Mission Design for the CubeSat OUFTI-1

CHAPTER 88.4 Battery and operating modesAs above mentioned, no detailed study has been conducted over the powerhardware. Anyway, in analogy with all the other CubeSats, launched or in anadvanced design phase, we will choose a lithium-ion battery because they providemore energy per kilogram than other battery types. Regarding the powerconditioning and distribution unit, a non-regulated bus possibly coupled withDC/DC converters seems the best option.The lack of active attitude control and of a specific payload simplified the identificationsof operating modes respect to power. We have in fact only two operatingmodes depending on the D-STAR system. We have three elements requiringpower: the D-STAR system, the on board computer and the radio beacon. Thelatter, as introduced chapter 10, is the safer communications system and needsa power much smaller than that of D-STAR.Table 8.4: Operating modesMODE 1 MODE 1D-STAR OFF ONONBOARD COMPUTER ON ONRADIO BEACON ON ONThe first mode is a kind on stand-by mode: the on board computer is on andthe radio beacon is sending the housekeeping data and receiving the commands.The second mode is the real operating mode when the D-STAR system is onand receiving and sending a amateur radio signal.Galli Stefania 84 University of Liège