In-orbit calibration of the lunar magnetometer onboard SELENE (KAGUYA)

Abstract

The high-sensitivity fluxgate Lunar MAGnetometer (LMAG) is mounted on SELENE (KAGUYA) to investigate the near-surface electromagnetic environment and the evolution of the Moon through magnetic field observation. To avoid possible electromagnetic interferences, a triaxial fluxgate sensor (MGF-S) is installed at the far end of a 12-m-long mast. It is critical for the accurate observation to monitor MGF-S alignment in orbit, and thus we have calibrated the sensor alignment by measuring the known magnetic fields generated by the sensor alignment monitor coil (SAM-C) wound onto the mast canister. In-orbit calibration of the MGF-S alignment was performed twice each revolution during the initial check-out phase of the satellite. It is concluded that there is no systematic difference in the sensor alignment between the day-side and night-side. Applying a new technique based on the Davis-Smith method to the observed magnetic field data when KAGUYA was exposed to the solar wind, a zero offset of each axis was quickly and stably determined every month. As a result, LMAG has been calibrated with an accuracy that is sufficient for detection of the lunar magnetic anomaly at an altitude of 100 km and for high-resolution electron reflectometry.

Statistical analysis of monochromatic whistler waves near the Moon detected by Kaguya

“…We use 32 Hz time series of the magnetic field data set obtained by the Lunar Magnetometer (LMAG) on board Kaguya, which has a triaxial ringcore type fluxgate sensor . From the ground and in-orbit calibrations (Shimizu et al, 2008;Takahashi et al, 2009), and the electromagnetic compatibility conditions , the noise level is estimated to be less than 0.1 nT. We applied the fast Fourier transformation (FFT) to every 16 s time interval to obtain the wave spectra of 0.125-16 Hz.…”

Non-monochromatic whistler waves detected by Kaguya on the dayside surface of the moon

“…The magnetic eld data used in this study were obtained by MAP-LMAG magnetometer (Shimizu et al, 2008;Takahashi et al, 2009) onboard Kaguya on its orbit encircling the moon at an altitude of 100 km. when the moon was in the solar wind.…”

Low energy particle spectrometer for 3-axis stabilized spacecraft

“…Figure 8 shows a functional block diagram of MAP-PACE ASKY-ESA sensors on Kaguya. MAP is composed of two subsystems MAP-PACE (Saito et al, 2008a and MAP-LMAG (Lunar MAGnetometer) (Shimizu et al, 2008;Takahashi et al, 2009;Tsunakawa et al, 2010). In order to minimize the mass and power, the control electronics for the MAP-PACE sensors and MAP-LMAG sensors Figure 9 shows a more detailed block diagram of the analyzer head part of MAP-PACE-ESA-S2 that includes ASKY-ESA shown in Fig.…”