Exobiology missions proposed in Japan to utilize International Space Station

The Japanese portion of International Space Station offers opportunities to conduct exobiology experiments and observations at its exposed facility. Preparatory studies have been conducted to define proposals for its possible utilization. Research subjects have been proposed from quite diverse fields of exobiology. It ranges from a basic scientific mission, such as a survey on formation and fate of organic materials under space environment, to a part of an engineering project related to quarantine technology for planetary probes dedicated to exobiology exploration. Besides technical feasibility of implementation of those payloads on the space system, scientific assessment is strongly required to elucidate key issues of exobiology conducted in near Earth orbit. Even research facilities in low Earth orbit, although literally in space, give quite a different environment from that of interstellar space in many aspects. Scientific significance of conducting exobiology there should be based on uniqueness of employing microgravity and its synergetic effects with other factors for exobiology. Because of the quite limited chance of executing space experiments, as well as high cost of its execution, proposed subjects should be proved to possess great competitiveness against studies on the ground where space environment could also be well simulated with less cost. An international forum for exobiology might play an important role to formulate prioritized plan and strategy of the discipline. Such a body could orchestrate exobiology in Earth orbit under complementary relationships among scientific endeavors carried on by scientists who participate in collaborative efforts. (C) 1999 COSPAR. Published by Elsevier Science Ltd.