The MUSES-C, mission description and its status

Abstract The MUSES-C mission is the world's first sample and return attempt to/from the near Earth asteroid Nereus (4660). It is the ISAS (The Institute of Space and Astronautical Science, Ministry of Education) which manages the mission that started in 1996 scheduling to be launched in January of 2002. The mission is built as a kind of technology demonstration, however, it is aiming at not only the in-situ observation but also the touch-down sampling of the surface fragments. The sample collected is returned to the Earth in January of 2006. The mission is a four year journey. The major purpose of it originally consists of the following four subjects: 1) The Ion thruster propulsion performed in interplanetary field as a primary means, 2) Autonomous guidance, navigation and control during the rendezvous and touch down phase, 3) The sample collection mechanism and 4) The hyperbolic reentry capsule with the asteroid sample contained inside it. The current primary objective is extended to carry the joint small rover with NASA/JPL, which is supposed to be placed on the surface and to look into the crater created by the sampling shot of the projectile. The rover is designated as the Small Science Vehicle (SSV) that weighs about 1 kg carrying three kinds of in-situ instruments: 1) A Visible Camera, 2) Near Infra-Red Spectrometer and potentially 3) Alpha-Proton X-ray Spectrometer (APXS) similar to that delivered on the Mars Path Finder. During the fiscal 1998, the spacecraft undergoes the PM tests and the FM fabrication starts from next year, 1999. The paper presents the latest mission description around the asteroid and shows the current status of the spacecraft as well as the instruments and so on. The mission will be the good example of an international collaboration in the small interplanetary exploration.