Laser Ranging and VLBI for the Selene-II Mission

U. Schreiber, N. Kawano, T. Yoshino, H. Kunimori, W. Schlueter

Forschungseinrichtung Satellitengeodaesie,
Fundamentalstation Wettzell
D-93444 Koetzting, Germany

National Astronomical Observatory
Mitaka, Tokyo, Japan

Communications Research Laboratory
2-1, Nukui-Kitamachi 4-chome
Tokyo, Japan

Bundesamt fuer Kartographie und Geodaesie
Fundamentalstation Wettzell
D-93444 Koetzting, Germany

The Selene-II mission can be considered as a first step towards a Japanese observatory on the moon. Selene-II is a follow up on the Selene mission, which is scheduled for launch within the next two years. Selene is already carrying a VLBI experiment. This proposal for an experiment onboard the Selene-II opens the door to a highly improved performance of LLR and a colocation between laser ranging and VLBI both at the location of the observing stations and at the location of the target. It comprises a unique combination for range and direction measurements. The concept of fundamental stations involves the colocation of all relevant techniques of space geodesy in specialised observatories. Using a suitable radio source as well as laser ranging technology on the Selene-II space vehicle, would for the first time colocate VLBI and LLR/SLR on the target end too. This would give precise range and direction information to the Selene-II target on the moon. It can be expected that this greatly enhances the orbit analysis of the earth-moon system, lunar sciences and relativity. Finally, the proposed use of one-way range measurements to the Selene-II will greatly increase the slr data yield for a lunar target.