3 ms·

Mercury won't be under any serious consideration for habitation for a long time. It is down at the bottom of the biggest gravity well within a few light years.

Mercury won't be under any serious consideration for habitation for a long time. It is down at the bottom of the biggest gravity well within a few light years. Too much delta-V to come or go. It is the least explored inner planet for a reason. I think you are drastically overstating the difficulty of heating a lunar polar base. You are surrounded by vacuum, one of the best insulators around. It can be used. Of course a lunar base would probably be underground (for more radiation protection) and the lunar soil would quickly wick heat away. Simple to deal with. Excavate a small cavern and suspend the base inside the cavern. Aluminize the cavern walls if possible. Now the colony has its own thermos bottle and staying warm is easy. Sunlight is just as intense at the lunar poles as the equator. The ground receives less solar energy, but that doesn't mean that less energy is present. In fact there is more solar energy available at some sites since the panels could receive light continuously instead of in 28 day cycles. (Might require putting the panels up on a tower to help reduce libration shadows?)

drostie 9y ago
A solar panel tower at the North Pole of the Moon might be a really good idea for solving these problems, yes. Vacuum is only one of the best insulators around if you're near other warm things, I'm afraid. Out in space the dominant form of heat exchange is the Stefan-Boltzmann law, which says that if you have a half-acre of total surface area on your moon-base, and it's at 300 kelvin, then you need to supply about a megawatt to keep it warm. It's not an insurmountable problem, of course -- Tesla just announced a battery for Australia at 129 MW-hrs, which would sustain the thing for 5 days, which is not enough but it's only a half-order of magnitude off. (I'm also not considering something like nuclear heating; it's not uncommon to have a 1000-megawatt nuclear reactor in the US and that's just the power output, not the heat -- so it's not a terribly bad way to go if you can shield the rest of the base from it. The only hazard with that is one recently discussed by John Oliver on his show, firing nuclear things into space is heavily, heavily complicated by the nowhere-near-close-enough-to-zero failure rate of launch rockets and the insanely-scary-cost of distributing a bunch of reactor-grade nuclear fuel into the atmosphere.)
- keenerd 9y ago
  I still think you are overstating things. Stefan-Boltzmann is just a fancy way to say radiation. That is more or less a solved problem with nested shells. Each layer of shell cuts the losses in half. But let's ignore that for now, since more than one layer of shell complicates construction. Historical aside: before we had good solar panels, people tried crazy stuff like the Phaeton satellite that used a generator spun by a heat engine powered by liquid mercury heated by parabolic reflectors. Let's bring that idea back. 1MW only requires a 30 meter by 30 meter thermal solar collector. Pump that 1MW of heat into the hab and run a heat engine, using the shell of the hab as the thermal sink. Now that constant 1MW drain is a required feature.

drostie 9y ago

A solar panel tower at the North Pole of the Moon might be a really good idea for solving these problems, yes. Vacuum is only one of the best insulators around if you're near other warm things, I'm afraid. Out in space the dominant form of heat exchange is the Stefan-Boltzmann law, which says that if you have a half-acre of total surface area on your moon-base, and it's at 300 kelvin, then you need to supply about a megawatt to keep it warm. It's not an insurmountable problem, of course -- Tesla just announced a battery for Australia at 129 MW-hrs, which would sustain the thing for 5 days, which is not enough but it's only a half-order of magnitude off. (I'm also not considering something like nuclear heating; it's not uncommon to have a 1000-megawatt nuclear reactor in the US and that's just the power output, not the heat -- so it's not a terribly bad way to go if you can shield the rest of the base from it. The only hazard with that is one recently discussed by John Oliver on his show, firing nuclear things into space is heavily, heavily complicated by the nowhere-near-close-enough-to-zero failure rate of launch rockets and the insanely-scary-cost of distributing a bunch of reactor-grade nuclear fuel into the atmosphere.)

keenerd 9y ago
I still think you are overstating things. Stefan-Boltzmann is just a fancy way to say radiation. That is more or less a solved problem with nested shells. Each layer of shell cuts the losses in half. But let's ignore that for now, since more than one layer of shell complicates construction. Historical aside: before we had good solar panels, people tried crazy stuff like the Phaeton satellite that used a generator spun by a heat engine powered by liquid mercury heated by parabolic reflectors. Let's bring that idea back. 1MW only requires a 30 meter by 30 meter thermal solar collector. Pump that 1MW of heat into the hab and run a heat engine, using the shell of the hab as the thermal sink. Now that constant 1MW drain is a required feature.