I would like help in designing a manned craft for exploration and mining activities on Ceres.

The sunlight reaching Ceres is approx 10% of that in LEO. Does this mean the spacecraft would have trouble keeping warm, or cool? Would spacecraft around Ceres need to use reflective foil covers, thermal blankets, white paint etc? Or will they be black, to absorb and heat up as much as they can?

Would they also require radiators to give off excess heat? Assume a present-day level of technology.

  • 1
    $\begingroup$ Almost certainly will need some kind of radiator system. Think details are needed though. Power budget, volume of spacecraft, crew #, etc. $\endgroup$ Commented May 24, 2020 at 20:04
  • $\begingroup$ The problem is almost always being too hot, not too cold, if you have humans and their life support aboard. $\endgroup$
    – ikrase
    Commented May 25, 2020 at 0:06

1 Answer 1


In short: the answer is yes to all of the above and the amount of each depends on details.

Thermal design of spacecraft usually starts out with assumptions regarding the size, total heat loads, and temperature limits of components. Manned spacecraft have an additional level of complexity due to the requirements needed for comfortable living in cramped quarters. Adding even more complexity comes from the reduced insolation leading to a design trade between large solar panels or an RTG that typical deep space craft use for electricity.

No matter which approach is used, avionics, humans, and a possible RTG will produce waste heat which will have to be radiated out to space meaning that, yes radiators will be needed. This is true for all spacecraft; heat can only be removed by radiation. The specific coating of the radiator is always up for trade (white paint, silver-coated Teflon, optical solar reflectors are a few examples). A black radiator emits heat roughly as well as it absorbs sunlight, so as the spacecraft travels further away from the sun, it'll absorb less solar heat.

As far as reflective foil and thermal blankets, these are typically made from multi-layered insulation (MLI) which are generally used for a two-fold purpose: to reflect incoming solar radiation and to keep heat inside. For such a cold target environment as Ceres, a significant portion of the spacecraft will likely need to be covered in blankets to keep the heat in while a few target areas will act as radiators. Heat from the air conditioning and system avionics systems would likely be routed to those radiators conductively or through heat pipes.

  • $\begingroup$ If keeping warm is the challenge, why would you route heat to the radiators when you could route it into the cabin? $\endgroup$
    – Innovine
    Commented May 25, 2020 at 15:18
  • $\begingroup$ If you don't let any heat escape, temperatures will rise until something breaks. So the combination of blankets and radiators lets you tune the temperatures to exactly what you need. Also, it's impossible to prevent any heat from ever escaping, everything radiates heat. Consider drawing a control volume while thinking about the First Law of Thermodynamics, heat out must equal heat in plus any heat generated. $\endgroup$
    – aranedain
    Commented May 26, 2020 at 17:59

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