• Turuo Torikai
• Koichi Yonemoto
• Osamu Kitayama
• Akira Miyahara
• Kazutaka Iwama
• Shunichi Okaya
• Sadao Kondo

Due to the growing international recognition of the academic activities on space tourism by the Japanese Rocket Society (JRS) with the vehicle's name of Kankoh-maru, the Transportation Research Committee has decided to study safety standard for designing space tour vehicles as a third phase research program. The reason is clear why the establishment of the safety standard is necessary. There must be clear promises to space line companies that this kind of commercial transportation system is fundamentally safe in design for passengers. Thus the "spaceworthiness" is to be provided now.

The Japanese aviation regulations have been established by the Civil Aircraft Bureau of the Ministry of Transportation in 1952. The third phase study has begun to review the airworthiness that are specified for the airplane category type T and the rotorcraft category type TA/TB. Then the applicability to space tour vehicles has been assessed. Since the space tour vehicles are operated beyond the regimes in speed and altitudes of subsonic and supersonic aircraft, the certification regulations are to be tailored, modified and added with new issues of environmental conditions during exo-atmospheric and reentry flight.

Concerning safety, there is a fundamental difference in design between conventional rockets and space tour vehicles. Since the expendable rockets are designed based on the piling of the reliability of onboard components, the launch success is expected by the figure of probability. If an accident occurred, the rocket will be destroyed by the command from ground for the safety of residents. On the other hand, deterministic safety is required for the space tour vehicles not only by the reliability approach of redundant system but also by the abort operation for the unexpected subsystem failure. The space tour vehicles primary consider the safety of passengers and will never be destroyed.

The Transportation Research Committee has employed an idea of "integrated certification process" that the space tour vehicles are to be designed with "built-in" safety margins based on the existing commercial aircraft's fail-safe design rule. It must be the shortest way of realizing commercial space tour to inherit the property of the aircraft's safety philosophy.