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MatthewGrim / Lunar_SPS

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Implement thermal analysis model for solar power satellite #51

Closed MatthewGrim closed 4 years ago

MatthewGrim commented 4 years ago

This issue documents an attempt to replicate the original satellite thermal analysis that was carried out in the system design of a lunar SPS system. The motivation for doing this is to capture the analysis explicitly somewhere, as well as to further the analysis that we could apply to simpler studies that scan potential designs at some point in the future.

MatthewGrim commented 4 years ago

At this point, the basic model is working for a base test, but the parameters are not identical to the original results. This is most likely because there is some mismatch in the modelling of the radiator units in the power balance.

I have tested the loop heat pipe coupling, and shown that the steady state temperature for the two cases during beaming is approximately correct. In addition, the cold steady state case is approximately correct with the model that I am using. It's the transient analysis that is most likely wrong somehow. This could be the assumed radiator mass, or radiated power being too low during the period when the laser is firing.

This requires a better understanding of the radiation modeling to answer. I will leave this issue open for now. Hopefully, I can find the data I need in the literature on Deployable Radiator

MatthewGrim commented 4 years ago

The radiator specific heat capacity is probably the most likely cause of error. I do not have the actual specific heat capacity to use for the radiator, and have assumed aluminium as I know that the radiators are predominantly made with aluminium. This may not be the right thing to do.

MatthewGrim commented 4 years ago

Results for the satellite are still different from the original study results, but not considerable. The replication of the rover results has been much more successful with the assumptions for the heat capacity and mass being easier to define than the for the radiator.

The basic models used for the thermal analysis seem to be reasonable, and the results are very much in-line with the expectation from the original study. This issue should be closed.