X-34A

X-34A [NASA]

X-34A [NASA]

The X-34 was originally conceived as a reusable two stage launch vehicle for small orbital payloads, powered by a Russian RD-120 engine. During development, the X-34 was descoped to a hypersonic text vehicle, eliminating the second stage. Orbital (OSC) was selected as a prime contractor. It was to be air-launched by Orbital's L-1011 aircraft and powered by NASA's FASTRAC rocket engine.

The objectives of the X-34 were:

• Readily enable integration of new technologies
• Capable of 25 test flights over a period of one year
• Capable of autonomous flight operations
• Capable of demonstrating safe abort
• Demonstrate technologies throughout flight profile
• Subsonic and hypersonic flight
• Capable of powered flight to at least 250 kft
• Capable of eventually attaining Mach 8
• Demonstrate or be upgradable to advanced RLV technologies
• Incorporate some composite structures (aero, prime airframe and thrust structures)
• Composite propellant tanks and cryo insulation
• Composite lines, ducts, valves
• Advanced operable TPS including leading edge materials
• Advanced low cost avionics (Navstar/INS)
• Rapid low cost flight software development tools
• Integrated vehicle health monitoring
• Capable of attaining average recurring flight cost
• Adaptable as a low Mach number test bed (embedded, attached, or deployed) e.g., RBCC; Plug Nozzle; Pulse detonation wave; dual expansion engines

Three vehicles were to be built, but only one was completed. The X-34 program was cancelled in March 2001 after some captive flight test were made.