ENAE 483/788D
Principles of Space Systems Design
Fall, 2002

Question 11:

For both ENAE 483 and ENAE 788D:

You have to choose the configuration of the power system for a small manned spacecraft which will operate in low earth orbit. Assume that the orbital period is 93 minutes, with 44 minutes of darkness each orbit. The spacecraft needs a steady 5 kW power supply at all times. The problem is that you don't know the mission duration - it could be as little as one orbit, or as much as a month. Plot the power system mass versus mission duration for each of the following candidate systems:

a) NiMH primary battery, 160 Whr/kg

b) Shuttle fuel cells and tanks, as per Lecture 14, page 19

c) AEC-Able Ultraflex-style silicon arrays, with parameters given in Lecture 14, page 5
Battery energy storage for night passes using NiMH secondary (rechargeable) batteries at 80 Whr/kg

d) Galileo RTGs, with specs as per Lecture 14, page 12 (use EOL power numbers)

Submit the results in the form of a concise (no more than two pages) Powerpoint presentation which will make clear to the program managers what the optimum decisions are as a function of mission duration, and documenting clearly and concisely (high information density!) your assumptions, analytical results, and conclusions.