Research for the target asteroids of next asteroid sample-return mission

目前，继“隼鸟”号任务之后，对太阳系小天体的探测工作取得了进展。在接下来的小天体探索中，我们计划探索比“隼鸟”号探测的s型小行星更原始的天体。特别是以c型小行星为目标，在航天器容易到达的近地小行星中，有必要探测到许多原始型小行星。在这项研究中，首先，我们创建了宇宙飞船容易到达的近地小行星列表。对于每一颗列出的小行星，我们都调查了它的观测机会。然后，对小行星进行比色观测，有机会估计这些小行星的分类类型。观测使用东京大学木户天文台的1.05米施密特望远镜和台湾鹿林天文台的1米望远镜。到目前为止，在30多年的时间里观测到了30颗小行星，并成功地估计了20颗小行星的分类类型。其中5颗是c型小行星。虽然在我们研究之前，航天器容易到达的c型小行星只有7颗，但加上我们的研究结果和目前其他研究者的观测结果，c型小行星的总数已经达到了15颗。这个数字基本上与。开始这项研究之前的预测。由于易于航天器探测的c型小行星数量的增加，探测计划的设计灵活性提高，任务的可行性也在提高。基于这些结果，1999JU3是一颗c型小行星，被选为2010年代初发射的“隼鸟2号”任务的主要候选者。本研究考虑了探测器1999JU3的具体轨道规划。根据这项调查，它清楚地表明，我们可以使用类似于“隼鸟”飞船的航天器来探索这颗小行星。少

At present, examinations of the explorations for small solar system bodies, which are following the "Hayabusa" mission, are advanced.In the next small bodies exploration, we are planning to explore more primitive bodies than S-type asteroids which were investigated by "Hayabusa" mission.In specially, C-type asteroids are considered as the targets and it is necessary to detect many primitive type asteroids in the near-Earth-asteroids with which a spacecraft reaches easily.In this research, at first, we created the list of near-Erath-asteroid with which a spacecraft reaches easily.As for each listed asteroid, we investigated its observing opportunity. And then, colorimetric observations were conducted for the asteroid which have observing opportunity to estimate the taxonomic type of these asteroids.Observation uses the 1.05-m Schmidt telescope of the University of Tokyo Kiso observatory, and the 1-m telescope of the Taiwan Lulin astronomical observatory.30 asteroids were observed in thr … More ee years until now, and it has succeeded in estimating the taxonomic type for 20 asteroids. Five were C-type asteroids among these.Although the number of the C-type asteroids which a spacecraft reach easily was only seven before our research, total number of the C-type asteroids becomes 15 including the result of our research and the observation result of other researcher at present.This number is mostly in agreement with. the prediction before starting this research.As the result of increasing the number of C-type asteroids which are easy to investigate by spacecrafts, the design flexibility of an exploration plan goes up and the feasibility of the mission is improving.Based on these results, 1999JU3 which is C-type asteroid is chosen as a leading candidate for the "Hayabusa 2" missions in which the spacecraft will be launched in early 2010s.In this research, the concrete orbital plan of the spacecraft in the case of exploring 1999JU3 was considered. According to this investigation, it was shown clearly that we can explore this asteroid using the spacecraft designed comparable as the "Hayabusa" spacecraft. Less