Yes we could. If we can build them at all, that is. This may well be the best place to start, if it's a useful place for them. It was the original plan for the Stanford Torus back in the 1970s, to build it in Earth orbit.
The idea was that the inhabitants would earn a living by building solar power satellites, based on solar mirror concentration of sunlight (they didn't have our modern high efficiency solar photovoltaic panels back then). They predicted that they'd be able to sell electricity to Earth at such a low cost that we'd get all our electricity from space, at a fraction of the present price. If they were right in their calculations - and we'd followed their plans - then our present global warming crisis would never have happened probably.
So anyway, what are the advantages of building such big habitats?
First, it seems likely that small space stations like the ISS and space habs on other moons or planets will always be expensive to build, several orders of magnitude more so than houses on Earth, because of
Imagine if your houses had to be built like submarines to be totally airtight, hold in the air against a vacuum, yet have air that is okay to breath, even though there is no air outside and you can never open a window? And needs to be covered by several meters of shielding over the entire house to keep out radiation? And then imagine if your house has to be replaced by a new house every few decades?
Your colony probably wouldn't last very long unless there was some very compelling economic reason for it.
So with a Stanford Torus, the idea is if you can build a really big habitat,, with lots of space inside, then you have a much higher volume to surface ratio. You still need the same huge amounts of shielding per square meter of habitat - but the same amount of surface area encloses a much larger space.
You can build it with a thick several meters thick layer of shielding, which for a small habitat would mean an impractically large amount of mass per inhabitant - but for a large Stanford Torus with 10,000 inhabitants, say, then it's much more practical.
You have a single environment control system, consisting probably of large areas of plants and crops that grow your food.
So you also get all your own food in space.
You can control the amount of sunlight you get through mirrors, and have any environment you like inside, from the tropics, to the Arctic. You could even emulate the environment of Mars, or Venus or an exoplanet inside if you so wished.
You can spin it to any level of artificial gravity (depending on human spin rate tolerances, currently unknown).
You also have abundant solar power as a source of energy, 24/7, with no night time interruptions.
The other ways we could do this are, with a domed city, or living in a large underground cave (some think the Moon with its low gravity may have lava tube caves ten kilometers in diameter). There's also the possibility of building floating cloud cities in the upper Venus atmosphere.
But a Stanford Torus has many advantages that make it worth considering..
As for the materials, well it is easy to move things around in space. Rather than drive for miles and miles as you do on a planetary surface, you just give it a one off shove in the right direction and let it coast. Or use an ion thruster. Some of th asteroids or the Moon have water that can be used as fuel.
The original plan for the Stanford Torus involved sending a bulldozer to the Moon which would scoop up material, in small chunks, put it into a mass driver, and fire it to the construction site. With the Moon's low escape velocity - compare the size of the lunar module rocket motors with the size of the Saturn V -then it is much easier to supply material from the Moon than from Earth.
Apollo 15: Interplanetary Mountaineers - lunar module photographed from the lunar rover
But to get into orbit from Earth they need a massive rocket like this
Gemini Takes Flight
So if we do build Stanford Torus type habitats in LEO, unless costs to orbit go down hugely (which they might) probably the bulk of the material would come from the Moon or from Near Earth Objects. The shielding at least - that's most of the mass of a Stanford Torus - it can be lunar regolith.
They still need a reason to live there though. With modern technology, then we probably don't need ten thousand people living in orbit in order to build solar power satellites in orbit. We'd use thin film mirrors to concentrate the sunlight, as thin a solar sails. And could probably build the whole thing from Earth via telerobotics and autonomous or semi autonomous robots, with just a few human astronauts "on site".
Similarly for space mining, then it may be largely robotic.
And - likely to still cost more per person to live in space than on the Earth, even with the economic saving of the Stanford Torus. After all we don't need these domes at all on Earth, the air is breathable anyway and the climate is fine for us and the gravity is just right too.
Stanford Torus habitats, or domed cities, or Venus cloud colonies would have to be very very easy to build before it makes economic sense to set up home there instead of building your house on Earth. And same also for growing crops, would need to be very easy to build these space habs for it to be easier to grow crops there than, for instance, in a greenhouse in a desert or a floating "sea city" on the sea, or whatever on the Earth. Far lighter weight construction, climate and atmosphere already fine, far easier to maintain.
Another big unknown I think is how easy it is to maintain these big habitats. Including the mini ecosystem inside, and to keep the crops functioning. And the mirrors, and the vacuum proof shell, air locks, shielding,. machinery, etc.
