Abstract
Recent years, there are problems of design of Electricity Power Subsystem (EPS) in university satellites. For example, it becomes impossible to operate satellites because battery charging or power supplying is stopped. Therefore, it is necessary to consider power balance, charge control, sizing of solar cells, inhibit function, and others, and evaluate the system from environmental test such as thermostatic bath, vacuum, vibration, shock and so on of the EPS for the satellite beforehand. In this research, for the purpose of sharing knowledge of development of satellite, we show the case and improvement measures of EPS of 10cm class satellite SEEDS and 20cm class satellite SPROUT from the point of view of operation and development. In SEEDS from the point of view of operation, it was confirmed that battery voltage is high level voltage attributing to a causes of battery protection circuit. In SPROUT from the point of view of development, it was confirmed that EPS didn't operate normally because of voltage drop and was renovated by optimization of component placement and extending circuit pattern and harness and confirmed the operation of EPS by environmental test such as vacuum, thermostatic bath, vibration and others.
