program and with the decision to not useEnterprise for orbital missions, it was ferried toKennedy Space Center on April 10, 1979. By June 1979, it was mated with an external tank and solid rocket boosters (known as aboilerplate configuration) and tested in a launch configuration atKSC Launch Complex 39A for a series of fit checks of the facilities there.[3]
After this period,Enterprise was returned to NASA'sDryden Flight Research Facility in September 1981.[23] In 1983 and 1984,Enterprise underwent an international tour visitingFrance,West Germany,Italy, theUnited Kingdom, andCanada.Enterprise also visitedCalifornia,Alabama, andLouisiana (while visiting the1984 Louisiana World Exposition).
Between November 1984 and May 1985,Enterprise was again mated with an external tank and solid rocket boosters in a boilerplate configuration for a series of fit checks of thenever-used shuttle facilities atVandenberg Air Force Base in California.[24][25][26]
On November 18, 1985,Enterprise was ferried to Washington, D.C., where it became property of theSmithsonian Institution and was stored in theNational Air and Space Museum's hangar atDulles International Airport.
After theChallenger disaster, NASA considered usingEnterprise as a replacement. Refitting the shuttle with all of the necessary equipment for it to be used in space was considered, but NASA decided to use spare parts constructed at the same time as Discovery and Atlantis to build Endeavour.[3]
In 2003 after thebreakup of Columbia during re-entry, theColumbia Accident Investigation Board conducted tests atSouthwest Research Institute, which used an air cannon to shoot foam blocks of similar size, mass and speed to that which struckColumbia at a test structure which mechanically replicated the orbiter wing leading edge. They removed a section of fiberglass leading edge fromEnterprise's wing to perform analysis of the material and attached it to the test structure, then shot a foam block at it.[27] While the leading edge was not broken as a result of the test, which took place on May 29, 2003, the impact was enough to permanently deform a seal and leave a thin gap 22 in (56 cm) long.[28][29][30] Since the strength of thereinforced carbon–carbon (RCC) onColumbia is "substantially weaker and less flexible" than the test section fromEnterprise, this result suggested that the RCC would have been shattered.[30] A section of RCC leading edge fromDiscovery was tested on June 6, to determine the effects of the foam on a similarly aged leading edge, resulting in a three in (7.6 cm) crack on panel 6 and cracking on a T-shaped seal between panels 6 and 7.[31][32] On July 7, using a leading edge fromAtlantis and focused on panel 8 with refined parameters stemming from theColumbia accident investigation, a second test created a ragged hole approximately 16 by 16 in (41 by 41 cm) in the RCC structure.[33][32] The tests clearly demonstrated that a foam impact of the typeColumbia sustained could seriously breach the protective RCC panels on the wing leading edge.[32]
The board determined that the probable cause of the accident was that the foam impact caused a breach of a reinforced carbon-carbon panel along the leading edge ofColumbia's left wing, allowing hot gases generated during re-entry to enter the wing and cause structural collapse. This causedColumbia to tumble out of control, breaking up with the loss of the entire crew.[34]
In 1984,Enterprise was on display during the1984 Louisiana World Exposition (World's Fair) in New Orleans.
From 1985 to 2003,[10]Enterprise was stored at theSmithsonian's hangar atWashington Dulles International Airport before it was restored and moved to the Smithsonian's newly builtNational Air and Space MuseumSteven F. Udvar-Hazy Center at Washington Dulles, where it was the centerpiece of the space collection.[35] On April 12, 2011, NASA announced that Discovery, the most traveled orbiter in the fleet, would replaceEnterprise in the Smithsonian's collection once theShuttle fleet was retired, with ownership ofEnterprise transferred to theIntrepid Museum in New York City. On April 17, 2012,Discovery was transported byShuttle Carrier Aircraft to Dulles fromKennedy Space Center, where it made several passes over the Washington D.C. metro area.[36][37] AfterDiscovery had been removed from the Shuttle Carrier Aircraft, both orbiters were displayed nose-to-nose outside the Steven F. Udvar-Hazy Center beforeEnterprise was made ready for its flight to New York.[38]
Space ShuttleEnterprise | |
.jpg) Enterprise being lifted onto the deck ofIntrepid in June 2012 | |
| Location | New York City |
|---|---|
| NRHP reference No. | 13000071 |
| Added to NRHP | March 13, 2013 |
On December 12, 2011, ownership ofEnterprise was officially transferred to theIntrepidMuseum in New York City.[39][40][41] In preparation for the anticipated relocation, engineers evaluated the vehicle in early 2010 and determined that it was safe to fly on the Shuttle Carrier Aircraft once again.[42] At approximately 13:40 UTC on April 27, 2012,Enterprise took off from Dulles International Airport en route to a fly-by over theHudson River, New York'sJFK International Airport, theStatue of Liberty, theGeorge Washington andVerrazano-Narrows Bridges, and several other landmarks in the city, in an approximately 45-minute "final tour". At 15:23 UTC,Enterprise touched down atJFK International Airport.[43][44]
The mobileMate-Demate Device and cranes were transported from Dulles to the ramp at JFK and the shuttle was removed from the SCA overnight on May 12, 2012, placed on a specially designed flat bed trailer and returned to Hangar 12.[45] On June 3 aWeeks Marine barge tookEnterprise toJersey City. The Shuttle sustained cosmetic damage to a wingtip when a gust of wind blew the barge towards a piling.[46] It was hoisted June 6 onto the Intrepid Museum in Manhattan.[47]
Enterprise went on public display on July 19, 2012, at the Intrepid Museum's new Space Shuttle Pavilion, a temporary shelter consisting of a pressurized, air-supported fabric bubble constructed on the aft end of the carrier's flight deck.[48]
On October 29, 2012, storm surges fromHurricane Sandy caused Pier 86, including the Intrepid Museum's visitor center, to flood, and knocked out the museum's electrical power and both backup generators. The loss of power caused the Space Shuttle Pavilion to deflate, and high winds from the hurricane caused the fabric of the Pavilion to tear and collapse around the orbiter. Minor damage was spotted on thevertical stabilizer of the orbiter, as a portion of the tail fin above the rudder/speedbrake had broken off.[49] The broken section was recovered by museum staff. While the pavilion itself could not be replaced for some time in 2013, the museum erected scaffolding and sheeting aroundEnterprise to protect it from the environment.[50]
By April 2013, the damage sustained toEnterprise's vertical stabilizer had been fully repaired, and construction work on the structure for a new pavilion was under way.[51] The pavilion and exhibit reopened on July 10, 2013.[52]
Enterprise was listed on theNational Register of Historic Places on March 13, 2013, reference number 13000071, in recognition of its role in the development of the Space Shuttle Program. The historic significance criteria are in space exploration, transportation, and engineering.[53]
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This article incorporatespublic domain material from websites or documents of theNational Aeronautics and Space Administration.
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