IMPROVED FLIGHT-TYPE ARCJET POWER CONDITIONER

ALTHOUGH SEVERAL RESEARCH EFFORTS ARE CONCENTRATING ON DEVELOPMENT OF ARCJET THRUSTERS FOR ELECTRIC PROPULSION APPLICATIONS, RELATIVELY LITTLE WORK IS ADDRESSING THE POWER SUPPLY ELECTRONICS REQUIRED TO OPERATE THESE THRUSTERS. EXPERIMENTS ON ARCJETS TYPICALLY HAVE USED LARGE LABORATORY POWER SUPPLIES, WHICH ARE INAPPROPRIATE FOR ANY SPACESYSTEM DESIGN. THE TYPE OF POWER CONDITIONING UNIT NEEDED FOR ARCJET OPERATION MUST BE CAPABLE OF CONTROLLING THE CURRENT INTO THE UNSTABLECURRENT-VOLTAGE CHARACTERISTIC OF AN ARC, WHICH HAS NEGATIVE RESISTANCE. AN IMPROVED FLIGHT-TYPE ARCJET POWER CONDITIONER, WHICH IS BASED ON A MULTI-PHASE BUCK REGULATOR CONCEPT, IS BEING DESIGNED FOR CONTROL OF 30 KWE ARCJET THRUSTERS. HIGH FREQUENCY SWITCHING OF THE CURRENTS THROUGH A GROUP OF PARALLEL INDUCTORS CONTROLS THE CURRENT INTO THE ARCJET LOAD. THE DESIGN INCORPORATES SEVERAL INNOVATIONS FOR HIGH EFFICIENCY AND COMPACT, LIGHTWEIGHT PACKAGING. AREDUCED POWER BREADBOARD UNIT IS BEING BUILT AND TESTED USING ARCJETS UNDER DEVELOPMENT. A FLIGHT-TYPE DESIGN, WHICH INCORPORATES THE ADVANCED FEATURES OF THE BREADBOARD UNIT, IS ALSO BEING PREPARED. IF THE BREADBOARD SUCCESSFULLY DEMONSTRATES OPERATION BY REDUCED POWER AND VERIFIES THE POTENTIAL FOR SCALE-UP TO FULL POWER OPERATION, THE FLIGHT DESIGN WOULD BE CONSTRUCTED AND OPERATED DURING A LATER PHASE.