2016 年 31 巻 3 号 p. 161-168
Primitive chondrites and cosmic dust derived from asteroids and comets represent the oldest solid material in the Solar System. Although they are precious sources of information about the processes in the Protoplanetary Disk and on planetesimals, they lack “geological” information, i.e., from what parts of what bodies they originate, which have been an obstacle for scientists to deduce persuasive interpretations. Sample return missions including the Stardust and Hayabusa explorers are intended to solve this problem. This article presents the results of detailed analyses of the samples obtained by the Stardust and Hayabusa Missions. Both missions have yielded many revolutionary findings on the early and present Solar System despite the small amounts of recovered samples. Greater successes are expected from the next sample return missions currently performed and planned.