ABSTRACT
Primitive small bodies are the remnants of planetesimals, which did not grow large enough to become planets. For understanding the history of the early solar system, it is therefore important to investigate these small bodies. In particular, it is very important to reveal the distributions and evolution of organic molecules and water in small bodies for understanding origins of life and planetary habitat.
To date, we have improved our understanding of chemical and physical processes in small bodies by chemical analyses of organics and minerals in meteorites, interplanetary dust particles, and Antarctic micrometeorites. However, there have remained uncertainties in source and geological information for their evolution. In order to link the chemical features of these extraterrestrial materials with their original parent bodies and geology, small bodies’ explorations that integrate the outcomes from observation and sample return and/or on-site analyses are necessary.
This chapter reviews (1) the achievements from the past explorations, (2) the scientific goals of the ongoing asteroid sample return missions, and (3) the scientific strategies of future missions. Integrated understanding of scientific results from explorations of the small bodies in different stages of evolution will enable the establishment of solar system science, covering from interstellar medium to planetesimals.
