Electrostatic Discharge Experiment Results on Ground Using Experiment Model of HORYU-IV

HORYU-IV is a 30 cm cubic satellite with an approximate mass of 11 kg. The satellite was successfully launched by a JAXA H-IIA rocket to an orbit of 575 km altitude with a 31° inclination on February 17, 2016. HORYU-IV’s main mission is to capture an electrostatic discharge (ESD) current waveform by an onboard oscilloscope and capture its image by a camera triggered by the oscilloscope. HORYU-IV captured various ESD current waveforms and images in space. Ground-based experiments were carried out to compare the waveforms between the flight results and the ground results. The results of ground-based experiments, compared with the flight results, had lower peak currents and longer durations. This result does not match past ground-based experiments showing that ESD current has lower peaks and longer durations when ambient pressure is lower. Also, the relationship between ESD occurrence location and ESD current waveforms was found through ground-based experiment.