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A point in favor is that normal earth-like atmosphere is a lifting gas on Venus, so just large, lightly built structures would float naturally. The main point

A point in favor is that normal earth-like atmosphere is a lifting gas on Venus, so just large, lightly built structures would float naturally. The main point against is that there is no reason for anyone to go there. Cloudtops on Venus are immensely resource-poor, most importantly in hydrogen. I agree with you that there is no advantage to a floating colony over a spinning one. The one place on the solar system whose colonization is often ignored is Mercury. It has an extremely low axial tilt, meaning that all the craters on it's poles are permanently shadowed. It is also constantly bombarded by solar wind, which produces water (ionized hydrogen impacts oxide rocks, and binds to the oxygen). Then the water is a gas that bounces around until it impacts the bottom of a shadowed crater, which is cold enough to freeze it. Based on data from the MESSENGER mission, the south pole of Mercury alone has more water than all of Mars.

_dain_ 4y ago
>A point in favor is that normal earth-like atmosphere is a lifting gas on Venus, so just large, lightly built structures would float naturally. That's not really a point in favour compared to an orbiting spinhab. You only need it to float so that it doesn't fall to the ground. And you can achieve that by not leaving orbit in the first place.
- shkkmo 4y ago
  A orbital habitat struggles with higher pressure differentials, no gravity and more challenging thermal management. A floating habitat would have less access to orbit, would have density / weight contraints and would have to deal with the corrosivity of the venusian clouds.
  - _dain_ 4y ago
    Gravity I'll grant you, but heatsinks are not difficult technology, and Venus has its own problems with pressure. It's not the overall pressure you worry about; each component of the gas has its own partial pressure. The outside is poison and it's trying to get into the livable parts, and that partial pressure against the breathable air is of the same order of magnitude as breathable air against a vacuum. The engineering challenges are similar.
    - shkkmo 4y ago
      > that partial pressure against the breathable air is of the same order of magnitude as breathable air against a vacuum. The engineering challenges are similar. Those are very different engineering challenges. Separating similar pressure gas mixtures is question of porosity, but not force. Separating different pressures of the same gas mixture is not just a question of porosity, but you also need manage the forces created by the overall pressure differential. Edit: If you take a helium balloon into space (or high enough in our atmosphere) it explodes rather than just slowly leaking and equalizing it's gas mixture with the atmosphere.
      - _dain_ 4y ago
        Yes you're right, I didn't think it through properly
adwn 4y ago
> Based on data from the MESSENGER mission, the south pole of Mercury alone has more water than all of Mars. That will come in handy when we deconstruct Mercury to provide the raw materials for a Dyson swarm.
dotnet00 4y ago
On the other hand Mercury is pretty hard to get to.
- chucksmash 4y ago
  (Because Earth isn't at rest, it's travelling at 30km/s around the sun, and that's a free boost in terms of getting out of the solar system but velocity you need shed to lower your orbit sunward.) So, AIUI, it's easier to get to Alpha Centauri than to "fall into" the star we orbit.

_dain_ 4y ago

>A point in favor is that normal earth-like atmosphere is a lifting gas on Venus, so just large, lightly built structures would float naturally. That's not really a point in favour compared to an orbiting spinhab. You only need it to float so that it doesn't fall to the ground. And you can achieve that by not leaving orbit in the first place.

shkkmo 4y ago
A orbital habitat struggles with higher pressure differentials, no gravity and more challenging thermal management. A floating habitat would have less access to orbit, would have density / weight contraints and would have to deal with the corrosivity of the venusian clouds.
- _dain_ 4y ago
  Gravity I'll grant you, but heatsinks are not difficult technology, and Venus has its own problems with pressure. It's not the overall pressure you worry about; each component of the gas has its own partial pressure. The outside is poison and it's trying to get into the livable parts, and that partial pressure against the breathable air is of the same order of magnitude as breathable air against a vacuum. The engineering challenges are similar.
  - shkkmo 4y ago
    > that partial pressure against the breathable air is of the same order of magnitude as breathable air against a vacuum. The engineering challenges are similar. Those are very different engineering challenges. Separating similar pressure gas mixtures is question of porosity, but not force. Separating different pressures of the same gas mixture is not just a question of porosity, but you also need manage the forces created by the overall pressure differential. Edit: If you take a helium balloon into space (or high enough in our atmosphere) it explodes rather than just slowly leaking and equalizing it's gas mixture with the atmosphere.
    - _dain_ 4y ago
      Yes you're right, I didn't think it through properly

adwn 4y ago

> Based on data from the MESSENGER mission, the south pole of Mercury alone has more water than all of Mars. That will come in handy when we deconstruct Mercury to provide the raw materials for a Dyson swarm.

dotnet00 4y ago

On the other hand Mercury is pretty hard to get to.

chucksmash 4y ago
(Because Earth isn't at rest, it's travelling at 30km/s around the sun, and that's a free boost in terms of getting out of the solar system but velocity you need shed to lower your orbit sunward.) So, AIUI, it's easier to get to Alpha Centauri than to "fall into" the star we orbit.