Spacecraft attitude and velocity control thruster system

In a space craft rocket propulsion system, an attitude and velocity control propulsion system comprising:

• monopropellent thruster means, said mono propellant thruster means having a fuel inlet for producing first level thrust in response to receiving propellant fuel at said fuel inlet;
• bipropellant secondary combustion augmented thruster means, said bipropellant secondary combustion augmented thruster means including a fuel inlet and an oxidizer inlet for producing a second level thrust responsive to receiving both fuel and oxidizer at said respective fuel and oxidizer inlets and for alternatively producing a first level thrust responsive to only receiving fuel at said fuel inlet said second level thrust being at least fifty per cent greater than said first level thrust;
• liquid fuel tank means for storing fuel in liquid form;
• liquid oxidizer tank means of storing oxidizer in liquid form;
• first valve means for coupling fuel from said liquid fuel tank means to said inlet of said monopropellent thruster means;
• second valve means for coupling fuel from said liquid fuel tank means to said fuel inlet of said bipropellant secondary combustion augmented thruster means;
• third valve means for coupling oxidizer from said liquid oxidizer tank means to said oxidizer inlet of said bipropellant secondary combustion augmented thruster means;
• and
• controller means for operating said first valve means to produce first level thrust to effect a change of space craft attitude and for alternatively operating said second and third valve means for producing second level thrust to effect a change of space craft velocity.

Rocket apparatus for producing a pulsating thrust comprising in combination:

• bipropellant rocket engine means for producing thrust, said rocket engine means having a fuel inlet and an oxidizer inlet;
• an engine controller;
• fuel inlet valve means connected to said fuel inlet for controlling fuel flow into said bipropellant rocket engine means under command of said engine controller;
• oxidizer inlet valve means connected to said oxidizer inlet for controlling oxidizer flow into said bipropellant SCAT thruster means under command of said engine controller;
• said fuel inlet valve means comprising:
• first and second fuel inlet valves connected in series;
• said oxidizer inlet valve means comprising:
• first and second oxidizer inlet valves connected in series;
• flow limiting bypass orifice connected in shunt of said first inlet fuel valve means to permit a limited flow of fuel to said second fuel inlet valve when said first fuel inlet valve is closed;
• and
• flow limiting oxidizer bypass orifice connected in shunt of said first inlet oxidizer valve means to permit a limited flow of fuel to said second oxidizer inlet valve when said first oxidizer inlet valve is closed;
• said controller including means for operating said second fuel inlet valve to close said second fuel inlet valve and for simultaneously periodically operating said first fuel inlet valve to periodically close and open said first fuel inlet valve;
• and means for operating said second oxidizer inlet valve to close said second oxidizer inlet valve and for simultaneously periodically operating said first oxidizer inlet valve in synchronism with said first fuel inlet valve to periodically close and open said first oxidizer inlet valve, whereby said bipropellant rocket engine produces thrust that alternates between two thrust levels.