KMAG: KPLO Magnetometer Payload

Abstract

Kplo-MAGnetometer (KMAG) is one of the scientific instruments of Korea Pathfinder Lunar Orbiter (KPLO) set to be launched in 2022. Its objectives are magnetic field investigation and technical demonstration near the surface of the Moon. Specifically, it will investigate the lithospheric magnetism of the Moon and measure the electromagnetic wave properties near the lunar surface. It consists of three fluxgate magnetometers on a 1.2 m long boom, which is relatively shorter than the boom used in other missions. The three magnetometers are included for scientific measurements, redundancy checks, and multi-sensor technical investigation. The magnetometers and an inner Anisotropic Magneto-Resistive sensor perform simultaneous sampling to correct for the magnetic field interference caused by the spacecraft. The fully integrated flight model assembly showed that the magnetometer noise level was less than 30 pT Hz−1/2 at 1 Hz and stability was within ±0.2 nT at the 10 Hz sampling rate. This paper describes the configuration and performance of the KMAG using the multi-sensing method. KPLO, THEMIS-ARTEMIS spacecraft, and Commercial Lunar Payload Service modules will be in their operational phase simultaneously. Therefore, the KMAG will be able to contribute to multi-site in-situ measurements of the lunar magnetic field. We expect that the KMAG will provide an up-to-date lunar observation data set and an opportunity to perform the multi-sensor observation.

Correction of Spacecraft Magnetic Field Noise: Initial Korean Pathfinder Lunar Orbiter MAGnetometer Observation in Solar Wind

“…However, we confirmed that an unwanted spacecraft interference field existed in the observation data, as we expected. To identify a spacecraft-generated magnetic field, we used the dataset from the three magnetometers installed inside the boom and a magnetoresistance sensor inside the spacecraft body [14]. In general, a spacecraft-generated magnetic field is reduced according to the distance from the center of the spacecraft, and the dependence on distance is also confirmed under the condition of multiple magnetic sources inside the spacecraft, as suggested by Park et al [15].…”

Korea Pathfinder Lunar Orbiter Magnetometer Instrument and Initial Data Processing

“…KMAG is the first magnetometer instrument developed in South Korea for space exploration beyond the Earth, and it was designed to carry out only the most basic functions. The instrument specifications and performance are described in a previous paper (Lee et al 2021). In the design stage, the magnetic cleanliness requirement was insufficient to obtain clean observation, and the boom length was also relatively short because of the limitations of mass and volume (Park et al 2022).…”

Overview of the Flight Dynamics Subsystem for Korea Pathfinder Lunar Orbiter Mission

“…The KGRS will investigate the chemical composition of the lunar surface materials by mapping the spatial distribution of gamma-ray energy, which ranges from 10 keV to 10 MeV [5]. The magnetic strength of the lunar surface (up to~100 km) will be measured via the KMAG with ultrasensitive sensors [6]. The ShadowCam will take the images of the permanently shadowed regions near the lunar polar regions to search for evidence of water ice deposits.…”