For a university project I'm making thermal assumptions and introductionary design of a small satellite. Satellite electronics use around 30W energy in total (inc. Camera, on board computer etc.) . Some of 30W of course, will not be used as work but they go waste as heat. To make calculations about satellite, I need assumptions about how many watts will be dissipated as heat by electronics? What will be the waste heat? Any help would be great.

  • $\begingroup$ That should be "uses energy at a rate of about 30 Watts" $\endgroup$
    – DJohnM
    Apr 30, 2015 at 0:45

2 Answers 2


Almost all energy from a satellite will end up as heat. The exception is power that is transmitted away, which is primarily RF only. Sound and light are not options for transmission of power usually. So just assume that all electrical power turns in to heat, with possibly subtracting out the RF energy output from the transmitter.


As a first approach, you can assume all electric power will be turned into heat. Some of the power will be used to do something first, but electrical and mechanical resistance will eventually turn all power into heat.


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