The Korean Pathfinder Lunar Orbiter (KPLO)-MAGnetometer (KMAG) consists of three triaxial fluxgate sensors (MAG1, MAG2, and MAG3) that measure the magnetic field around the Moon. The three sensors are mounted in the order MAG3, MAG2, and MAG1 inside a 1.2 m long boom, away from the satellite body. Before it arrived on the Moon, we compared the magnetic field measurements taken by DSCOVR and KPLO in solar wind to verify the measurement performance of the KMAG instrument. We found that there were artificial disturbances in the KMAG measurement data, such as step-like and spike-like disturbances, which were produced by the spacecraft body. To remove spacecraft-generated disturbances, we applied a multi-sensor method, employing the gradiometer technique and principal component analysis, using KMAG magnetic field data, and confirmed the successful elimination of spacecraft-generated disturbances. In the future, the proposed multi-sensor method is expected to clean the magnetic field data measured onboard the KPLO from the lunar orbit.
Keywords: Korean Pathfinder Lunar Orbiter mission; gradiometer technique; initial KMAG observation; spacecraft-generated disturbance.