The selene project and the following lunar mission

Abstract

The SELENE (SELenological and Engineering Explorer) project is the NASDA's first joint lunar mission with ISAS which is planned to be launched in 2003 by Japanese H-IIA launch vehicle. The major objectives of the SELENE project are researches of lunar science and feasibility of lunar utilization by the global mapping from a low lunar orbit, as well as the development of key technologies for the lunar exploration such as the soft landing technology. SELENE consists of 2 satellites, a main polar orbiter with a propulsion/landing module and a small relay satellite. The main orbiter will be inserted into 100 km altitude polar circular orbit for its 1-year mapping mission. About a dozen of scientific instruments on the main orbiter are used for the extensive global mapping of lunar surface and lunar-terrestrial science. Far-side gravimetry is implemented by the relay satellite to measure 4 way range rate from the ground station to the main orbiter. After its 1-year observation from the low lunar orbit, the propulsion/landing module will be separated to implement the soft landing experiment to verify its technology. After its successful landing on the nearside of the moon, lunar gravimetry and selenodecy in high resolution will be implemented by means of differential VLBI method with a radio source instrument on the propulsion/landing module and the relay satellite. Now, the next Lunar mission, called SELENE-2nd is being studied in the same framework of ISAS/NASDA joint program. SELENE-2nd will perform lunar science on the surface of the Moon, which will provide the more detailed data to solve the origin and evolution of the Moon in conjunction with the data obtained by SELENE. SELENE-2nd will also give the opportunity for the development of key technologies such as survival technology and traverse technology necessary for the future activities on the Moon. This paper describes the current status of SELENE including the result of phase-B study, and introduce one of the options of SELENE-2nd concept.