Technical Paper
Recovery From One Failure During Early Assembly Stages of the International Space Station
2001-07-09
2001-01-2400
Primary source of electric power for the International Space Station (ISS) is the photovoltaic module (PVM). At assembly complete stage, the ISS is served by four PVMs. Each PVM contains two independent power channels such that one failure will result in loss of one power channel. During early stages of assembly, the ISS is served by only one PVM and one power channel failure has a more significant impact on the ISS electric power capability. In the limited context of this study, the early stages are limited to stages 4A and 5A. Power channel components are arranged in orbital replaceable units (ORU) and repairs are accomplished by replacing these ORUs. While a power channel is operating, all of its ORUs are maintained within their allowable temperature ranges by a balance between the heat generated and heat removed. Heat removal is accomplished either passively or by an active thermal control system, called photovoltaic thermal control system (PV TCS).