QSAT mission analysis and operation plan design

This paper deals with the operations concept for the small satellite QSAT. It aims to guarantee the survivol of the satellite ond to accomplish the scientific observations during the planned lifetime of one year. QSAT is developed at the Space Systems Dynamics Laboratory of Kyushu University in Fukuoka, Japan. Its main objectives are the porallel measurements of the geomagnetic field and the electric potential of the satellite, which may lead to new insights on the mechanisms of spacecraft charging. The uniqueness of this mission is the regard of Field-Aligned-Currents as the reason for spacecraft charging. Simulation results are presented, which are the basis for the operations plan along with common-sense considerations. Specific strategies are presented which allow to accomplish the mission requirements within the given constraints. The paper gives the break-down of QSAT lifetime into specific phases and cycles, and the allocation of the defined modes. Only about 32 minutes of ground-station visibility are available per day, thus only about 2 Mbytes of data can be downlinked at the transmission rate of 9.6 kbits per second. As part of mission operations, "predict-prevent" style considerations of contingency procedures are discussed. This facilitates o rapid answer to occurring anomalies.