NASA X-38
X-38 | |
---|---|
X-38, Vehicle 132 | |
Role | Crew Return Vehicle |
Design group | DLR, Dassault Aviation
|
Built by | Scaled Composites (prototypes) |
First flight | 1999 |
Status | Canceled 29 April 2002 |
Primary users | ESA
|
Number built | 2 atmospheric prototypes 1 orbital prototype (90 % complete) |
Developed from | Martin-Marietta X-24
|
The X-38 was an experimental
The program would eventually develop a total of three
History
With crew being taken to the ISS by space shuttle, the maximum crew size for the ISS would be dependent on crew rescue capacity. Since it is imperative that the crew members be able to return to Earth in case of an unexpected emergency, a Crew Return Vehicle able to hold up to seven crew members was initially planned by the ISS program leadership. This would have allowed the full complement of seven astronauts to live and work on the ISS.
During the early years of ISS on-orbit construction, the crew was limited to three, corresponding to a single Russian
A small, in-house development study of the X-38 concept first began at Johnson Space Center (JSC) in early 1995; however, several types of emergency scenarios were recognized by NASA as early as 1992 that drove the need for crew return from the International Space Station:[4]
- A serious illness or injury to a station astronaut
- A fire or collision with space debris
- Grounding of the space shuttle so that it could not deliver life-sustaining supplies.
In early 1996, a contract was awarded to Scaled Composites, Inc., of Mojave, Calif., for the construction of three full-scale atmospheric test airframes. The first vehicle airframe was delivered to JSC in September 1996.[5]
Development
In an unusual move for an
Rob Meyerson, who later went on to become President of Blue Origin, was an early member of the team.[6]
The X-38 design used a wingless lifting body concept originally developed by the
The X-38 program used uncrewed mockups to test the CRV design. Flight models were indicated with the letter V for "Vehicle" followed by a number.
- X-38 V-131
- X-38 V-132
- X-38 V-131-R, which was the V-131 prototype reworked with a modified shell.
- X-38 V-201, which was an orbital prototype to be launched by the Space Shuttle.
- X-38 V-121, V-133 and V-301 were also foreseen, but were never built.
The X-38 V-131 and V-132 shared the
The X-38 V-131-R was designed at 80 percent of the size of a CRV [24.5 ft long (7.5 m), 11.6 ft wide (3.5 m), 8.4 ft high (2.6 m)], and featured the final redesigned shape (Two later versions, V-133 and V-201, were planned at 100 percent of the CRV size). The 80% scale versions were flown at 15,000 to 24,000 pound weight. The X-38 V-201 orbital prototype was 90 percent complete, but never flown.
In
Design
The X-38 was intended to be semi-permanently docked to the ISS. If the crew became sick or injured during the course of their mission, they would enter the rescue vehicle through a hatched docking mechanism. With execution of a short procedure, the crew return vehicles would automatically fly the crew members safely to Earth. Once undocked, the vehicle would be deorbited using a deorbital propulsion system (DPS). The eight-thruster DPS would adjust the spacecraft's attitude and retrofire to slow the X-38 down, allowing gravitational attraction to pull it back into Earth's atmosphere. A DPS module was developed by Aerojet and delivered to Johnson Space Center in 2002 for V-201.
Following the jettison of the DPS, the X-38 would have glided from orbit and used a steerable parafoil for its final descent and landing. The high speeds at which lifting body aircraft operate can make them challenging to land. The parafoil would have been used to slow the vehicle and make landing easier. The landing gear consisted of skids rather than wheels: the skids worked like sleds so the vehicle would have slid to a stop on the ground.
Both the shape and size of the X-38 were different from that of the Space Shuttle. The Crew Return Vehicle would have fitted into the payload bay of the shuttle. This does not, however, mean that it would have been small. The X-38 weighed 10,660 kg and was 9.1 meters long. The
The parafoil parachute, employed for landing, was derived from technology developed by the U.S. Army. This massive parafoil deploys in 5 stages for optimum performance. A drag chute would have been released from the rear of the X-38. This drag chute would have been used to stabilize and slow the vehicle down. The parafoil (area of 687 square meters) was then released. It would open in five steps (a process called staging). While the staging process only takes 45 seconds, it is important for a successful chute deployment. Staging prevents high-speed winds from tearing the parafoil.
