Could Mars be partially terraformed, then Marsform humans to live with the results?

[Noclevername]

Do you think people will want that so much that they'd want to live in space instead of planet-side? Not me. If I want to experience free fall, I'll visit space, but I don't think I'd want to live there.

Personally I'd love the idea of stepping out of bed, taking an elevator to 1/10th g, putting on a pair of wings and flying. Then back home for a full g shower.

[potoole]

Terra form Mars as much as possible, or live in protective domes, or both. I think humans will just have to acquire the ability to live on a surface with less than Earth's gravity. Who knows, future technology could make that possible.

Nonetheless, this creamy wild rice soup is pretty good.

PO'T

[cjameshuff]

That's an argument for putting solar power stations in space not for living in space. As for living, if peeps have a similar diurnal pattern on Mars as they do on earth, peak load will be at peak solar generation. Although I'd expect them to quickly go to nuclear power.

Putting solar arrays in space and living on the ground makes for certain obvious issues in getting the produced power to those people. Nuclear power is clearly a better option for large power needs on the ground, but it isn't so clear in space.

If people want a gravity lower than on Mars. If they want higher, there is spinning available.

People constructing solar arrays do want gravity lower than Mars. Zero is just perfect. Spinning can't provide that on the ground.

Outside of any type of atmospheric planetary/moon-ary habitat. Inside the habitat/home they'd have dust from shed skin, clothing and possessions and fungus and all the other things that create dust everywhere humans live.

...why would they put their solar panels inside?

Some people like their ceilings to be opaque. In a spinning habitat in space, there probably won't even be a ceiling that can look to space.

I have no idea why you're going on about opaque ceilings.

We're talking about living, not traversing.

The two are inseparably related. People need access to transport for themselves and for goods.

Do you think people will want that so much that they'd want to live in space instead of planet-side? Not me. If I want to experience free fall, I'll visit space, but I don't think I'd want to live there.

They very well may. Apart from the recreational possibilities of a freefall/microgravity area, there are many industrial possibilities in space.

I like weather. It's one of the main reasons why I want to live on a planet.

Oh, how would people live without being able to tromp through dust storms? And frigid winds! And a little snow, and maybe even some freezing rain!

Does mars have quakes? (ignoring the earth-centricity of the statement )

It seems pretty thoroughly dead compared to Earth, but I'd expect plenty of quakes from ground settling as water and CO2 deposits are vaporized, and a lot of major landslides and such as the landscape is exposed to new temperatures, atmosphere, and moisture levels, and other human activities intended to extract gas from rocks or prevent it from being absorbed by them.

They won't have to be inside all the time even if not terraformed. And the planet-side structures can be built much differently. If it's terraformed then they may not even need a p-suit. Some people like having vistas and weather and go for walks outside under their own power and maybe even feel the wind in their hair.

They can and would certainly choose to get all that in an enclosed park. I think very, very few people will prefer to live on a planet because they can bundle up in thick insulation and oxygen mask and wander around a desolate wasteland with nothing but rocks, dust, and a few genetically-engineered lichens...especially when the alternative is living somewhere where you could spend your vacations on trips to a variety of such wastelands and one garden world, and spend your weekends in parks and greenhouses, ranging from those indistinguishable from a planetary example, to works of microgravity art and architecture that surface dwellers travel to the habitats to visit on their vacations.

Maybe, depends on how much weight or force is on those bearings (assuming they're not magnetic or fluid). A rotating habitat in space may also need heavily loaded wearings if it spins inside a non-rotating protective shield. If the shield also rotates then you're adding to the stress on the cross-members and hoop and complicating the docking system and creating a greater hazard to other space traffic in the event of a structural failure (flywheel explosion). It might be worth the investment for temporary abodes for transit and vacation or employment deployments, but for settling down to have a family?

Bearings that carry a load will be more expensive than bearings that do not carry a load. And structures in space do not need to handle anything like the loads of structures on a planetary surface. And are you seriously using the risk of habitats flying apart as a reason not to live in space? Groundside caverns can collapse, foundations can fail, etc. Just don't live somewhere with such shoddy construction.

A spinning habitat on a planet might have atmospheric loses, but how much would that be? Can you quantify for us how much energy would be lost in the friction of a rotating disc with the atmosphere?

