Cobra (original) (raw)

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Cobra

Cobra

Pratt and Whitney LOx/LH2 rocket engine. Design 2003. Proposed as a long-life, moderate-to high-thrust, reusable booster engine that incorporated a safe, low-cost, low-risk, LH2/LOX single burner, using a fuel-rich, staged combustion cycle.

Status: Design 2003. Date: 2003. Thrust: 4,500.00 kN (1,011,600 lbf). Gross mass: 10 kg (23 lb). Unfuelled mass: 3,600 kg (7,900 lb). Height: 0.95 m (3.11 ft). Diameter: 0.10 m (0.32 ft). Span: 0.48 m (1.57 ft).

In 2003 Pratt and Whitney and Aerojet teamed to provide a wide range of main propulsion options in support of NASA's conceptual second generation, reusable launch vehicles. Pratt and Whitney's experience in reusable rocket turbo-machinery and health and maintenance management systems used for jet engines complemented Aerojet's experience in combustion devices and the integration and production of large propulsion systems for the Titan family.

COBRA was proposed as a long-life, moderate-to high-thrust, reusable booster engine that incorporated a safe, low-cost, low-risk, LH2/LOX single burner, using a fuel-rich, staged combustion cycle. Mature, flight proven Space Shuttle Main Engine alternate turbopumps reduced technical, schedule, and programmatic risk while at the same time meeting safety and reliability goals.

Features of the engine included:

Single pre-burner, fuel-rich staged combustion cycle
Double containment, failsafe powerhead, hot gas system
Incorporated flight-certified SSME Block II turbopumps
Long-life, robust, milled-channel nozzle construction eliminated hot side weld joints
Smooth start transients avoided life-limiting thermal stress
Blanch-shielded, formed-platelet liner technology reduced hot wall stress
Turbine inlet temperature reduced 500 deg F relative to the SSME, promoted longer life
Integrated engine controls and health management system enhanced safety and maintainability
Low development cost/risk based on use of flight-qualified hardware and mature technologies
Thrust (vac): 200,000-1,000,000 lbf
Dry Weight (at 600k thrust): 8,000 lbm
Specific impulse (vac): 455 sec
Cycle: Staged combustion
Propellants: Liquid hydrogen / liquid oxygen
Mixture ratio: 5.5:1 to 6.5:1
Shutdown reliability: 0.9995
Catastrophic reliability: 0.999995
Mission life: > 100 missions
Time between overhauls: > 50 missions
Scheduled maintenance per flight: < 100 man-hours
Turnaround between flights: < 16 hours An engine that could meet these specifications would be what the SSME was originally designed to be. Whether this was technically possible was another matter�

Engine: 3,600 kg (7,900 lb). Oxidizer to Fuel Ratio: 6.

Subtopics

PW 1000000 lb LH2 Pratt and Whitney LOx/LH2 rocket engine. Study 1988. Part of launch vehicle proposed by Martin as alternative to NLS. All figures estimated based on 1,000,000 lb thrust single engine.

Country: USA. Propellants: Lox/LH2. Agency: Pratt and Whitney.

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