The spacecraft's landing was to be completely automated. Mission Control would have sent coordinates to the onboard computer system. This system would also have used wind sensors and the
An Advanced Docking Berthing System (ADBS) was designed for the X-38 and the work on it led to the
The X-38 vehicle was also known as the X-35 (but that designation was already allocated by the USAF to Lockheed Martin's entry in the Joint Strike Fighter Program) and the X-CRV (experimental - Crew Return Vehicle).
Cancellation
Severe cost overruns plagued the ISS program during its development and construction during the late 1990s and early 2000s. To bring costs under control the International Space Station Management and Cost Evaluation (IMCE) Task Force was created. The task force introduced a new concept known as "American Core Complete", whereby the U.S. would unilaterally reduce the previously agreed-upon American contributions to the ISS while retaining its role as the controlling member of the International partners. Core Complete (as opposed to the originally planned "Station Complete") deleted the American Habitation Module, the American CRV, and Node-3 from the ISS design without any negotiations with international partners. NASA Administrator, Sean O'Keefe, appointed by President George W. Bush, stated in December 2001 that he intended to adhere to the recommendations of the IMCE, including the implementation of Core Complete. The X-38 project cancellation was announced on April 29, 2002[2] as a cost-cutting measure in accordance with the IMCE's recommendations.
The Core Complete concept was roundly criticized by many experts at the time since a majority of development work on the X-38 had been completed. The prototype space vehicle was approximately 90% complete at the time it was cancelled.[citation needed]
Legacy and vehicle redeployment
The X-38 V-132 is now[
As of October 2015[update] the 90% complete X-38 V-201, having been moved out of Building 220 at Johnson Space Center, is now sitting outside Building 49 wrapped in construction webbing at Johnson Space Center.[citation needed]
As of January 2024[update], the X-38 V-131R is on loan from NASA to the
Specifications
Data from [8]
General characteristics
- Crew: Seven astronauts
- Length: 30 ft (9.1 m)
- Wingspan: 14 ft 6 in (4.42 m)
- Height: 7 ft 3 in (2.22 m)
- Empty weight: 23,500 lb (10,659 kg)
- Gross weight: 25,000 lb (11,340 kg)
See also
Related development
- Martin-Marietta X-24
- HiMAT Remotely Piloted Vehicle
Aircraft of comparable role, configuration, and era
Notes
- ^ "NASA X-38 Project Description". NASA. Retrieved 2015-04-18.
- ^ a b "X-38". Federation of American Scientists. Retrieved 2006-09-20.
- ^ Marcus Lindroos. "Nasa acrv". Encyclopedia Astronautica. Archived from the original on 2006-12-10. Retrieved 2007-01-05.
- ^ Carreau, Mark (June 9, 2002). "X-38 project's cancellation irks NASA, partners". chron.com. Houston Chronicle. Retrieved 2015-10-06.
a serious illness or injury to a station astronaut; a serious fire or collision with space debris; or grounding of the space shuttle so that it could not deliver life-sustaining supplies.
- ^ "NASA - Current Research Projects - X-38 CRV". NASA. Retrieved 2006-09-13.
- ^ "Robert Meyerson | 32nd Space Symposium". 2016.spacesymposium.org. Retrieved 2021-05-19.
- ^ "X-38 Team Successfully Flies Largest Parafoil Parachute in History". NASA. Archived from the original on 2003-08-19. Retrieved 2010-12-19.
- ^ "The X-38 Low-Cost High-Tech Space Rescue | PDF | Lifting Body | Space Shuttle".
References
- Catchpole, John E. (2008). The International Space Station: Building for the Future. Praxis. p. 79. ISBN 978-0387781440.
- "NASA Dryden Fact Sheets". NASA. Retrieved 2006-09-13.
- "NASA - Current Research Projects - X-38 CRV". NASA. Retrieved 2006-09-13.
- "X38/CRV FDIR". NASA's Smart Systems Research Lab. Archived from the original on 2006-09-29. Retrieved 2006-09-13.
- "Crew Return Vehicle (CRV)". ESA. Retrieved 2006-09-14.