NASA X-38

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X-38 descending
X-38 landing on a paraglider

X-38 is the name of a rescue system that should enable the evacuation of the International Space Station (ISS) in an emergency . It consisted of a non-propelled aerodynamic float and should be able to return to earth automatically. The X-38 is closely associated with the designation Crew Return Vehicle (CRV). However, this term is also generally used for spaceships that are held in readiness in the event of an evacuation.

Until the planned implementation of this project, the Soyuz space station was intended to be permanently available rescue options. Since the project was canceled in 2002 and other spaceship developments were also discontinued or suffered from very long delays, this situation remained in the episode.

concept

The plans in the 1990s envisaged bringing the glider to the space station with a space shuttle and leaving it permanently docked there for up to 3 years. In an emergency, the crew would have boarded the X-38, disconnected from the ISS and left orbit. The glider, equipped with a heat shield , would have entered the earth's atmosphere and would have been slowed down by air resistance . In the near-earth layers of air, a paraglider that had been deployed in stages would have enabled the glider and his crew to land safely and softly on the mainland as well. Normally this landing would have taken place automatically, since it was expected that injured crew members would have to be returned.

X-38 was intended purely as a lifeboat and, in contrast to the full-fledged space shuttle NASA HL-20 previously designed by NASA, should not have an autonomous drive, but only control functions through a nitrogen-operated nozzle system and a pair of stern control flaps, which because of the high temperature load when re-entering, as well as other heat shield components (nose cap, wing leading edges), consist entirely of fiber-reinforced ceramic . A drive module with eight nozzles was provided at the stern. It was supposed to move the X-38 away from the space station and provide the braking energy necessary for re-entry. Then it should be blasted off and burn up.

The life support system was designed for seven hours.

For the docking of the X-38 to the space station, the coupling adapter of the low impact docking system was specially developed and also tested as a prototype. The docking adapter would have been on top of the fuselage.

As a model for the development of the X-38 project was X-24A of the United States Air Force / NASA included. The special construction u. a. of the X-38 is called lifting body (dynamic buoyancy body).

European share

Logos on the prototype after the conversion to the V-131 R, Evergreen Aviation & Space Museum 2011
The rear control flaps of the X-38 were made in Germany from C / SiC composite ceramics

The European part of the development consisted, among other things, in the construction of the rear fuselage structure according to the specifications of NASA, the tail structure, rudder, nose cone, flaps on the fuselage, work on aerodynamics, landing gear (runners), seats, development of the docking adapter, cockpit displays and the Avionics. The main contractual partners of ESA were MAN Technologie / Germany and Alenia / Italy, a total of 22 companies from eight countries were involved.

The navigation and control software for the paraglider landing came from ESA and was adapted by NASA, the associated control system was built by Astrium .

On the prototype V-131 R (R = reworked), in addition to the NASA logo, the logos of the ESA and the German Aerospace Center were attached.

During development, the Ariane 5 was under discussion for the launch of a further developed variant of the spacecraft.

Prototypes and flight tests

X-38 on a test flight shortly after being dropped from a B-52 carrier aircraft
Three-sided view V-131

The prototypes, which are about 80% smaller than the planned final model, were built by Scaled Composites . Another full-size prototype built at the Johnson Space Center was supposed to become the first prototype for a flight into space. It was 90% completed. The paraglider system was developed by the US Army. The advancement that took place during the X-38 program also flowed back into military applications.

  • V-131: 80% of the original size; Flight attempts on the B-52 from July 1997, then 2 attempts to drop it; afterwards conversion to V-131R
  • V-131R (rebuild) was created in summer 2000 after revising the outer contour from V-131; Drop attempts
  • V-132: prototype, 80% of the original size; Test flights in March and July 1999 and on March 30, 2000
  • V-201: first prototype, full size; should be transported into space; 90% completed; no attempts to fly

The first flight took place on March 12, 1998. The B-52 that brought the prototypes into the air had also been used to launch the X-15 .

The structural concept of a metallic skeleton with only partially load-bearing planking turned out to be insufficiently efficient, which led to multiple adjustments to the mass of the vehicle and, as a result, to iterations on the paraglider and thermal protection.

After seven flights, the last flight took place on December 13, 2001.

In the course of testing, the world's largest paraglider at that time was used.

End of the project

X-38 at the ISS (computer graphics)

The end of the development of the X-38 came in March 2002 in the course of savings measures after various budgets of the ISS were exceeded. In addition to the X-38, several modules of the ISS were also affected. Originally, the cost of the X-38 project was set at $ 700 million; a CRV capsule development was estimated at $ 2 billion.

The elimination of the crew return vehicle meant that the crew size of the ISS was limited to six space travelers , as only a maximum of two Soyuz spaceships (for three people each) can be docked on the ISS. With an X-38 based CRV, up to seven people could have been evacuated.

One of the X-38 prototypes is on display at the Strategic Air and Space Museum in Ashland, Nebraska.

The concept of the dynamic buoyancy body was taken up by the company SpaceDev or SNC as part of the NASA COTS , CCDev and CRS program and implemented in the development of the Dream Chaser space glider . For this spaceship, ESA is developing and building the IBDM coupling adapter started with the X-38.

See also

Web links

Commons : X-38  - collection of pictures, videos and audio files

Individual evidence

  1. ↑ X-38 daviddarling.info, accessed 28 June 2011
  2. ↑ a b c d Crew Return Vehicle (CRV) - Manned Spacecraft to return the crew to Earth in case of emergency. ESA, July 19, 2004, accessed January 6, 2019 .
  3. ↑ a b c d e f g h i j NASA Armstrong Fact Sheet: X-38 Prototype Crew Return Vehicle. February 28, 2014, accessed January 6, 2019 .
  4. ^ Eckart D. Graf: ESA and the ISS Crew Return Vehicle. SpaceRef.com, May 27, 2001, accessed January 29, 2020 .
  5. ↑ a b c Jenny M. Stein, Chris M. Madsen and Alan L. Strahan: An Overview of the Guided Parafoil System Derived from X-38 Experience . Ed .: NASA Johnson Space Center. (English, nasa.gov [PDF; accessed January 8, 2019]).
  6. ↑ X-38. NASA, February 6, 2002, accessed January 7, 2019 .
  7. ↑ Description on history.nasa.gov p. 48 (X-38). (PDF; 1.2 MB) Retrieved April 8, 2013 .
  8. ↑ NASA X-38 team flies largest parafoil parachute in history. February 6, 2000, accessed January 8, 2019 .
  9. ^ The Cutest Little Spaceship that Never Flew universetoday.com
  10. ^ X-38 Crew Return Vehicle Finds New Home nasa.gov, accessed June 25, 2011
  11. ↑ IBDM: The International Berthing Docking Mechanism For Human Missions to Low Earth Orbit and Exploration. 2010, accessed on January 10, 2020 (English, abstract text of IAF publication IAC-10.C2.7.9).
  12. ↑ Europe to invest in Sierra Nevada's Dream Chaser cargo vehicle. SpaceNews.com, January 22, 2016, accessed December 27, 2018 .
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