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We are so driven by settling other planets, which of course I think we should do, that we forget that space habitats might be a more economical and also healthi

We are so driven by settling other planets, which of course I think we should do, that we forget that space habitats might be a more economical and also healthier first step into space. Apart from the ones depicted in these images I'm more in favour with starting with cheaper techniques where we could wire up an initial station to a wire/tether, and put a weight (or another small station) at the other end, have them spin around to reproduce gravity. Then we can move these pieces closer to asteroid belts to get resources. A planet on the other hand is a gravity-well: it will always cost us energy and money to get out of such wells. My point is that we should start in pieces, and not necessarily put all our efforts to reach a planet. There can be many other steps in between.

skriticos2 8y ago
My thoughts exactly. Especially since it's much easier to simulate 1 gravity in space with rotating space stations. (You live long enough on Mars/Moon/etc., you are not coming back without being crushed). The stations would need to be rather large, but that's just an engineering and motivation problem. But with a little extra shielding (lot's of water in the hull - could be obtained from asteroids) they'd be very useful as living space (especially after climate change ravages our home planet). They'd also be much better staging places for solar system exploration and have an advantage in trade (refueling, low energy requirement to get anywhere, excellent target for asteroid refinement without having to bring stuff into a gravity well and back up). Not having to fight the atmosphere for solar energy is also a plus. But humanity still clings to traditional gravity wells like the images in the OP show. Old Italian land-house style dwellings in an orbital ring station..
- z3phyr 8y ago
  > but that's just an engineering and motivation problem Its a feasibility problem mostly.
- kuhhk 8y ago
  > But with a little extra shielding (lot's of water in the hull What's the purpose of the water? If a micro-asteroid punctures the hull, does the water freeze to stop the leak?
  - zbentley 8y ago
    Radiation shielding: http://www.adl.gatech.edu/research/tff/radiation_shield.html http://www.adl.gatech.edu/research/tff/radiation_shield.html
taf2 8y ago
I think that is why Nasa's Havoc mission is maybe the best idea yet... https://www.youtube.com/watch?v=g-vK9pqonAE https://www.youtube.com/watch?v=g-vK9pqonAE You still have to maintain the floating city like you would an orbital one, but you get the extra added benefits... Venus makes the most sense to me... You get the benefit of gravity similar to earth, 70~ deg f temp and gases that allow you to maintain pressure and possibly harvest for fuel...
- lxmorj 8y ago
  I've been trying to figure out how effective solar power would be at the height you'd put a floating city. You're closer to the sun than Earth, much higher than Earth's surface, but in a very dense atmosphere...
  - swish_bob 8y ago
    It's Venus, you could do the equivalent of geothermal energy generation just by dangling the pipes beneath you, no drilling required ...
  - ido 8y ago
    If atmospheric pressure at that height is similar to earth's at sea-level, wouldn't we expect similar levels of light blocking by the atmosphere as well?
    - emiliobumachar 8y ago
      Possibly. But if there are permanent clouds above, the whole idea falls flat.
  - ido 8y ago
    What is the cost/difficulty difference in getting to Venus in the first place & then getting people/supplies back-and-forth compared to LEO?
kakarot 8y ago
From what I understand, a structure needs to be quite massive to get meaningful gravity from a rotating hull unless you attempt to approach ludicrously unsafe angular velocity which would make repair / docking a big challenge. In The Expanse, Ceres station was spun up over many, many years and still only achieved about 1/3G. Not to use a fictional universe as a basis for science but afaik they at least tried to do the math correctly.
- AllegedAlec 8y ago
  > From what I understand, a structure needs to be quite massive to get meaningful gravity from a rotating hull unless you attempt to approach ludicrously unsafe angular velocity which would make repair / docking a big challenge The reason it has to be so massive is that otherwise the difference in the G-forces between your head and your feet can make you sick[1]. 1: http://www.spacefuture.com/archive/inhabiting_artificial_gravity.shtml http://www.spacefuture.com/archive/inhabiting_artificial_gra...
  - alex_duf 8y ago
    They talk about it in the book, it actually makes some of the characters sick
    - AllegedAlec 8y ago
      Yeah, I know. I just wanted to elucidate for others who may not have read the book what some important reasons are for making rotating ring structures quire large.
- alex_duf 8y ago
  There's also Medina station which has the massive drum they end up spinning. They then grow crops in it. I love the expanse, such an amazing series of books
  - kakarot 8y ago
    Easily my favorite contemporary sci-fi series... but please feel free to change my mind on that.
timbit42 8y ago
A station with a counterweight can be grown into a wheel station. A wheel can be widened until it becomes a tube station.
tomp 8y ago
I agree, except for the availability of resources, a space station makes much more sense than a planetary colony. In addition, all stations depicted are highly sci-fi - a realistic station would have to be modular, to prevent catastrophic failure if anything goes wrong (i.e. at most one module is lost, all the air in the whole station). The up-front costs are way bigger, because you have to manufacture a reinforced floor (which, in case of a planetary colony, is the planet itself) and spin up the station (to provide "gravity"). But operational costs should be much lower, because there is 0 delta-v to get to and from the station (except syncing orbits, which you need to do with a planet as well). Start with two modules tethered in spin, then add additional ones gradually. If we transport the materials from Earth, the cost of initial material is similar to settling on a planet. Once we develop technology for off-world manufacturing, you can literally fly your manufacturing plant to an asteroid, build the station there (with plenty of resources available) and then reposition it however you want. The only kinds of planets that it makes sense to settle, is ones with a magnetosphere - and even that only until we develop other ways of shielding (there are companies working on that - e.g. Talos http://spacetalos.com/ http://spacetalos.com/ )
justanegg 8y ago
you could also build it in space over the course of year and land it on a place with lower gravity than earth easily.

