Nonequilibrium Plasma Effects on Telemetry Considerations for Air-Breathing Hypersonic Vehicle Design

Abstract

During certain hypersonic flight regimes, shock heating of air creates a plasma sheath resulting in telemetry attenuation or blackout. The severity of the signal attenuation is dependent on vehicle configuration, flight trajectory, and transmission frequency. With the promise of air-breathing hypersonic vehicles looming on the horizon, telemetry solutions must be found to address safety considerations for flight testing (i.e., flight termination and/or catastrophe analysis). This attenuation phenomena is investigated with a focus on the nonequilibrium plasma sheath properties (electron concentration, plasma frequency, collision frequency, and temperature) for a range of flight conditions and vehicle design considerations. Trajectory and transmission frequency requirements for air-breathing hypersonic vehicle design are then addressed, with comparisons made to both shuttle orbiter and RAM-C II re-entry flights.