A vehicle, such as a missile, with a pilot valve system controls the vehicle's thrust valves despite a hostile propellant gas environment. The pilot valve system can have one or more pilot valves. Using refractory elements, the pilot valve ball reciprocates between a supply seat and a vent seat which is subject to the filtered inflow of propellant thrust gases. When open, the pilot valve allows the stray thrust gas to communicate to a control chamber which closes a poppet against a valve seat in the nozzle. When an associated solenoid closes the pilot valve by pushing the pilot valve ball against the supply seat, the control chamber is vented to ambient. The poppet may then travel into the cylinder bore and the nozzle is opened to exhaust propellant gases and exert lateral thrust on the vehicle. Certain nozzle thrust geometries provide useful vehicle guidance.