We're talking huge structures with bullet-train airspeeds at the outer surface. Losses would be large, compared to zero for orbital habitats.

On the plus side, the rotating habitat on a planet can vary speed and stop much more easily due to its ability to transfer momentum to a much larger and relatively stationary object. The ability to vary the habitat's enveloping atmosphere also allows repairs and construction to progress more easily. It can also have a thicker radiation/thermal shield for less investment. It can also have local solar or nuclear power with less complexity. This is assuming people living on the planet even want or need a rotating habitat.

Rotating habitats in orbit can be constructed with net zero angular momentum, making them just as easy to stop. No advantage to Mars.

You could likely pressurize work areas in orbit to degrees similar to those outside Mars habitats without too much trouble, and orbital habitats also have access to arbitrarily low gravity. The repair/maintenance advantage is on the side of orbital habitats.

Lack of a gravity field means orbital habitats would have cheaper shielding, not Mars surface ones.

Martian solar power is vastly more complex...sun tracking, nighttime periods, dust and weather, all the various issues I've already raised. Nuclear power...only minor differences, the atmosphere being too thin to be a really useful heat sink. Both will need large radiators. Radiators on Mars won't be able to avoid the sun and Mars itself.

I wouldn't worry about it, "lunarforming" is probably the least likely scenario to gain support. For one thing, we already have a Moon with those qualities-- along with most of the bodies in the Solar System, which are all more vacuum-y than even a fully frozen Mars could be. Many are also easier to reach, have less gravity and some have more volatiles per volume than Mars. If we're going to put such a massive industrial effort into Mars, it'll be to make it more Earthlike, not less.

I really doubt that. You can't make it Earthlike enough for that to be anything but a tremendous waste of natural resources in the long run, while also being horribly expensive in the short term. In comparison, an operation to freeze out CO2 provides a useful raw material while working to reduce the transport costs involved in the export of CO2, water, etc.

Terraforming: a huge investment required to accomplish anything with negative payoff due to the increases in atmospheric hazards and loss of concentrated deposits of volatiles.
Lunaforming: likely immediate profit, or at least very low cost compared to the massive industry needed for terraforming (a simple shade fence near a pole could keep a lot of CO2 frozen), leading to future reduced costs.

And yeah, there are other airless bodies in the solar system...and lunaforming would let you use technologies developed for them on Mars, while gaining access to the things Mars has that they generally will lack...minerals concentrated and processed by ancient liquid water, for example.

[Noclevername]

I really doubt that. You can't make it Earthlike enough for that to be anything but a tremendous waste of natural resources in the long run, while also being horribly expensive in the short term.

How do you know how Earthlike it can be made? We don't even know how much ice it has altogether.

Terraforming: a huge investment required to accomplish anything with negative payoff due to the increases in atmospheric hazards and loss of concentrated deposits of volatiles.

But a positive "payoff" in fulfilling the desires of terraformers. I don't know of anyone but you who wants the opposite.

EDIT: I did google up just one entry for it, at Lunarpedia. It was the only entry I found. I guess someone who likes the conditions of the Moon is already looking to annex territory.

Lunaforming: likely immediate profit, or at least very low cost compared to the massive industry needed for terraforming (a simple shade fence near a pole could keep a lot of CO2 frozen), leading to future reduced costs.

Quite an optomistic assessment, I'll give you that.

Again, "cost" and "profit" depends on what your goals are. Mars is still at the bottom of a fairly steep gravity well, so I doubt that mining for export will be its main attraction.

And yeah, there are other airless bodies in the solar system...and lunaforming would let you use technologies developed for them on Mars, while gaining access to the things Mars has that they generally will lack...minerals concentrated and processed by ancient liquid water, for example.

And yet, processes developed for asteroids will still be useful on millions of asteroids.

[Noclevername]

We're talking about living, not traversing.

Nomads on Earth have been combining both for millenia. With a mobile space habitat, you can travel and bring your whole neighborhood with you!

[Noclevername]

Lunaforming: likely immediate profit, or at least very low cost compared to the massive industry needed for terraforming (a simple shade fence near a pole could keep a lot of CO2 frozen), leading to future reduced costs.

Aeroscooping Mars could provide CO2 for less cost and industrial effort than freezing it out and shipping it up from the surface.