skriticos2 8y ago

My thoughts exactly. Especially since it's much easier to simulate 1 gravity in space with rotating space stations. (You live long enough on Mars/Moon/etc., you are not coming back without being crushed). The stations would need to be rather large, but that's just an engineering and motivation problem. But with a little extra shielding (lot's of water in the hull - could be obtained from asteroids) they'd be very useful as living space (especially after climate change ravages our home planet). They'd also be much better staging places for solar system exploration and have an advantage in trade (refueling, low energy requirement to get anywhere, excellent target for asteroid refinement without having to bring stuff into a gravity well and back up). Not having to fight the atmosphere for solar energy is also a plus. But humanity still clings to traditional gravity wells like the images in the OP show. Old Italian land-house style dwellings in an orbital ring station..

z3phyr 8y ago
> but that's just an engineering and motivation problem Its a feasibility problem mostly.
kuhhk 8y ago
> But with a little extra shielding (lot's of water in the hull What's the purpose of the water? If a micro-asteroid punctures the hull, does the water freeze to stop the leak?
- zbentley 8y ago
  Radiation shielding: http://www.adl.gatech.edu/research/tff/radiation_shield.html http://www.adl.gatech.edu/research/tff/radiation_shield.html

taf2 8y ago

I think that is why Nasa's Havoc mission is maybe the best idea yet... https://www.youtube.com/watch?v=g-vK9pqonAE https://www.youtube.com/watch?v=g-vK9pqonAE You still have to maintain the floating city like you would an orbital one, but you get the extra added benefits... Venus makes the most sense to me... You get the benefit of gravity similar to earth, 70~ deg f temp and gases that allow you to maintain pressure and possibly harvest for fuel...

lxmorj 8y ago
I've been trying to figure out how effective solar power would be at the height you'd put a floating city. You're closer to the sun than Earth, much higher than Earth's surface, but in a very dense atmosphere...
- swish_bob 8y ago
  It's Venus, you could do the equivalent of geothermal energy generation just by dangling the pipes beneath you, no drilling required ...
- ido 8y ago
  If atmospheric pressure at that height is similar to earth's at sea-level, wouldn't we expect similar levels of light blocking by the atmosphere as well?
  - emiliobumachar 8y ago
    Possibly. But if there are permanent clouds above, the whole idea falls flat.
- ido 8y ago
  What is the cost/difficulty difference in getting to Venus in the first place & then getting people/supplies back-and-forth compared to LEO?

kakarot 8y ago

From what I understand, a structure needs to be quite massive to get meaningful gravity from a rotating hull unless you attempt to approach ludicrously unsafe angular velocity which would make repair / docking a big challenge. In The Expanse, Ceres station was spun up over many, many years and still only achieved about 1/3G. Not to use a fictional universe as a basis for science but afaik they at least tried to do the math correctly.

AllegedAlec 8y ago
> From what I understand, a structure needs to be quite massive to get meaningful gravity from a rotating hull unless you attempt to approach ludicrously unsafe angular velocity which would make repair / docking a big challenge The reason it has to be so massive is that otherwise the difference in the G-forces between your head and your feet can make you sick[1]. 1: http://www.spacefuture.com/archive/inhabiting_artificial_gravity.shtml http://www.spacefuture.com/archive/inhabiting_artificial_gra...
- alex_duf 8y ago
  They talk about it in the book, it actually makes some of the characters sick
  - AllegedAlec 8y ago
    Yeah, I know. I just wanted to elucidate for others who may not have read the book what some important reasons are for making rotating ring structures quire large.
alex_duf 8y ago
There's also Medina station which has the massive drum they end up spinning. They then grow crops in it. I love the expanse, such an amazing series of books
- kakarot 8y ago
  Easily my favorite contemporary sci-fi series... but please feel free to change my mind on that.

timbit42 8y ago

A station with a counterweight can be grown into a wheel station. A wheel can be widened until it becomes a tube station.

tomp 8y ago

I agree, except for the availability of resources, a space station makes much more sense than a planetary colony. In addition, all stations depicted are highly sci-fi - a realistic station would have to be modular, to prevent catastrophic failure if anything goes wrong (i.e. at most one module is lost, all the air in the whole station). The up-front costs are way bigger, because you have to manufacture a reinforced floor (which, in case of a planetary colony, is the planet itself) and spin up the station (to provide "gravity"). But operational costs should be much lower, because there is 0 delta-v to get to and from the station (except syncing orbits, which you need to do with a planet as well). Start with two modules tethered in spin, then add additional ones gradually. If we transport the materials from Earth, the cost of initial material is similar to settling on a planet. Once we develop technology for off-world manufacturing, you can literally fly your manufacturing plant to an asteroid, build the station there (with plenty of resources available) and then reposition it however you want. The only kinds of planets that it makes sense to settle, is ones with a magnetosphere - and even that only until we develop other ways of shielding (there are companies working on that - e.g. Talos http://spacetalos.com/ http://spacetalos.com/ )

justanegg 8y ago

you could also build it in space over the course of year and land it on a place with lower gravity than earth easily.