is still n 2 x70 70 y 70 y nx70 to accommodate the hot gas flow at 3000 u00b0 f the valve clusters 16 and hot gas manifolds 14 are made from high temperature materials such as refractory alloys of columbium tantalum and molybdenum the high oxidation rates of columbium and tantalum when exposed to the oxidizing potential of the hot gases are inhibited by a then 3 mil silicide coating molybdenum and tungsten alloys used where greater strength is required are left uncoated as their oxidation rates are acceptable insulation around the hot components protects the platform 10 and associated electronics from the thermal energy emitted each high pressure nozzle 18 is controlled by a two stage normally closed pneumatic valve having a pilot valve and a piston actuated main stage the pilot valve powers the main stage piston upon command each low thrust nozzle 20 is controlled by a single stage valve similar to the high thrust pilot valve but modified for a slightly higher flow thus by using more efficient propellants at a higher temperature with individually controlled nozzles to provide a variable throat area together with a pressure feedback system to compensate for component tolerances the present invention provides a dual pressure solid propellant control system which saves energy by switching from a high pressure mode to a low pressure mode depending on the particular impulse requirements the saving in energy results in an increased range of several hundred miles over prior art solid propellant control systems although only two pressure modes have been described the pressure is variable within the pressure range 160 550 psi for the described embodiment depending upon p ref and.