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.[1] 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.[2]
After the first three flights Strategic Defense Initiative Organization funding for the test project was cancelled;[3] the remaining test program was conducted by NASA and the Advanced Research Projects Agency.[4] Following the eighth test flight, the vehicle was transferred fully to NASA and the vehicle was modified to DC-XA configuration,[5] also known as "Clipper Graham" after General Daniel O. Graham who had died in 1995 after supporting the Delta Clipper project.[6]
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.[1]
Launch history
edit| Flight No. | Date and time of takeoff (UTC) | Vehicle | Launch site | Suborbital apogee | Outcome | Duration | Reference |
|---|---|---|---|---|---|---|---|
| 1 | 18 August 1993 23:43 |
DC-X | White Sands Space Harbor | 46 m (151 ft) | Success | 59 sec | [7] |
| Control system and vertical landing capability test.[7] Demonstrated hovering ability and 350 foot (110 m) horizontal translation.[6] | |||||||
| 2 | 11 September 1993 18:12 |
DC-X | White Sands Space Harbor | 92 m (302 ft) | Success | 66 sec | [7] |
| Ground effects and ascent-and-landing mode control test.[7] | |||||||
| 3 | 30 September 1993 17:30 |
DC-X | White Sands Space Harbor | 370 m (1,210 ft) | Success | 72 sec | [7] |
| Aerostability test; vehicle conducted 180° roll.[7] | |||||||
| 4 | 20 June 1994 15:42 |
DC-X | White Sands Space Harbor | 870 m (2,850 ft) | Success | 2 min 16 sec | [7] |
| First flight with fully loaded propellant tanks and operational radar altimeter.[7] | |||||||
| 5 | 27 June 1994 15:37 |
DC-X | White Sands Space Harbor | 790 m (2,590 ft) | Partial failure | 78 sec | [7] |
| Flight aborted after hydrogen explosion on launch; autoland capabilities demonstrated.[7] | |||||||
| 6 | 16 May 1995 16:40 |
DC-X | White Sands Space Harbor | 1.33 km (0.83 mi; 4,400 ft) | Success | 2 min 4 sec | [7] |
| Flight envelope expansion test.[7] | |||||||
| 7 | 12 June 1995 15:38 |
DC-X | White Sands Space Harbor | 1.74 km (1.08 mi; 5,700 ft) | Success | 2 min 12 sec | [7] |
| AOA envelope expansion, first reaction control system usage.[7] | |||||||
| 8 | 7 July 1995 14:02 |
DC-X | White Sands Space Harbor | 2 km (1.2 mi; 6,600 ft) | Success | 2 min 4 sec | [7] |
| Turnaround maneuver demonstrated; hard landing resulted in damage to the aeroshell.[7] | |||||||
| 9 | 18 May 1996 15:14 |
DC-XA | White Sands Space Harbor | 244 m (801 ft) | Success | 62 sec | [7] |
| First flight following modification to DC-XA configuration; slow landing resulted in aeroshell fire.[7] | |||||||
| 10 | 7 June 1996 17:15 |
DC-XA | White Sands Space Harbor | 590 m (1,940 ft) | Success | 64 sec | [7] |
| Maximum structural stress test.[7] | |||||||
| 11 | 8 June 1996 19:17 |
DC-XA | White Sands Space Harbor | 3.14 km (1.95 mi; 10,300 ft) | Success | 2 min 22 sec | [7] |
| Demonstration of 26-hour rapid turnaround; altitude and duration record set.[7] | |||||||
| 12 | 31 July 1996 20:15 |
DC-XA | White Sands Space Harbor | 1.25 km (0.78 mi; 4,100 ft) | Partial success | 2 min 20 sec | [7] |
| Successful maneuvering test; vehicle destroyed on landing when landing strut failed to extend and LOX tank exploded.[7][8] | |||||||
References
edit- ^ a b McLaughlin, Hailey Rose (29 October 2019). "DC-X: The NASA Rocket That Inspired SpaceX and Blue Origin". Discover. Kalmbach Publishing. Archived from the original on 20 November 2020. Retrieved 21 December 2020.
- ^ "Rocket has good test flight". Tampa Bay Times. Tampa. 20 August 1993. Archived from the original on 21 December 2020. Retrieved 21 December 2020.
- ^ Burdick, Alan (7 November 1993). "Pie In The Sky?". The New York Times. New York. pp. 6–46. Archived from the original on 26 May 2015. Retrieved 21 December 2020.
- ^ "Delta Clipper Test Program Off To Flying Start". McDonnell Douglas via NASA. 20 June 1994. Archived from the original on 27 September 2020. Retrieved 21 December 2020.
- ^ "Will The Delta Clipper Scuttle The Shuttle?". Bloomberg. New York. 8 July 1996. Retrieved 21 December 2020.
- ^ a b Lerner, Preston (August 2010). "Black Day at White Sands". Air & Space Magazine. Smithsonian Institution. Archived from the original on 30 September 2020. Retrieved 20 December 2020.
- ^ a b c d e f g h i j k l m n o p q r s t u v w x Sorensen, Kirk (26 December 2012). Andrew J. Butrica (ed.). "The Delta Clipper Experimental: Flight Testing Archive". NASA. Archived from the original on 12 November 2020. Retrieved 20 December 2020.
- ^ Norris, Guy (6 August 1996). "Clipper flight ends in disaster". FlightGlobal. Retrieved 20 December 2020.