Between 1993 and 1996, the McDonnell Douglas DC-X, also known as the "Delta Clipper", conducted twelve low-altitude suborbital test launches to verify the configuration and handling of the uncrewed single-stage-to-orbit Delta Clipper design, which was proposed to the United States Department of Defense and the National Aeronautics and Space Administration (NASA) for use as a reuseable launch vehicle. Claimed as the first rocket to conduct a vertical landing on Earth, the DC-X was a one-third scale demonstrator for the proposed operational Delta Clipper vehicle.
After the first three flights Strategic Defense Initiative Organization funding for the test project was cancelled; the remaining test program was conducted by NASA and the Advanced Research Projects Agency. Following the eighth test flight, the vehicle was transferred fully to NASA and the vehicle was modified to DC-XA configuration, also known as "Clipper Graham" after General Daniel O. Graham who had died in 1995 after supporting the Delta Clipper project.
Of the overall test program, ten of the vehicle's launches were fully successful; the fifth test flight was aborted early in the flight following an on-board explosion but the vehicle was successfully recovered. The twelfth and final flight saw one of the vehicle's landing legs fail to extend; on landing, when the vehicle tipped over onto its unsupported corner, a liquid oxygen tank ruptured and exploded, the ensuing fire destroying the modified DC-XA vehicle and ending the program. Despite the loss the program was considered overall to have been a success.
Launch history Flight No. Date and time of takeoff (UTC) Vehicle Launch site Suborbital apogee Outcome Duration Reference 1 18 August 199323:43DC-X White Sands Space Harbor 59 sec Control system and vertical landing capability test. Demonstrated hovering ability and horizontal translation. 2 11 September 199318:12 DC-X White Sands Space Harbor 66 sec Ground effects and ascent-and-landing mode control test. 3 30 September 199317:30 DC-X White Sands Space Harbor 72 sec Aerostability test; vehicle conducted 180° roll. 4 20 June 199415:42 DC-X White Sands Space Harbor 2 min 16 sec First flight with fully loaded propellant tanks and operational radar altimeter. 5 27 June 199415:37 DC-X White Sands Space Harbor 78 sec Flight aborted after hydrogen explosion on launch; autoland capabilities demonstrated. 6 16 May 199516:40 DC-X White Sands Space Harbor 2 min 4 sec Flight envelope expansion test. 7 12 June 199515:38 DC-X White Sands Space Harbor 2 min 12 sec AOA envelope expansion, first reaction control system usage. 8 7 July 199514:02 DC-X White Sands Space Harbor 2 min 4 sec Turnaround maneuver demonstrated; hard landing resulted in damage to the aeroshell. 9 18 May 199615:14 DC-XA White Sands Space Harbor 62 sec First flight following modification to DC-XA configuration; slow landing resulted in aeroshell fire. 10 7 June 199617:15 DC-XA White Sands Space Harbor 64 sec Maximum structural stress test. 11 8 June 199619:17 DC-XA White Sands Space Harbor 2 min 22 sec Demonstration of 26-hour rapid turnaround; altitude and duration record set. 12 31 July 199620:15 DC-XA White Sands Space Harbor 2 min 20 sec Successful maneuvering test; vehicle destroyed on landing when landing strut failed to extend and LOX tank exploded.
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