[rocmcd]

How is living in space meaningfully different from living in a submersible in the ocean (apart from the view)?

You would think we would get really good at the latter before going after the former, and yet I see no interest from people wanting to live in a (shallowly submersed) submarine. It would also be an order of magnitude less expensive and dangerous.

[ryandrake]

Heck, we can barely build permanent settlements in many places on Earth like Antarctica and deep inside many deserts. And, here we have 1G gravity, 1bar breathable air pressure, a magnetic field and shielding from radiation. We don't have any of that outside of Earth.

If we can't build, say, a 10K-person inhabited city on the south pole, how can we even imagine we can build it on the moon or Mars?

[numpad0]

Can't agree more. There needs to be something like, a Manhattan sized building in the middle of Africa, with an air-cooled nuke in the center, and a fully self contained modern city, complete with suburban forests, inside. If that isn't going to work for any reasons other than for environmental protection, so wouldn't a Mars settlement.

[inetknght]

> How is living in space meaningfully different from living in a submersible in the ocean (apart from the view)?

Just off the top of my head:

- different ability to re-stock

You could re-stock your submersible just about anywhere. You're going to have to do a lot more planning for your groceries when you go in space though.

- access to microgravity

This simply isn't available in a submersible. Microgravity provides some interesting manufacturing and biological capabilities.

- completely different pressure profiles

Combining different pressure environments in microgravity is particularly interesting to me.

- different instrumentation capabilities

It's not just the view -- the atmosphere plays merry hell with instruments when measuring the cosmos. And it does so in ways that just aren't relevant to underwater environments.

[margalabargala]

Gravity or lack thereof is a big one.

[rocmcd]

Have you seen what happens to people who live in zero gravity for long periods of time? It doesn't sound fun. I do get the appeal of wanting to experience it for a short period of time, though.

I would also say that scuba diving is probably the closest you can get to experiencing anything close to zero gravity on Earth.

[margalabargala]

Sure, living in zero G for a long period of time is not good for you.

You asked how space was different from a submersible. I gave you one difference, you expanded on that to a second.

[philwelch]

Any space colony intended for long term habitation would create artificial gravity through centrifugal force. It's completely doable using materials sourced from the Moon and near-Earth asteroids; there are design studies dating back over fifty years.