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The electrical power system (EPS) of Korean satellites in low-earth-orbit is designed to achieve energy balance based on a one-orbit mission scenario. This means that the battery has to be fully charged at the end of a one-orbit mission. To provide the maximum solar array (SA) power generation, the peak power tracking (PPT) method has been developed for a spacecraft power system. The PPT is operated by a software algorithm, which tracks the peak power of the SA and ensures the battery is fully charged in one orbit. The EPS should be designed to avoid the stress of electronics in order to handle the main bus power from the SA power. This paper summarizes the results of energy balance to achieve optimal power sizing and the actual trend analysis of EPS performance in orbit. It describes the results of required power for the satellite operation in the worst power conditions at the end-of-life, the methods and input data used in the energy balance, and the case study of energy balance analyses for the normal operation in orbit. Both 10:35 AM and 10:50 AM crossing times are considered, so the power performance in each case is analyzed with the satellite roll maneuver according to the payload operation concept. In addition, the data transmission to the Korea Ground Station during eclipse is investigated at the local-time-ascending-node of 11:00 AM to assess the greatest battery depth-of-discharge in normal operation.

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An AFM tip silicon nitride cantilever was fabricated to observe thermal characteristics in order to increase data writing speed and lower power consumption. By using time dependent resistance and temperature dependent resistance curves of heating tip in experimental results, the changes of temperature on the tip were compared with simulated data. It was found that the thermal time constant of silicon nitride cantilever was 48 μs at 4 V input for 20 μs and 37 μs at 5 V input for 25 μs. Throughout the design modification, the model which has 0.5 μm, 2:1, 1000 Ω/□ shows the lowest power consumption. By changing the heating time, the power consumption of 0.158 mW and thermal time constant of 75 ns were finally observed.