DX-XA Flight 2
AKA: Clipper Graham;DC-XA;Delta Clipper Experimental;Delta Clipper-Experimental;SX-1. Status: Retired 1996. First Launch: 1993-08-18. Last Launch: 1995-07-07. Number: 8 . Thrust: 223.00 kN (50,132 lbf). Gross mass: 16,320 kg (35,970 lb). Unfuelled mass: 7,200 kg (15,800 lb). Specific impulse: 373 s. Specific impulse sea level: 316 s. Burn time: 127 s. Height: 14.00 m (45.00 ft). Diameter: 3.05 m (10.00 ft). Span: 4.10 m (13.40 ft). Apogee: 3.00 km (1.80 mi).
The DC-X was an experimental vehicle, 1/3 the size of a planned DC-Y vertical-takeoff/vertical-landing, single stage to orbit prototype. It was not designed as an operational vehicle capable of achieving orbital flight. Its purpose was to test the feasibility of both suborbital and orbital reusable launch vehicles using the VTOVL scheme. The DC-X flew in three test series. The first series ran from August 18 to September 30, 1993, before the initial project funding ran out in late October 1993. Additional funding was provided and a second series was conducted June 1994-July 1995.
The Single Stage Rocket Technology program was an SDIO (Space Defense Initiative Office) program to demonstrate technology readiness for an SSTO vehicle. The SDIO (Strategic Defense Initiative Organization) issued a call for proposal for design studies of a single stage to orbit launch vehicle in August 1990. Six companies responded, four proposing vertical takeoff concepts (McDonnell-Douglas, Rockwell, General Dynamics and Boeing) and two proposing air-launched concepts (Grumman and Third Millennium). A total of $ 12 million in study contracts were awarded to the four companies proposing VTO designs, reflecting SDIO's preference for VTOL concepts studied in an Aerospace Corporation report of the previous year.
Douglas and General Dynamics proposed VTOVL designs. Boeing's final design was an improved version of its HTHL sled- or rail-launched RASV (Reusable Aerodynamic Space Vehicle) powered by uprated Shuttle Main Engines. Rockwell proposed a VTHL vehicle, similar in layout to the Space Shuttle Orbiter, but with an aerospike engine.
Phase II of the program would consist of fabrication of an 'X' subscale demonstrator and design of a 'Y' prototype vehicle. Reflecting SDIO's predilections, Douglas was finally awarded the $60 million Phase II contract The Douglas DC-X was designed primarily to validate the turnaround and landing maneuver required for the company's complex nose-first entry concept (as opposed to the base entry approach of prior VTOVL SSTO designs). This approach would, the company believed, provide a wide cross range, always attractive to the Air Force for operational reasons. In commercial applications nose-first entry would reduce the loads experienced by the crew and passengers to under 2G, compared with 3G for base-first lifting entries. The DC-X was specifically not designed to demonstrate the most critical issue for any practical SSTO: structural mass fraction
Under a 2-year, $58-million Phase II contract, MDSSC and its team-mates were using a rapid prototype approach to design and build a one-third-size experimental vehicle the DC-X, and ground support and operations systems which, through a series of suborbital flights, was to:
The SSRT program consists of three phases. Phase I began in August 1990 and consisted of a $12 million design and risk reduction competition. At that time, the program was focused on multiple single stage-to-orbit concepts which were found to be potentially viable, including vertical take off and landing (VTOL), horizontal takeoff and landing (HTOL) and vertical takeoff and horizontal landing (VTHL) configurations. Following completion of Phase I, a two-year $58 million Phase II contract was competitively awarded to McDonnell Douglas Aerospace, Huntington Beach, Calif., in August 1991. The program was subsequently restructured and focused on building the DC-X and enabling suborbital RLVs for potential use by BMDO. The DC-X design emphasized simplified ground and flight operations, vehicle maintenance, rapid turnaround, and operational characteristics that were also relevant to future orbital vehicles. For example, the highly automated control center for this system was manned by only three people: two for flight operations and one for ground operations and servicing. Successful completion of the DC-X testing in mid 1993 was to form the basis for a Phase III "go/no go" decision by the Department of Defense to develop a follow-on Advanced Technology Demonstrator for support of flight tests and experiments. If a decision was made to proceed with Phase III, the program was to be transferred to another agency.
A systems ground test facility was activated at NASA's White Sands Test Facility (WSTF), and a launch and recovery site at WSMR. The completed DC-X vehicle was tested on a modified propulsion test stand at the WSTF prior to flight testing at WSMR. Maintenance and ground support techniques required for the flight test phase of the program was to be tested, evaluated and refined at WSTF. The aircraft-like flight test program was to began with low altitude hover flights, gradually increasing in altitude and duration, and was to lead to suborbital flights to approximately 5500 m.
Funding was stop-and-go however. By July 1995 the DC-X had completed eight flights in two series, reaching 2500 m. On the eighth flight the aeroshell was cracked in a hard landing.
It was decided to return the vehicle to the Huntington Beach factory for repair and modification to the Delta Clipper Experimental Advanced (DC-XA) configuration. The DC-XA was operated by NASA and the Department of Defense under the Reusable Launch Vehicle program. This had a lightweight graphite-epoxy liquid hydrogen tank and an advanced graphite/aluminum honeycomb intertank built by McDonnell Douglas; an aluminum-lithium liquid oxygen tank built by Energia (Russia); and an improved reaction control system from Aerojet. These improvements reduced dry vehicle mass by 620 kilograms. The flight vehicle, bizarrely renamed by NASA 'Clipper Graham', was tested at White Sands during the summer of 1996, and demonstrated a 26-hour turnaround between its second and third flights, a first for any rocket. After the fourth flight, however, the DC-XA suffered severe damage and the program ended due to lack of funding.
Program Manager for the original SSRT Program was Major Jess Sponable, U.S. Air Force. The prime contractor was McDonnell Douglas Aerospace, Huntington Beach, Calif. The Delta Clipper industrial team consisted of:
The Chief Technical Advisor for the DC-X has noted that reusable launchers, by their nature have intact abort and that do not crash - they have mishaps not failures. Even the several fires and one auto-abort were not flight test failures. In fact, the auto-abort mishap was the first time that a rocket powered unmanned vehicle had ever saved itself from a fiery death. Even the final test which destroyed the vehicle, met all test objectives and had achieved full engine shut-down prior to the one landing gear collapse (due to a very tired, heat exhausted human technician error).
Development Cost $: 58.900 million in 1991 dollars in 1991 dollars. Total Development Built: 1.
Stage Data - DC-X