Living away from earth (split from Mars gravity issue)

[mistermack]

16 hours ago, Endy0816 said:

Stints in artificial gravity may be enough though for the initial colonization effort.

Jupiter will be the real challenge.

I've posted this before, but I still believe that the future of humans away from the Earth is in space stations, not planets or moons. Once you get them up to a certain size, you can rotate them and create 1g of artificial gravity, you have virtually limitless free energy beaming at you, and you can land and take off using practically no fuel whatsoever. You can mine the moons for raw materials, you can use the cheap solar electricity to manufacture everything, you have free cold storage, and space is well and truly limitless. 

Here on Earth, we are running out of space with seven billion humans. Up there, there is room for seven billion billion humans, without stepping on each others toes. That is by living on space stations.

I would imagine that the first stage in colonising space would be a Moon mining operation, with a space station orbiting the Moon as permanent living quarters. I don't think Mars or the outer planets would become any use for hundreds of years. The first step would be to establish a settlement that was self-sustaining without help from Earth. And that's a formidable step, but should happen within a couple of hundred years.

[beecee]

22 minutes ago, mistermack said:

I've posted this before, but I still believe that the future of humans away from the Earth is in space stations, not planets or moons.

I've heard that suggested in "cloud cities" about 50 kms up orbiting Venus.

https://en.wikipedia.org/wiki/Colonization_of_Venus

[Endy0816]

8 hours ago, mistermack said:

I've posted this before, but I still believe that the future of humans away from the Earth is in space stations, not planets or moons. Once you get them up to a certain size, you can rotate them and create 1g of artificial gravity, you have virtually limitless free energy beaming at you, and you can land and take off using practically no fuel whatsoever. You can mine the moons for raw materials, you can use the cheap solar electricity to manufacture everything, you have free cold storage, and space is well and truly limitless. 

Here on Earth, we are running out of space with seven billion humans. Up there, there is room for seven billion billion humans, without stepping on each others toes. That is by living on space stations.

I would imagine that the first stage in colonising space would be a Moon mining operation, with a space station orbiting the Moon as permanent living quarters. I don't think Mars or the outer planets would become any use for hundreds of years. The first step would be to establish a settlement that was self-sustaining without help from Earth. And that's a formidable step, but should happen within a couple of hundred years.

Do agree on space stations, though figure people will want to establish Surface Colonies anyways. Tourist destinations, research outposts, religious groups and homesteaders. Best approach is likely to have first established at least a rudimentary space station for that body ironically.

Do think non-rotating stations are likely to be more typical, but either way is good.

Jupiter and it's moons just offer ridiculous amounts of easy resources. The magnetic fields out that way may also be useful.

Edited January 12, 2022 by Endy0816

[mistermack]

11 hours ago, beecee said:

I've heard that suggested in "cloud cities" about 50 kms up orbiting Venus.

I've heard that too. It's a possibility, but I would say that it's not likely to be first or second choice, because with the current technology, there's very little to be gained on Venus. It's too hot on the surface, and there's not much that's useable in the atmosphere, which is also very corrosive. 

Venus would be a great candidtate for Terraforming, having close to 1g gravity. But it would be an enormous project. Probably far too much for the available gains. 

4 hours ago, Endy0816 said:

Jupiter and it's moons just offer ridiculous amounts of easy resources. The magnetic fields out that way may also be useful.

I don't think Jupiter itself would have any useable resources, but it's moons would. Our own Moon would be easier to exploit though, because the sunlight is stronger here, so power generation is easier. 

[TheVat]

18 hours ago, mistermack said:

I've posted this before, but I still believe that the future of humans away from the Earth is in space stations, not planets or moons. Once you get them up to a certain size, you can rotate them and create 1g of artificial gravity, you have virtually limitless free energy beaming at you, and you can land and take off using practically no fuel whatsoever....

How would you shield them from cosmic rays and solar proton events?  On earth, we have a magnetic field and atmosphere to shield us.  We get around 0.4 mSv (millisieverts) annually, compared to 150 in LEO, and 400-2000 in deep space.   Not a good situation for any longterm residents.  Given Mars lack of magnetosphere, surface dwellers would also have to deal with this, which could make musculoskeletal atrophy look like a fairly minor problem.

[mistermack]

8 hours ago, TheVat said:

How would you shield them from cosmic rays and solar proton events? 

