A Study on EMC Test Methods for ESD-Induced Conducted Noise through Space Structures

In orbiting spacecraft, electrical units may malfunction due to noise caused by electrostatic discharge (ESD) on the surface of the spacecraft. As a noise propagation model that leads to malfunctions, it is well known that there is a mode in which electromagnetic noise emitted from the discharge source propagates through free space and irradiates the electrical unit. In addition to this, there is a mode in which the current originating from the discharge propagates and flows across the surface of the spacecraft structure, is induced in the power supply harness or signal harness, and enters the electrical unit as conducted noise. On-orbit failures due to ESD-induced conductive noise have occurred on Japanese spacecraft, but although EMC test methods for this mode have been standardized by the European Space Agency (ESA), they are not easy to apply elsewhere because they require special test equipment that is difficult to obtain. In order to address this issue, we are investigating an EMC test method using equipment that is expected to be available in standard EMC Test laboratories. In this paper, we will show results of our investigation about new test method for noise propagation through spacecraft structure due to ESD.