DPFにおける地球重力場の影響 安東 正樹 Department of Physics, the University of Tokyo Tsubono Group Seminar (23 July, 2008)
Gravity-gradient noise Global gravity field model Cut-off at 0. 03 Hz: originates in the model resolution Unknown at higher frequency This will not be a problem: Satellite velocity of 5 km/sec higher-order contribution will be negligible Estimate the noise spectrum order of ~(Re/r) n Assume 2% vertical-horizontal coupling Observe gravity field with higher resolution? Public data obtained by GRACE Up to 150 th-order in spherical harmonics Tsubono Group Seminar (23 July, 2008) 3
DPF ペイロード Upper half of the satellite Weight : ~100 kg Size : ~90 cm cube Laser source Nd: YAG laser (1064 nm) Power : 25 m. W Freq. stab. by reference cavity Drag-free control Local sensor signal Feedback to mission thrusters Fabry-Perot interferometer Finesse : 100 Length : 30 cm Test mass : 1 kg Signal extraction by PDH Tsubono Group Seminar (23 July, 2008) 13