To begin with, you could, as now, have the first space stations orbiting within the Earth's protective shield. Then later, as stations got bigger, you could have the plant-growing surfaces situated on the outside facing in, so that the moist soil would be absorbing the harmful stuff. Obviously, that would be way down the line, on huge self sustaining space stations. Anything bulky that needs storing, like the water supply, could also be positioned on the outer surface. 

Maybe a station could generate it's own magnetic shield, a mini version of the Earth.

[Ken Fabian]

I'd go for an asteroid/space station combination or perhaps spinning habitats within asteroids - constructed using refined iron and steels (byproduct of refining Nickel and mixed Platinum Group Metals for export) as well as unrefined nickel-iron that is available in extraordinary abundance.

I'm not sure the Moon or Mars will have anything that a well chosen asteroid or perhaps a Mars moon wouldn't. Earth however, will be the source of much that is essential.

[mistermack]

It's an interesting thought, the engineering of a spinning space station. On earth, the main building materials need to be strong in compression, whereas in a spinning space station, you want materials that are strong in tension. The lack of weather should be a plus, and storage space will be limitless, and heavy lifting will be very different. 

[swansont]

Why would storage space be limitless on a space station? 

[Ken Fabian]

3 hours ago, swansont said:

Why would storage space be limitless on a space station? 

Perhaps that would be limitless storage space near a space station? Still could be a LOT of room towards the core if the principle living and working spaces are near the circumference for pseudo-gravity.

I don't know how heavy the construction can get with materials like nickel-iron and hold together when spun up but it seems clear that to dodge the cosmic rays/solar wind it needs to be a lot thicker walled than we usually think of for space construction.

[beecee]

Question: What would the diameter of a space station orbiting Earth need to be to create 1G effects at the circumference/perimeter? And what would be the nominal orbital parameter? 

(I vaguely remember reading/hearing that the actual size needed would make such a venture impractical.)

[Genady]

12 minutes ago, beecee said:

Question: What would the diameter of a space station orbiting Earth need to be to create 1G effects at the circumference/perimeter?

Do you mean a station is spinning to create 1G at the circumference? Then, acceleration of a circular motion is v²/R. Equate it to 1G and find R for a given v.

[swansont]

12 hours ago, Genady said:

Do you mean a station is spinning to create 1G at the circumference? Then, acceleration of a circular motion is v²/R. Equate it to 1G and find R for a given v.

You also want the gradient to be acceptable as you move toward the rim, or you'd end up with a situation where you had 1g at your feet but significantly less at your head. (consider a 2m radius, for example)

[Genady]

24 minutes ago, swansont said:

You also want the gradient to be acceptable as you move toward the rim, or you'd end up with a situation where you had 1g at your feet but significantly less at your head. (consider a 2m radius, for example)

Right. Back of a very tiny envelope calculation shows that to have a drop in acceleration 1% over 10 m the radius needs to be 1 km.

Here comes the real question: How do I type Greek letters here?  I wanted to put 'omega' for the angular velocity...

[mistermack]

21 hours ago, beecee said:

Question: What would the diameter of a space station orbiting Earth need to be to create 1G effects at the circumference/perimeter? And what would be the nominal orbital parameter? 

(I vaguely remember reading/hearing that the actual size needed would make such a venture impractical.)

That's been calculated many times. The limiting factor is the effect on the inner ear, causing nausea for some people. From memory, the answer is 224 metres. At that size, an orbital period of 30 seconds gives 1g artificial gravity, and no humans experience nausea. 

You could go lower than 224m and experiment with drugs for the people who feel nauseous, or go for slightly less than 1g, so the 224m isn't a fixed point, but anything over that would be ok. 

That sounds like a big space station, but it could be just two balanced units, with a 224 metre tether, rotating opposite each other. But anyway, in the distant future, it's likely that 224 metres would be on the small side. If a station is to be self-sustaining, it would have to be a lot bigger than that. 

So long term, I don't think size will be any kind of obstacle. But short term, it will be. 

[DaviBrons]

I believe that the most important thing in space exploration (colonization of other planets or life in orbital stations) will be the security dilemma and the policy of containment. In simple words, with the development of technology, weapons potential will also develop. Moreover, during space exploration, new civilizations may be discovered, with which conflicts may also arise. And I am sure that weapons of mass destruction will be the main weapons of the future.

[Airbrush]

On 1/14/2022 at 1:32 PM, mistermack said:

That's been calculated many times. The limiting factor is the effect on the inner ear, causing nausea for some people. From memory, the answer is 224 metres. At that size, an orbital period of 30 seconds gives 1g artificial gravity, and no humans experience nausea. 

