Assume that a satellite can be modeled as a thermally leading sphere with radius 0.5m and its energy consumption is 200W, and its surface can be described with α=0.3 and ε=0.9.
Determine the equilibrium temperature of satellite in these cases:
a) Satellite is between earth and sun;
b) Earth is between satellite and sun;
c) Satellite is far away from stars or planets.
Assume that Suns radiation is 1367 Watt/m^2, from earth reflected 410 Watt/m^2 and that earths thermal radiation can be modeled as black body radiation with temperature T=255 K.

Question

Assume that a satellite can be modeled as a thermally leading sphere with radius 0.5m and its energy consumption is 200W, and its surface can be described with α=0.3 and ε=0.9.
Determine the equilibrium temperature of satellite in these cases:
a) Satellite is between earth and sun;
b) Earth is between satellite and sun;
c) Satellite is far away from stars or planets.
Assume that Suns radiation is 1367 Watt/m^2, from earth reflected 410 Watt/m^2 and that earths thermal radiation can be modeled as black body radiation with temperature T=255 K.

anonymous · Answer

Teacher gave us answers so we could compare them to ours, but I can't think of the solution.

Answers are : a) 281 K     b) 245 K         c) 188 K

anonymous · Answer

what is alpha?

anonymous · Answer

@prehisto ?

anonymous · Answer

In solar thermal collectors, a selective surface or selective absorber is a means of increasing its operation temperature and/or efficiency. The selectivity is defined as the ratio of solar radiation-absorption (alpha) - to thermal infrared radiation-emission (epsilon).

anonymous · Answer

sigma is 5.67*1-^-8 (boltzmann constant)

anonymous · Answer

@prehisto get it?

anonymous · Answer

yet the answer does not match, i think.

anonymous · Answer

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