7.6.1 Power Budget

  

Table 11: Power Budget for Asterius

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To begin the power subsystem development, a compilation of the spacecraft components and their power requirements was developed. Each subsystem, including ACS, Communications, CD&H, Propulsion, Scientific Instruments, and Thermal, contributed to the budget, and their individual needs were tallied. The power budget is listed in Table 11. The power requirement for the overall spacecraft, with a thirty percent margin added in for error and correction factors, totaled at 1400 W. In addition to the development of the power budget, several system parameters were considered: mission life, average electrical power requirement, and peak electrical power required. Therefore, to calculate such required power values, the mission scenario was broken down into different stages per subsystem, as seen in Table 12.

  

Table 12: Power Usage by Subsystem at Each Stage of the Mission, All in Watts

Stage of Mission	ACS	Comm.	C&DH	Thermal	Sci. Inst.	Prop.	Total
Earth Parking Orbit	90	60	30	20	45	7.5	258.5
Engine Burns	96	60	30	20	45	200	451
Cruising	96	100	30	20	45	7.5	298.5
Orbiting Europa	96	100	30	20	120	7.5	373.5
Lander Scenario	96	150	30	20	120	26.36	442.36
Probe Deployed	0	180	0	0	150	7.5	337.5

The above mission scenario gave an average power requirement of 360.23 W and a peak power requirement of 451 W.