You could go lower than 224m and experiment with drugs for the people who feel nauseous, or go for slightly less than 1g, so the 224m isn't a fixed point, but anything over that would be ok. 

That sounds like a big space station, but it could be just two balanced units, with a 224 metre tether, rotating opposite each other. But anyway, in the distant future, it's likely that 224 metres would be on the small side. If a station is to be self-sustaining, it would have to be a lot bigger than that. 

So long term, I don't think size will be any kind of obstacle. But short term, it will be. 

That sounds like a good idea.  You start with "two balanced units, with a 224 meter tether."  Then you can add more balanced units, two at a time.  Over time many more pairs of balanced units can be added.  It would be nice to park your rotating space station near an asteroid that has water ice, to create air, water, and fuel.  The crew work an 8-hour shift in zero g, then take a space elevator to the space station, where they can sleep and recreate in one g for 16 hours.  Even exploring Mars or the Moon, it would be better to have living quarters in a space station, orbiting the planet or moon.

Edited February 17, 2022 by Airbrush

[mistermack]

49 minutes ago, Airbrush said:

Even exploring Mars or the Moon, it would be better to have living quarters in a space station, orbiting the planet or moon.

It wouldn't be that simple, even on the Moon. It doesn't take too much energy to take off from the Moon, but a space station would have to be in Moon orbit, so you would have to accelerate to get on, and then decelerate on the return trip. Mars would be a major undertaking, landing and taking off, involving a great amount of energy. Not something you could afford to do on a daily basis. But Mars does have a couple of small moons that would be very interesting from a materials point of view. 

[Airbrush]

On 2/17/2022 at 11:34 AM, mistermack said:

It wouldn't be that simple, even on the Moon. It doesn't take too much energy to take off from the Moon, but a space station would have to be in Moon orbit, so you would have to accelerate to get on, and then decelerate on the return trip. Mars would be a major undertaking, landing and taking off, involving a great amount of energy. Not something you could afford to do on a daily basis. But Mars does have a couple of small moons that would be very interesting from a materials point of view. 

"A space elevator is a proposed type of planet-to-space transportation system.^[1] The main component would be a cable (also called a tether) anchored to the surface and extending into space. The design would permit vehicles to travel along the cable from a planetary surface, such as the Earth's, directly into orbit, without the use of large rockets. An Earth-based space elevator would consist of a cable with one end attached to the surface near the equator and the other end in space beyond geostationary orbit (35,786 km altitude)."

https://en.wikipedia.org/wiki/Space_elevator

If a space elevator could be constructed on Earth, it could also be done on the Moon, Mars, or any other moon in our solar system.  If the space station was parked near an asteroid, with a tether between your one-g rotating space station, the gravity is so low that transport between work and home would be a short commute.

Edited February 19, 2022 by Airbrush

[Ken Fabian]

On 2/18/2022 at 5:31 AM, Airbrush said:

Then you can add more balanced units, two at a time.

Two objects tethered together will be intrinsically stable rotating around a shared axis. More than two will be unstable. Not impossible to have more but active control of some sort would be essential. Rigid structures would defeat the purpose of reducing structural requirements.

 

On 2/18/2022 at 5:31 AM, Airbrush said:

Even exploring Mars or the Moon, it would be better to have living quarters in a space station, orbiting the planet or moon.

The engineering challenges for building a rotating structure for pseudo-gravity on - or perhaps in - Mars or Moon (or an asteroid) probably aren't that much greater than building in space, but engineering the transport system to commute between orbit and Mars or Moon will greatly increase the overall difficulties. For asteroids that part would be easier but building inside an asteroid would give plenty of radiation shielding, which a station would have to carry as mass.

Asteroids at least offer the potential for trade in bulk physical commodities, which Mars and Moon do not. But to get across the line and be economically viable I expect any attempts to mine asteroids will be based around remote robotics and will ruthless in eliminating any unnecessary dependence on astronauts. The economics are not incidental - for grand space dreams like permanent, independent human habitation commercial profitability based on sound business plans look essential to me.

Edited February 19, 2022 by Ken Fabian

[Airbrush]

2 hours ago, Ken Fabian said:

Two objects tethered together will be intrinsically stable rotating around a shared axis. More than two will be unstable. Not impossible to have more but active control of some sort would be essential. Rigid structures would defeat the purpose of reducing structural requirements.

