 Simulated view of VentureStar inlow Earth orbit, having released its payload | |
| Function | Crewed Re-usableSpaceplane |
|---|---|
| Manufacturer | Lockheed Martin |
| Country of origin | United States |
| Size | |
| Height | 38.7 m (127 ft)[1] |
| Diameter | 39.0 m (128.0 ft)[2] |
| Mass | 1,000,000 kg (2,200,000 lb)[1] |
| Stages | 1 |
| Capacity | |
| Payload toLEO | |
| Mass | 20,000 kg (44,000 lb)[1] |
| Launch history | |
| Status | Cancelled |
| Launch sites | Kennedy,LC-39A |
| Total launches | 0 |
| First stage – VentureStar | |
| Powered by | 7Rocketdyne RS-2200Linear Aerospikes[1] |
| Maximum thrust | 3,010,000 lbf (13.4 MN)[1] |
| Propellant | LOX/LH2[1] |
VentureStar was asingle-stage-to-orbitreusable launch system proposed byLockheed Martin and funded by the U.S. government. The goal was to replace theSpace Shuttle by developing a re-usablespaceplane that could launch satellites into orbit at 1/10 of the cost. While the requirement was for an uncrewed launcher, it was expected to carry passengers as cargo. The VentureStar would have had a wingspan of 68 feet (20.7 m), a length of 127 feet (38.7 m), and would have weighed roughly 1,000tonnes (2.2 million lb).
VentureStar was intended to be a commercialsingle-stage-to-orbit vehicle that would be launched vertically, but return to Earth as an airplane. Flights would have been leased toNASA as needed. After failures with theX-33 subscale technology demonstrator test vehicle, funding was cancelled in 2001.
VentureStar was essentially a bigger version of the X-33 but was not produced.[3] The X-33 had ongoing problems meeting performance requirements for the carbon fiber hydrogen fuel tank.[3] There were a number of other technologies that were part of the program, including the linearaerospike rocket engine. One point of praise was the metallic thermal protection system (TPS) developed byBF Goodrich.[3]
VentureStar's engineering and design would have offered numerous advantages over theSpace Shuttle, notably considerable savings in time and materials, as well as increased safety.[4] VentureStar was expected to launch satellites into orbit at $2,000 USD per kilogram, 1/10 of the Space Shuttle's cost of $20,000 USD per kilogram.
Readying VentureStar for flight would have dramatically differed from that of the Space Shuttle. Unlike theSpace Shuttle orbiter, which had to be lifted and assembled together with several other heavy components (a largeexternal tank, plus twosolid rocket boosters), VentureStar was to be simply inspected in ahangar similarly to an airplane.[4]
Also unlike the Space Shuttle, VentureStar would not have relied uponsolid rocket boosters, which had to be hauled out of the ocean and then refurbished after each launch.[4] Furthermore, design specifications called for the use of linearaerospike engines that maintain thrust efficiency at all altitudes, whereas the Shuttle relied upon conventional nozzle engines which achieve maximum efficiency at only a certain altitude.[4]
VentureStar would have used a new metallic thermal protection system, safer and cheaper to maintain than the ceramic protection system used on the Space Shuttle. VentureStar's metallic heat shield would have eliminated 17,000 between-flight maintenance hours typically required to satisfactorily check (and replace if needed) the thousands of heat-resistantceramic tiles that composed the Shuttle heat shield.[4]
VentureStar was expected to be safer than most modern rockets.[4] Whereas most modern rockets fail catastrophically when an engine fails, VentureStar would have a thrust reserve in each engine in the event of an emergency.[4] For example, if an engine on VentureStar failed during ascent, another engine would shut off to counterbalance the failed thrust, and each of the remaining working engines could throttle up to safely continue the mission.[4]
Unlike the Space Shuttle, whose solid rocket boosters produced chemical wastes, primarilyhydrogen chloride, during launch, VentureStar's exhaust would have been composed of only water vapor, since VentureStar's main fuels would have been onlyliquid hydrogen andliquid oxygen.[4] This would have given VentureStar the benefit of being environmentally clean.[4] VentureStar's simpler design would have excludedhypergolic propellants and evenhydraulics, relying instead upon electrical power for flight controls, doors and landing gear.[4]
Because of its lighter design, VentureStar would have been able to land at almost any major airport in an emergency,[4] whereas the Space Shuttle requiredmuch longer runways than available at most public airports.
The VentureStar program was cancelled in 2001 due to development cost concerns accompanied by technical problems and failures in theX-33 program, a program which was intended as proof-of-concept for some of the critical technologies that were to be implemented in the VentureStar. The failure during a test of the X-33's complex, multi-lobe composite-structure cryogenic hydrogen tank was one of the main reasons for the cancellation of both the X-33 and the VentureStar. Ultimately, the VentureStar program required too many technical advances at too high a cost to be viable.
Examples:[3]
One of the technological barriers at the time was the hydrogen fuel tank.[3] One positive was that several years later the performance requirements for such a hydrogen tank were achieved, as NASA gained more experience with cryogenic carbon fiber fuel tanks.[5]
On September 7, 2004,Northrop Grumman and NASA engineers unveiled a liquid hydrogen tank made of carbon fiber composite material that had demonstrated the ability for repeated fuelings and simulated launch cycles.[5] The tank was a simple cylinder, not the complex shape used for the X-33. Northrop Grumman concluded that these successful tests enabled the development and refinement of new manufacturing processes that allowed the company to build large composite tankswithout an autoclave; and design and engineering development of conformal fuel tanks appropriate for use on a single-stage-to-orbit vehicle.[6]
In the 2001 novella and 2015 novelLash-Up byLarry Bond and Chris Carlson, the VentureStar prototype is converted into an armed spacecraft namedDefender in order to protect US space assets from China, which is using aspace gun to destroyGPS satellites.[7][8]
InJohn Varley's novelRed Thunder and sequels, one of the major protagonists is a former VentureStar pilot.
In the television seriesStar Trek: Enterprise, an operational VentureStar spaceplane is included in the opening credits as part of the history of human spaceflight.[9]
In the television seriesSpace Island One, a fleet of VentureStars resupply the titular commercial space station.
In the 2009 science fiction filmAvatar, an interstellar space ship taking the characters to and from theAlpha Centauri system is named theISV Venture Star.
