Premix Gas Injector and Thermally Choked Chamber

ORBITEC proposes to design and develop a small commercial thruster which combines innovative concepts to produce a scalable, high response, precisely controlled, low cost, highly reliable family of thrusters for altitude control, orbit change, and maneuvering applications in space. The key concepts involved are: premixing the propellants prior to injection, and a thermally choked chamber which allows using a chamberless throat and skirt for the combustion/expansion process. The problem areas on small thrusters are: (1) inefficient long-term storage of propellants which has led to common use of storable propellants in spite of their lower performance and the contamination produced by the exhaust plume; (2) chamber cooling because of the high surface to volume ratio of the chamber, which has resulted in resorting to very high rates of film cooling which reduces performance further and increases plume contamination; (3) difficulty with injection and mixing because of the small orifice sizes, and effects of the nearby wall, which has led to problems of chamber wall streaking and pitting, reduced performance and shortened chamber life; and (4) precision of start and stop thrust curves and precision of impulse for short pulses, which makes the controllability of space vehicles more complex, and is particularly severe when doking maneuvers are involved. The innovations proposed define a thruster which effectively resolves many of these problems in a single compact, low-cost assembly.