Flight Research of an Aerospike Nozzle Using High Power Solid Rockets

Flight research has been conducted on an aerospike rocket nozzle using high power solid rockets. Two aerospike rockets and one conventional rocket were flown successfully to supersonic speeds, providing the first known set of transonic flight performance data for aerospike rockets. This paper describes the rockets, solid rocket motors, nozzles, and rocket instrumentation system. Flight test results are also discussed and compared with ground test results. Flight data show that all of the rockets successfully reached supersonic speeds with a maximum Mach number of 1.6 and a peak pressure altitude of nearly 30,000 ft. The aerospike nozzle efficiency was determined to be 0.96 from computational fluid dynamics (CFD) analysis. The rocket chamber pressures and thrusts of the aerospike rocket motors were lower than the conventional rocket motors. Because the same propellant formulation was used in all of the rocket motors, the discrepancy in pressure and thrust was most likely caused by a larger actual aerospike nozzle throat area than the designed throat area. Potential causes for the larger aerospike nozzle throat area are also discussed.