We don't need to cool it down. We could float a platform about 49.5 km above the surface of Venus, where the temperature and pressure nearly match the earth at sea level. To launch a probe, we could simply drop it from the platform.
my comment was in response to parent saying venus was a better candidate for colonization than mars.
but i am totally on board with exploring venus, although im not convinced the atmospheric issues are significantly lesser than the surface, just different (hurricane winds, sulfuric acid, etc)
CO2 has carbon in it. Strip off the oxygen to breathe, the rest makes very strong building material.
Attach hydrogen, you get rocket fuel. Or plastic. Bind in some nitrogen, you can have proteins. There is probably silane lower down; send down a balloon to collect it, for silicon. Or all the way to the surface, to collect rocks.
Nuke power is totally practical there; no shielding needed, or worry about leaks; you just hang it a mile below your living-space balloons.
Is Mars' gravity too low for long-term habitation?
I know that we know that zero-G is a negative, but do we have any idea if it's a threshold that needs to be reached, a linear response to G-force that scales from untenable to fine, etc?
I would imagine that it's going to be a gradient. Just like any other form of exercise, the more effort you put in, the more positive effect. Humans would need to put in much less effort on Mars. Once we are spread across the solar system there will probably new exercise systems for 0 and .3 G environments.
We can float things in the earth atmosphere at sea level. My completely ignorant prior is that we should be able to do it there too, if the temp and pressure are the same.
Most methods of flying things through Earth's lower atmosphere should apply well to Venus at 50 km: balloons, planes, helicopters, etc. To gather energy for rotors, maybe we could siphon heat from below to power a generator or other type of converter.
Send your mining robot below. It cools itself with phase change liquids, but also opens high pressure tanks to the 90 bar atmosphere. When you hoist it back, just plug those pressure tanks in to turbines connected to generators. That wouldn't be a huge amount of power, but maybe wildcat prospectors could operate like that in the early days.
Would it be enough energy to compensate for the work you'd need to do to lift the robot back up? Presumably there's some energy gained from sending it down but not enough to bring it back, especially since it is coming back heavier. I just don't know how to work the math on that.
Why not use liquid oxygen as the phase change liquid? Then the gas could be caught in a bladder tethered to the ground. When it comes time to ascend, use it as a balloon?
There must be some way to exploit the temperature difference between the surface and 50km up, without mega-engineering.
OK that's just opened my eyes a little. It sounds so obvious - if the atmospheric pressure is the same then yes we should be able to fly aircraft. Maybe not with the engines used on Earth but in principle at least. Slightly terrifying that a loss of power should result in a 50km drop to a crushing hot acid death, but probably not much worse in reality to smashing into rock like you would on earth. Very interesting comment - thanks!
> "Most methods of flying things through Earth's lower atmosphere should apply well to Venus at 50 km: balloons, planes, helicopters, etc."
The kind of flying logistics needed to operate a station like the one proposed is something that hasn't been demonstrated on Earth, so doing it on Venus seems like one hell of a stretch. The closest match is the airship aircraft carrier experiments, which did not go well. If it can't work reliably on earth, how can it work reliably above Venus?
I think it's one of those things that looks great on paper but in reality has a ton of trouble. I think airships are like that on Earth and on Venus.
We don't need to cool Venus down, but in a few hundred years we might need to cool the earth, so learning how to do that on Venus might be a good idea.
Just because you are at sea level, you can't suddenly float stuff in the air. I like your optimism though. :) I was imaging a floating city like cloud city in star wars [0].
This is a bit more thought out than perhaps OP applied, several theretical investigations have been done into floating cities on venus and it more or less comes down to building blimps out of gasses like nitrogen and oxygen. Because the venus atmosphere is so dense, this would actually work.
Mars' atmosphere is 95.3% carbon dioxide, which means that the problem we have to solve is not "how do we inject craptons of greenhouse gas into the atmosphere" but "how do we stop the solar wind from stripping away the atmosphere," which is not a problem we have a clear idea as to how to solve.
Contrary to popular belief, the rate that solar wind strips Mars atmosphere is so ridiculously low that we can comfortably kick the problem of stopping it down the road a few hundred thousand years. If we manage to generate a habitable climate by terraforming with additional heat and atmosphere, adding a magnetic field becomes a very low priority.
Carl Sagan once proposed an interesting concept of terraforming Venus by floating some kind of bacteria in its atmosphere. The bacteria would be constantly drifting down to the surface and dying, but with no predators and ample resources, multiplying quickly enough to replace the losses, and small enough to be kept aloft by air currents. Gradually they would transform the carbon back into solid mass, and bring the atmospheric pressures and temperatures down to earth levels.
Later on in his career he decided against that scheme, but with our progress in biotechnology, it might be the only feasible approach.
I wouldn't say we know exactly how to heat up Mars. Without a magnetic field, any atmosphere we conjure out of the polar regions would escape into space. We are far, far closer to completely reversing the effects of climate change on Earth than we are to teraforming Mars.
Convert that into tonnes, and then calculate how much biosphere could be supported with that volatile weight. And once it is gone, it is gone. It’s not a renewable resource. You’d be trading away billions of years of future Martian biosphere.
We do know how to cool Venus. Build a sun shade. It’s an old idea, and a simple idea, and there’s lots of engineering literature on how it can be reasonably accomplished.