But if you can build large, almost maintenance free Stanford Torus habitats or lava tube cave habitats, or domed cities, or floating cloud colonies, any of these - then it's a one off cost. You need some economic incentive to build it in the first place. But once done, it would then be a place to live into the indefinite future, and cost not that much different from housing on Earth, which also have on-going maintenance costs, e.g. for roads,lighting, utilities, etc.
Probably the design would be refined in many ways. The original Stanford Torus had the shielding against cosmic radiation non rotating with the habitat spinning inside the shielding as an inner sleeve with relative velocity of around 200 mph.
The problem is that 4.5 tons per square meter of shielding is difficult to engineer for when it is under full gravity. Their solution - no need to spin the shielding, just the habitat itself.
That doesn't seem impossible - after all we have 200 mph maglev trains etc. Modern ideas however tend to spin the shielding along with the interior shell of the habitat. We don't have any materials strong enough to stand up to this, so instead they use thousands of stays, like a suspension bridge, but that clutters up the open space inside the habitat. Also tend to be multi-layer - if you have built your habitat then why just have one "floor area" inside? The result is easier engineering and more living space - though you don't have the same high ceilings and long vistas of the original 'Stanford Torus design.
I think another possible refinement might be to spin the whole structure much more slowly, at a thousandth of a g - the reasoning is that the interior is going to be used mainly for growing plants. And plants probably don't need full g, and a thousandth of a g might well be adequate. If so, design it for plants - eliminates all those stays as the shielding now still has a mass of 4.5 tons per square meter, but its weight is only 4.5 kgs per square meter, much easier to engineer around. Or a hundredth of a g and 45 kgs per square meter, whatever it is that it turns out is optimal for plant growth. And within it humans can live either in an inner "maglev train" type sleeve that spins within the habitat with the plants - like the original idea except that it is only used for the regions humans live in - or in smaller spinning cots inside their houses where they sleep at night - or whatever else works best depending on human spin tolerances and how much artificial gravity we need.
For more about this:
Asteroid Resources Could Create Space Habs For Trillions; Land Area Of A Thousand Earths
The idea was that the inhabitants would earn a living by building solar power satellites, based on solar mirror concentration of sunlight (they didn't have our modern high efficiency solar photovoltaic panels back then). They predicted that they'd be able to sell electricity to Earth at such a low cost that we'd get all our electricity from space, at a fraction of the present price. If they were right in their calculations - and we'd followed their plans - then our present global warming crisis would never have happened probably.
So anyway, what are the advantages of building such big habitats?
First, it seems likely that small space stations like the ISS and space habs on other moons or planets will always be expensive to build, several orders of magnitude more so than houses on Earth, because of
- need to contain the pressure of the air at tons per square meter outwards pressure, and to make all their own oxygen to breath,
- environmental regulation of harmful gases that build up in them and microbes etc.
- The damaging environment of space with its vacuum conditions, radiation, micrometeorites etc. The ISS modules only last a few decades before they need to be replaced or de-orbit.
- Needs protection from cosmic radiation and solar storms.
Imagine if your houses had to be built like submarines to be totally airtight, hold in the air against a vacuum, yet have air that is okay to breath, even though there is no air outside and you can never open a window? And needs to be covered by several meters of shielding over the entire house to keep out radiation? And then imagine if your house has to be replaced by a new house every few decades?
Your colony probably wouldn't last very long unless there was some very compelling economic reason for it.
So with a Stanford Torus, the idea is if you can build a really big habitat,, with lots of space inside, then you have a much higher volume to surface ratio. You still need the same huge amounts of shielding per square meter of habitat - but the same amount of surface area encloses a much larger space.
You can build it with a thick several meters thick layer of shielding, which for a small habitat would mean an impractically large amount of mass per inhabitant - but for a large Stanford Torus with 10,000 inhabitants, say, then it's much more practical.
You have a single environment control system, consisting probably of large areas of plants and crops that grow your food.
So you also get all your own food in space.
You can control the amount of sunlight you get through mirrors, and have any environment you like inside, from the tropics, to the Arctic. You could even emulate the environment of Mars, or Venus or an exoplanet inside if you so wished.
You can spin it to any level of artificial gravity (depending on human spin rate tolerances, currently unknown).
You also have abundant solar power as a source of energy, 24/7, with no night time interruptions.
The other ways we could do this are, with a domed city, or living in a large underground cave (some think the Moon with its low gravity may have lava tube caves ten kilometers in diameter). There's also the possibility of building floating cloud cities in the upper Venus atmosphere.
