Ground Chamber Measurements of the Electromagnetic Emissions from the Hayabusa Ion Engine

Abstract

DOI: 10.2514/1.19473 Radiated electric field emissions from the prototype model of the ion engine system of the asteroid explorer Hayabusa (MUSES-C) were measured in approximate accordance to MIL-STD-461C. The typical noise level exceeded the narrowband specification at frequencies less than 5 MHz. The microwave discharge neutralizer generates broadband noise and narrowband oscillations that have a fundamental frequency of about 160 kHz and are accompanied by its harmonics up to the fifth. Leakage of 4.25 GHz microwaves for plasma production and its second harmonic were 65 dB and 35 dB above specifications, respectively. The X-band receiver onboard Hayabusa measured the noise from the ion engine system at the uplink frequency of 7.16 GHz through a horn antenna. This susceptibility test showed that the microwave discharge ion thruster is unlikely to interfere with deep space microwave communication. Nomenclature d = neutralizer orifice diameter ID = electron emission current of the neutralizer l = anode distance from the neutralizer _ m = xenon flow rate P� = microwave power for plasma discharge of the neutralizer VD = voltage between the neutralizer and the anode in diode mode operation