On March 12th, 1998 the first free-flight of the X-38 (CRV) was accomplished. The X-38 was developed from the Martin Marietta X-24, a lifting body design pioneered by Dryden Flight Research Center in the 1960s and 1970s. The goal of the X-38 project was to provide a means for astronauts on the ISS a way to return to earth in the event of an emergency.
In 1995, development of the X-38 began. The project was managed by NASA Johnson Space Center and in early 1996 a contract was awarded to Scaled Composites for the construction of three full-scale atmospheric test airframes. They were built of materials such as fiberglass and graphite epoxy and strengthened with steel and aluminum at stress points. Three prototype X-38s used in the atmospheric flight testing program were 24.5 feet long, 11.6 feet wide and 8.4 feet high. Vehicle weights ranged from 15,000 pounds to about 25,000 pounds. They were approximately 80 percent of the planned size of the CRV. In September 1996, the first airframe was delivered to Johnson Space Center for testing.
In July of 1997, several captive-carry flights were undertaken to study the X-38’s aerodynamics while attached to the wing pylon of a B-52. Two free-flights were performed in March of 1998 and February of 1999 to study launch characteristics and also to assess the operation of the parachute. Testing continued until the X-38 program was cancelled on April 29th, 2002.