Achieving high reliability and survivability on Greenhouse Gases Observing Satellite (GOSAT)
Kaneko, Yutaka; Hamazaki, Takashi; Nakajima, Masakatsu; Kasuya, Masahiro
Japan Aerospace Exploration Agency

Greenhouse gases Observing Satellite (GOSAT) is a satellite to globally monitor the carbon dioxide (CO2) and the methane (CH4) distribution from space, and it aims to contribute to the international efforts to prevent global warming, such as the Kyoto Protocol. The GOSAT is a joint project of Japan Aerospace Exploration Agency (JAXA), Ministry of the Environment (MOE) and National Institute for Environmental Studies (NIES). JAXA is responsible for satellite development, launch, and satellite operation, and JAXA and MOE are in charge of the sensor development. While, MOE and NIES are responsible for satellite data utilization. The GOSAT is scheduled to be launched in 2008. Learning from the past experiences of unfortunate failures of the solar array paddle and power system on the Earth observing satellites ADEOS and ADEOS-II in 1997 and 2003, various techniques and countermeasures are applied to GOSAT to improve reliability and survivability of the satellite. Fundamental concept is to utilize flight proven components as much as possible. In addition to every satellite bus component, all major sensor components are equipped with a redundant system so that the satellite mission would not be interrupted during single failure. GOSAT@also has dual power bus systems. If power is reduced by half due to any failure on the single power bus line, GOSAT is designed to switch to power-saving mode and it will be able to continue minimum mission operation. Furthermore, the critical mechanical components, were subjected to mission duty cycle tests for two times the mission duration to ensure the margin of lifetime. This paper presents the system design aspects of the GOSAT with regards to improving reliability and survivability which are to guarantee five-year operation lifetime.