Electromagnetic emission experiences using electric propulsion systems

Abstract

Introduction A electric propulsion systems become ready to integrate with spacecraft systems, the characterization of propulsion system radiated emissions is of significant interest. This paper briefly summarizes communications and dynamic electromagnetic experiences using electromagnetic, electrostatic, and electrothermal propulsion systems. Electromagnetic radiated emission results from ground tests and flight experiences are presented, with particular attention paid to the performance of spacecraft subsystems and payloads during thruster operations. The impacts to transmission of radio frequency signals through plasma plumes are also reviewed. Over the last 30 years, more than 60 spacecraft were flown using electric propulsion systems for drag makeup, stationkeeping, and The major flight-qualified thruster systems are ablative pulsed plasma thrusters (PPT), ion thrusters, magnetoplasmadynamic (MPD) thrusters, and resistojets. Average power dedicated to the propulsion system ranged from about 3 W for early pulsed plasma devices to about 1 kW for each (space electric rocket test) SERT-II ion (See Table 1.) Table 1 does not characterize all electric propulsion flights; only publications that refer to thrusters electromagnetic (EM) emissions or RF interactions with plumes were considered in this survey. Except for some resistojet systems, most electric propulsion systems require power processing equipment to tailor the battery or solar array power to that of the thruster. The thruster/power processor produces an electromagnetic environment that could potentially impact spacecraft systems such as communications, guidance, navigation and control, payloads, and experiments. The EM environments may have permanent and varying magnetic fields along with radio frequency and conducted electrical emissions. Prior to flight, electromagnetic interference (EMI) measurements must be made, and hardware must be immunized or the level of EM I reduced to satisfy the compatibility requirements. Previous papers have surveyed the particle and field interactions using ion thrusters and MPD arcjets. This paper will review radio frequency interference (RFI) component test specifications, results of spacecraft integration tests, and radiated emissions from flight systems using electromagnetic, ion, and electrothermal thrusters. Spacecraft schematics and ground test configurations will be discussed, general test procedures will be synopsized, and spacecraft integration test results will be reported. Most of the EM emission results were obtained from four flights using ablative pulsed plasma thrusters, six ion propulsion flights, and three flights using electromagnetic devices (see Table 1). Only published or publicly available information was used in compiling this report. Most of the electric propulsion work pertaining to EM emissions characterization was performed in the U.S., Japan, USSR, West Germany, and China.