The engineering challenges for building a rotating structure for pseudo-gravity on - or perhaps in - Mars or Moon (or an asteroid) probably aren't that much greater than building in space, but engineering the transport system to commute between orbit and Mars or Moon will greatly increase the overall difficulties. For asteroids that part would be easier but building inside an asteroid would give plenty of radiation shielding, which a station would have to carry as mass.

Asteroids at least offer the potential for trade in bulk physical commodities, which Mars and Moon do not. But to get across the line and be economically viable I expect any attempts to mine asteroids will be based around remote robotics and will ruthless in eliminating any unnecessary dependence on astronauts. The economics are not incidental - for grand space dreams like permanent, independent human habitation commercial profitability based on sound business plans look essential to me.

I don't see why you could not add living modules 2 at a time.  It would be like constructing a merri-go-round while it is spinning.  The tethers between two sets of balanced modules intersect at a hub point.  At the hub the length of tethers may be adjusted to perfectly balance the 2.

I like the idea of hollowing out an asteroid.  You are creating a habitable void inside as you extract valuable minerals and water-ice.  Then after you build a base inside the asteroid you have retro rockets get it spinning so those living inside would have one g as they stand with their heads pointing towards the center of the asteroid, AND they are protected by rock shielding.

[mistermack]

On 2/19/2022 at 3:26 AM, Airbrush said:

A space elevator is a proposed type of planet-to-space transportation system

The logistics of a space elevator make it a pretty unrealistic prospect. It's an attractive idea, but the materials don't exist to build one, as yet.  The very best modern materials would be far too heavy, and the forces imposed on it by the weather would also rule one out, here on Earth, and probably Mars too, to a lesser extent. 

It would be less of a challenge on the Moon, but then, taking off from the Moon by rocket isn't much of a challenge either.  

On the Moon, it would be feasible to fire materials up into orbit from a big gun, or using a linear electric accelerator up an inclined track, the lack of drag and low gravity would make it feasible. People could lift off more gently in a small rocket, like the Lunar Astronauts did. 

[Airbrush]

On 2/21/2022 at 7:39 AM, mistermack said:

The logistics of a space elevator make it a pretty unrealistic prospect. It's an attractive idea, but the materials don't exist to build one, as yet.  The very best modern materials would be far too heavy, and the forces imposed on it by the weather would also rule one out, here on Earth, and probably Mars too, to a lesser extent. 

It would be less of a challenge on the Moon, but then, taking off from the Moon by rocket isn't much of a challenge either.  

On the Moon, it would be feasible to fire materials up into orbit from a big gun, or using a linear electric accelerator up an inclined track, the lack of drag and low gravity would make it feasible. People could lift off more gently in a small rocket, like the Lunar Astronauts did. 

That is interesting.  It looks like the lower the mass, the easier it is to build and use.  Too difficult on Earth, maybe even Mars, but the moon and asteroids are possible places to park a one-g space station with an elevator attached to the moon or asteroid.

"Because of the Moon's lower gravity and lack of atmosphere, a lunar elevator would have less stringent requirements for the tensile strength of the material making up its cable than an Earth-tethered cable. An Earth-based elevator would require high strength-to-weight materials that are theoretically possible, but not yet fabricated in practice (e.g., carbon nanotubes). A lunar elevator, however, could be constructed using commercially available mass-produced high-strength para-aramid fibres (such as Kevlar and M5) or ultra-high-molecular-weight polyethylene fibre.

"Compared to an Earth space elevator, there would be fewer geographic and political restrictions on the location of the surface connection. The connection point of a lunar elevator would not necessarily have to be directly under its center of gravity, and could even be near the poles, where evidence suggests there might be frozen water in deep craters that never see sunlight; if so, this might be collected and converted into rocket fuel."

Lunar space elevator - Wikipedia

 

[Dropship]

On 1/12/2022 at 1:00 AM, mistermack said:

..The first step would be to establish a settlement that was self-sustaining without help from Earth. And that's a formidable step, but should happen within a couple of hundred years.

 

Could a colony on the moon or mars really survive without earth backing them up?

Presumably they'd have to live under domes, replenishing air, water and food etc?

Edited March 16, 2022 by Dropship

[zapatos]

On 3/16/2022 at 12:25 PM, Dropship said:

Could a colony on the moon or mars really survive without earth backing them up?

 

I don't see why not. What obstacles do you think can not be overcome?