The astronaut candidate is certified as an “astronaut,” after completing basic training. The selection was carried out by few committees set up under the Japan Aerospace Exploration Agency (JAXA) Astronaut Review Board, which makes a comprehensive judgement on the suitability of applicants. JAXA determined that the examination of staying at the isolation and confinement facility was the most suitable means for experts to judge examinees with “leadership, followership, and team building skills,” which JAXA considers essential for future International Space Station (ISS) crew members. Essentially, the appropriateness of the astronaut selection result can be assessed only in a retrospective way based on the result achieved by the selected astronauts in their ISS missions. Dramatic technological sophistication in recent years has brought about various wearable sensors capable of monitoring human-to-human distances and stress reactions.