But a Stanford Torus has many advantages that make it worth considering..
- Sunlight available 24/7
- Gravity can be customized to whatever level is best for human health
- You can position your habitat anywhere you like in space, not limited to the surfaces of planets or moons
- Resources abundant from NEOs, or the Moon.
As for the materials, well it is easy to move things around in space. Rather than drive for miles and miles as you do on a planetary surface, you just give it a one off shove in the right direction and let it coast. Or use an ion thruster. Some of th asteroids or the Moon have water that can be used as fuel.
The original plan for the Stanford Torus involved sending a bulldozer to the Moon which would scoop up material, in small chunks, put it into a mass driver, and fire it to the construction site. With the Moon's low escape velocity - compare the size of the lunar module rocket motors with the size of the Saturn V -then it is much easier to supply material from the Moon than from Earth.
But to get into orbit from Earth they need a massive rocket like this
So if we do build Stanford Torus type habitats in LEO, unless costs to orbit go down hugely (which they might) probably the bulk of the material would come from the Moon or from Near Earth Objects. The shielding at least - that's most of the mass of a Stanford Torus - it can be lunar regolith.
They still need a reason to live there though. With modern technology, then we probably don't need ten thousand people living in orbit in order to build solar power satellites in orbit. We'd use thin film mirrors to concentrate the sunlight, as thin a solar sails. And could probably build the whole thing from Earth via telerobotics and autonomous or semi autonomous robots, with just a few human astronauts "on site".
Similarly for space mining, then it may be largely robotic.
And - likely to still cost more per person to live in space than on the Earth, even with the economic saving of the Stanford Torus. After all we don't need these domes at all on Earth, the air is breathable anyway and the climate is fine for us and the gravity is just right too.
Stanford Torus habitats, or domed cities, or Venus cloud colonies would have to be very very easy to build before it makes economic sense to set up home there instead of building your house on Earth. And same also for growing crops, would need to be very easy to build these space habs for it to be easier to grow crops there than, for instance, in a greenhouse in a desert or a floating "sea city" on the sea, or whatever on the Earth. Far lighter weight construction, climate and atmosphere already fine, far easier to maintain.
Another big unknown I think is how easy it is to maintain these big habitats. Including the mini ecosystem inside, and to keep the crops functioning. And the mirrors, and the vacuum proof shell, air locks, shielding,. machinery, etc.
But if you can build large, almost maintenance free Stanford Torus habitats or lava tube cave habitats, or domed cities, or floating cloud colonies, any of these - then it's a one off cost. You need some economic incentive to build it in the first place. But once done, it would then be a place to live into the indefinite future, and cost not that much different from housing on Earth, which also have on-going maintenance costs, e.g. for roads,lighting, utilities, etc.
Probably the design would be refined in many ways. The original Stanford Torus had the shielding against cosmic radiation non rotating with the habitat spinning inside the shielding as an inner sleeve with relative velocity of around 200 mph.
The problem is that 4.5 tons per square meter of shielding is difficult to engineer for when it is under full gravity. Their solution - no need to spin the shielding, just the habitat itself.
That doesn't seem impossible - after all we have 200 mph maglev trains etc. Modern ideas however tend to spin the shielding along with the interior shell of the habitat. We don't have any materials strong enough to stand up to this, so instead they use thousands of stays, like a suspension bridge, but that clutters up the open space inside the habitat. Also tend to be multi-layer - if you have built your habitat then why just have one "floor area" inside? The result is easier engineering and more living space - though you don't have the same high ceilings and long vistas of the original 'Stanford Torus design.
I think another possible refinement might be to spin the whole structure much more slowly, at a thousandth of a g - the reasoning is that the interior is going to be used mainly for growing plants. And plants probably don't need full g, and a thousandth of a g might well be adequate. If so, design it for plants - eliminates all those stays as the shielding now still has a mass of 4.5 tons per square meter, but its weight is only 4.5 kgs per square meter, much easier to engineer around. Or a hundredth of a g and 45 kgs per square meter, whatever it is that it turns out is optimal for plant growth. And within it humans can live either in an inner "maglev train" type sleeve that spins within the habitat with the plants - like the original idea except that it is only used for the regions humans live in - or in smaller spinning cots inside their houses where they sleep at night - or whatever else works best depending on human spin tolerances and how much artificial gravity we need.
For more about this:
Asteroid Resources Could Create Space Habs For Trillions; Land Area Of A Thousand Earths
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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