Delta Clipper DC-X
-
a reuseable flight test vehicle to validate the rocket-powered vertical take-off and landing (VTOL) concept -

 

The DC-X, short for Delta Clipper or Delta Clipper Experimental, was an unmanned prototype of a reusable single-stage-to-orbit launch vehicle built by McDonnell Douglas in conjunction with the United States Department of Defense's Strategic Defense Initiative Organization (SDIO) from 1991 to 1993. Starting 1994 until 1995, testing continued through funding of the US civil space agency NASA. In 1996, the DC-X technology was completely transferred to NASA, which upgraded the design for improved performance to create the DC-XA.
Built as a 1/3rd scale prototype, the DC-X was never designed to achieve orbital altitudes or velocity, but instead to demonstrate the concept of vertical take off and landing. It would take off vertically like standard rockets, but also land vertically with the nose up. This design used attitude control thrusters and retro rockets to control the descent, allowing the craft to begin atmospheric entry nose-first, but then roll around and touch down on landing struts at its base. The craft could be refueled where it landed, and take off again from exactly the same position.
Construction of the DC-X started in 1991 at McDonnell Douglas' Huntington Beach facility. The aeroshell was custom-constructed by Scaled Composites, but the majority of the spacecraft was built from commercial off-the-shelf parts, including the engines and flight control systems.
NASA agreed to take on the program after the last (of eight) DC-X flight in 1995. In contrast to the original concept of the DC-X demonstrator, NASA applied a series of major upgrades to test new technologies. In particular, the oxygen tank was replaced by a lightweight (alloy 1460 equivalent of alloy 2219) aluminium-lithium alloy tank, and the fuel tank by a newer composite design.The control system was likewise "improved". The upgraded vehicle DC-XA, and resumed flight in 1996. The fourth flight proved to be its last. During testing, one of the LOX tanks had been cracked. When a landing strut failed to extend due to a disconnected hydraulic line, the DC-XA fell over and the tank leaked. The LOX from the leaking tank fed a fire which severely burned the DC-XA, causing such extensive damage that repairs were impractical.

 

 Delta Clipper-Experimental (DC-X) Test Program

Event

Launch Date

 Altitude (m) Duration (sec)

Result

Flight #1

1993

August 18

46 59

Success

Flight #2

September 11

92 66

Flight #3

September 30

370 72

Flight #4

1994

June 20

870 136

Flight #5

June 27

790 78 Flight abort after hydrogen explosion

Flight #6

1995

May 16

1,330 124

Success

Flight #7

June 12

1,740 132

Flihgt #8

July 07

2,500 124

 

 

 Delta Clipper-Experimental Advanced (DC-XA) Test Program

Event

Launch Date

 Altitude (m) Duration (sec)

Result

Flight #1

1996

May 18

244 62

Success

Flight #2

June 07

590 64

Flight #3

June 08

3,140 142

Flight #4

July 31

1,250 140  destroyed after landing
           
         
         
         

 

 

    

   

DC-X Specification

Body height: 12.60 m
Diameter: 4.06 x 4.06 m
Gross mass: 18,900 kilograms
Fuel: LH2/LOX
Fuel mass: 9,800 kilograms
Engines: Four P&W RL-10A-5
Thrust (s.l.): 4 x 55.65 kN;
throttleable from 30% to 100%
Isp (s.l.): 316 sec
+ four thrusters (a 1.96 kN)


      
                                                                                                                                          Avionic



LOX tank


   
LH3 tanks of DC-X and DC-XA

                                  

 

           Thrust structure

 

Interstage


  

One of four used LR-10-5 engines