Spacecraft Charging for Microsatellite KITSAT-3

Floating potentials for a microsatellite KITSAT-3 are measured with an electron temperature probe. The orbit of the satellite is 730-km altitude, sun-synchronous, with a fixed local time of descending node near 1200 hrs local time. The dimension of the satellite in stowed configuration is approximately 495 × 614 × 852 mm³. The weight of the satellite is 112 kg. In the dayside, a series of attitude maneuvering is performed to rotate the satellite. Significant correlation between the currents generated from the solar arrays and the floating potentials is found. The initial floating potentials that are largely negative (<-10 V) when the solar arrays are directed toward the sun are found to increase up to ∼ -3 V as the rotation of the spacecraft brings the solar arrays nearly perpendicular to the sunlight. The result of the potential variation is verified by a numerical simulation with NASCAP/LEO. The present investigation finds that the floating potentials for a microsatellite KITSAT-3 are determined by the negative charging of the satellite due to the presence of solar arrays.