Launch window design for the Magnetospheric Multiscale (MMS) mission ensured that no excessive eclipses would be encountered during the prime mission. However, no orbit solutions exist that satisfy the eclipse constraints indefinitely: most extended mission years contain 1–3 eclipses long enough to potentially damage either the spacecraft or its scientific instruments. Two steps were taken to improve the situation. Firstly, raising apogee radius from 25 to 29.34 Earth radii altered the Sun-Earth-MMS phasing, so efficiently achieving reductions in the long eclipse durations. These maneuvers were performed in February 2019, in preparation for the first pair of long eclipses during the subsequent August. Secondly, a set of operational steps were taken around the time of the eclipses to help maintain spacecraft and instrument temperatures while preventing power load shedding. These steps included raising key onboard temperatures through adjusting the spacecraft attitude to tilt the instrument deck towards the Sun, and engaging select heaters prior to going into eclipses. In addition, all scientific instruments were turned off, as well as high-power, non-critical spacecraft systems, to conserve energy. These steps each came with trade-offs which will be discussed in the paper. Finally, the results that were obtained when the spacecraft experienced the first set of extremely long eclipses will be discussed, as will lessons learned for future long eclipses.
Operational Techniques for Dealing with Long Eclipses during the MMS Extended Mission
2020-03-01
6454381 byte
Aufsatz (Konferenz)
Elektronische Ressource
Englisch
Operational Availability - Extended Mission Operations
NTRS | 2019
|Operational Availability - Extended Mission Operations
NTIS | 2019
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