date: 2011 November 2 (Wed) 15:30-16:30
room: CPS Conference Room
speaker: Takahiro Iwata (JAXA/ISAS)
organizer: Hiroshi Kimura
title: Studies of Selenodesy and Planetodesy using Space Geodetic Methods; till and after KAGUYA
abstract: Space geodetic methods, which include radiometry, VLBI (Very Long Baseline Interferometry), etc., are key measurement technologies to elucidate inner structure and mass distribution of terrestrial planets. Two-way ranging and ranging rate is a traditional one which has been applied to make gravity field maps for the moon, Venus, and Mars. The orbital determination data from Lunar Orbiter to Lunar Prospector have produced the models of the lunar gravity field. The gravity data above the lunar far side were, however, less accurate than those above the near side because they were observed from higher orbits or estimated from the near side data which were affected with accumulated acceleration by the far side gravity. Hence KAGUYA, OKINA, and OUNA of SELENE mission have remarkably improved the far side gravity distribution by 4-way Doppler measurements and differential VLBI observations.
For post-SELENE missions, combinations of ‘Lunar Laser Ranging (LLR), VLBI, and In-situ Lunar Orientation Measurement (ILOM) using small telescope on the moon’ are proposed. Inverse VLBI is also a new technology to conspicuously ameliorate the measurements of Mars’ rotation variation. In this seminar, I review the results of SELENE and future projects of selenodesy and planetodesy using these space geodetic methods.
keywords: space geodesy, gravity field, rotation variation, SELENE, MELOS