Results of the Critical Design of RSAT/VRAD Mission Instruments on SELENE Sub-satellites Rstar/Vstar for Selenodesy
Four-way Doppler measurements and differential VLBI will be executed by SELENE to obtain highly accurate global mapping and improve the model of lunar gravity. Two small sub-satellites: Relay Satellite (Rstar) and VLBI Radio Satellite (Vstar), which are separated from SELENE Main Orbiter, perform these selenodetic observation using Relay Satellite Transponder (RAST) and VLBI Radio Sources (VRAD). These sub-satellites have no thrusters to control orbits and attitude to yield precise measurements of orbits perturbed by gravity anomaly. Lack of thrusters, however, causes the instability of attitude that interfere the selenodesy observation. The tip off at the separation and the solar radiation pressure torque dominantly affect the attitude, hence, we evaluated them in the critical design phase of the sub-satellite development. Properties of the newly developed release mechanism were obtained by ground tests, and the satellite attitude inclination by disturbances was analyzed. These results show that the design of the sub-satellites has enough properties to produce selenodesy data.
KeywordsSELENE Moon selenodesy gravity RARR VLBI
Unable to display preview. Download preview PDF.
- Hanada H, Iwata T, Kono Y, Matsumoto K, Tsuruta S, Ishikawa T, Asari K, Ping J, Heki K, Kawano N (2002) VRAD Mission: Precise Observation of Orbits of Sub-satellites in SELENE with International VLBI Network, In: Vandenberg NR, Baver KD (eds) Proc. International VLBI Service for Geodesy and Astrometry 2002 General Meeting, NASA/CP-2002-210002, pp 72–76Google Scholar
- Iwata T, Takahashi M, Namiki N, Hanada H, Kawano N, Heki K, Matsumoto K, and Takano T (2001) Mission Instruments for Lunar Gravity Measurements using SELENE Sub-satellites, J Geod Soc Japan 47: 558–563Google Scholar
- Iwata T, Sasaki T, Izumi T, Kono Y, Hanada H, Kawano N, Takano T (2002) Properties of the Release Mechanism of SELENE Relay Satellite and their Influences for the Lunar Gravity Observation, In: Ishii N et al. (eds) Proc. 23rd International Symposium on Space Technology and Science. Sanbi Insatsu, Tokyo, pp 1928–1933Google Scholar
- Kikuchi F, Kono Y, Hanada H, Iwata T, Ono T, Kawano N (2003) Attitude Estimation for a Spin Stabilized Spacecraft from Doppler Shift (in Japanese), Transact IEICE (B) J86-B,6: 959–968Google Scholar
- Matsumoto K, Heki K, Hanada H (2002) Global lunar gravity field recovery from SELENE, In: Vandenberg NR, Baver KD (eds) Proc. International VLBI Service for Geodesy and Astrometry 2002 General Meeting, NASA/CP-2002-210002, pp 381–385Google Scholar
- Noda H, Asari K, Iwata T, Kawano N, Yamamoto Z (2003) Ground-base Verification of Four-way Doppler Measurement for the SELENE Mission, this issueGoogle Scholar
- Ping J, Sengoku A, Nagaoka N, Iwata T, Matsumoto K, Kawano N (2001) How Solar Radiation Pressure Acts on RSAT and VSAT with a Small Evolving Tip-off in SELENE, Earth Planets Space 53: 919–92Google Scholar