Airbreathing engine selection criteria for SSTO propulsion system
Abstract
This paper presents airbreathing engine selection criteria to be applied to the propulsion system of a Single Stage To Orbit (SSTO). To establish the criteria, a relation among three major parameters, i.e., delta-V capability, weight penalty, and effective specific impulse of the engine subsystem, is derived as compared to these parameters of the LH2/LOX rocket engine. The effective specific impulse is a function of the engine I(sub sp) and vehicle thrust-to-drag ratio which is approximated by a function of the vehicle velocity. The weight penalty includes the engine dry weight, cooling subsystem weight. The delta-V capability is defined by the velocity region starting from the minimum operating velocity up to the maximum velocity. The vehicle feasibility is investigated in terms of the structural and propellant weights, which requires an iteration process adjusting the system parameters. The system parameters are computed by iteration based on the Newton-Raphson method. It has been concluded that performance in the higher velocity region is extremely important so that the airbreathing engines are required to operate beyond the velocity equivalent to the rocket engine exhaust velocity (approximately 4500 m/s).
- Publication:
-
Japan Society of Aeronautical Space Sciences Transactions
- Pub Date:
- February 1995
- Bibcode:
- 1995TJSAS..37..239O
- Keywords:
-
- Air Breathing Engines;
- Feasibility Analysis;
- Propulsion System Performance;
- Single Stage To Orbit Vehicles;
- Spacecraft Propulsion;
- Aerodynamic Drag;
- Newton-Raphson Method;
- Propellants;
- Specific Impulse;
- Structural Weight;
- Systems Analysis;
- Thrust;
- Spacecraft Propulsion and Power