The X-38 is an experimental re-entry vehicle designed by NASA to research a possible emergency crew return vehicle (CRV) for the International Space Station (ISS). The 1995–2002 program also developed concepts for a crew return vehicle design that could be modified for other uses, such as a possible joint U.S. and international human spacecraft that could be launched on the European Ariane 5 booster. The program would eventually develop a total of three test prototype flight demonstrators for the proposed Crew Return Vehicle, each having incremental improvements on its predecessor. All three were wingless lifting body vehicles used in drop tests. The X-38 program was canceled in 2002 due to budget cuts.
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 Soyuz TMA vehicle that could be docked to the station at any given time. Later in May 2009 provisions were added for a total of two docked Soyuz vehicles simultaneously and the ISS crew was increased to 6 members. NASA has designed several crew return vehicles over the years with varying levels of detail. 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:
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.
Development In an unusual move for an X-plane, the program involved the European Space Agency and the German Space Agency DLR. It was originally called X-35. The program manager was John Muratore, while the Flight Test Engineer was future NASA astronaut Michael E. Fossum. Rob Meyerson, who later went on to become President of Blue Origin, was an early member of the team. The X-38 design used a wingless lifting body concept originally developed by the U.S. Air Force in the mid-1960s during the X-24 program. R. Dale Reed worked for NASA from 1955-2000 and is considered the Father of the Lifting Body Programs. He met with Muratore (1992-93) and shared his design of the X-24A that he used to present the concept of the X-38 to NASA (Wingless Flight, Chapter 9, pages 186-88). 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 aerodynamic shape of the X-24A. This shape had to be enlarged for the Crew Return Vehicle needs (crew of seven astronauts) and redesigned, especially in the rear part, which became thicker. The X-38 V-131-R was designed at 80 percent of the size of a CRV [24.5 ft (7.5 m) long, 11.6 ft (3.5 m) wide, 8.4 ft (2.6 m) high], 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 drop tests the V-131, V-132 and V-131-R were dropped by a B-52 from altitudes of up to 45,000 ft (13,700 m), gliding at near transonic speeds before deploying a drogue parachute to slow them to 60 miles per hour (97 km/h). The later prototypes had their descent continue under a 7,500-square-foot (700 m2) parafoil wing, the largest ever made. Flight control was mostly autonomous, backed up by a ground-based pilot.
Design
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