The First Precise Global Gravity and Topography of the Moon by KAGUYA (SELENE)

Abstract

Using 4-way Doppler tracking with relay satellite OKINA, KAGUYA obtained the first precise gravity field of the lunar farside. Multi-frequency differential Very Long Baseline Interferometry (VLBI) observation using OKINA and OUNA improved the accuracy of gravity, through precise determination of OKINA's orbit. The current gravity model is SGM100i involving VLBI data. Laser altimeter (LALT) on board KAGUYA obtained the first precise global topography of the Moon with range accuracy of 5m. The correlation of spherical harmonics coefficients between gravity and topography become higher than that of the previous model. Gravity signatures of far-side impact basins are mostly explained by topography except for the central high. Combined with topography data, we estimate Bouguer anomaly and the crustal thickness variation of the Moon.