[cjameshuff]

Aeroscooping Mars could provide CO2 for less cost and industrial effort than freezing it out and shipping it up from the surface.

Debatable. Collecting gas while passing through the atmosphere at orbital velocity is not trivial, and will involve applying a lot of delta-v to a given mass of vehicle for the amount of gas collected. It may well be easier to ship up solid CO2, liquid nitrogen, etc from the surface, especially if you can use mass drivers and such. (or if you can manage the materials, space elevators)

[Noclevername]

Debatable. Collecting gas while passing through the atmosphere at orbital velocity is not trivial, and will involve applying a lot of delta-v to a given mass of vehicle for the amount of gas collected. It may well be easier to ship up solid CO2, liquid nitrogen, etc from the surface, especially if you can use mass drivers and such. (or if you can manage the materials, space elevators)

If you combine the major industrial efforts needed for Lunaforming and building a Mars-surface mass driver, it adds up to a lot. Meanwhile a space-based society could mass-produce drone scoop-divers, and if they lose a few it's not a major financial catastrophy.

You also would have to fight terraformers who will be sabotaging your efforts if not leading to outright war. Remember, they outnumber lunaformers by... well, all of them. The idea of terraforming Mars is in some ways more popular than colonizing it.

[Ara Pacis]

Putting solar arrays in space and living on the ground makes for certain obvious issues in getting the produced power to those people. Nuclear power is clearly a better option for large power needs on the ground, but it isn't so clear in space.

Which is why it's not my preference for primary power on Mars. You could do it, but I think it's too much hassle except for small and/or isolated loads.

People constructing solar arrays do want gravity lower than Mars. Zero is just perfect. Spinning can't provide that on the ground.

...why would they put their solar panels inside?

I have no idea why you're going on about opaque ceilings.

You were talking about solar panels here? I was talking about people and general use.

The two are inseparably related. People need access to transport for themselves and for goods.

Not necessarily. Lots of people commute to jobs for a season and then go back home. Not all migrant workers are lettuce pickers, some work on oil rigs, some drive on ice road, some fish the Bering Sea some play poker in the torpedo room when no one's around because their bored and hope they'll stay that way.

They very well may. Apart from the recreational possibilities of a freefall/microgravity area, there are many industrial possibilities in space.

And there's tele-commuting/tele-presense/tele-robotics for a lot of that. Lightspeed lag may still require someone in a hab within a couple AU but will it be a civilization's worth of population?

Oh, how would people live without being able to tromp through dust storms? And frigid winds! And a little snow, and maybe even some freezing rain!

I know Teddy Roosevelt was looked at strangely when he set up the National Park system for that sorta thing. And Edmund Hillary, what a weirdo.

It seems pretty thoroughly dead compared to Earth, but I'd expect plenty of quakes from ground settling as water and CO2 deposits are vaporized, and a lot of major landslides and such as the landscape is exposed to new temperatures, atmosphere, and moisture levels, and other human activities intended to extract gas from rocks or prevent it from being absorbed by them.

Well, we deal with it on Earth, so maybe we can deal with it on Mars.

They can and would certainly choose to get all that in an enclosed park. I think very, very few people will prefer to live on a planet because they can bundle up in thick insulation and oxygen mask and wander around a desolate wasteland with nothing but rocks, dust, and a few genetically-engineered lichens...especially when the alternative is living somewhere where you could spend your vacations on trips to a variety of such wastelands and one garden world, and spend your weekends in parks and greenhouses, ranging from those indistinguishable from a planetary example, to works of microgravity art and architecture that surface dwellers travel to the habitats to visit on their vacations.

A lot of people like to visit the Grand Canyon, Niagara Falls, Pikes Peak, Yellowstone, glaciers, etc --people are strange, eh? Some people even build houses with windows so that they can look out their window just to see certain rocks. Go figure. Oh, but microgravity/spinning-hab greenhouses and parks will be distinguishable from planet-side gardens, parks and greenhouses because of the Coriolis effect and radial configuration.

Bearings that carry a load will be more expensive than bearings that do not carry a load. And structures in space do not need to handle anything like the loads of structures on a planetary surface. And are you seriously using the risk of habitats flying apart as a reason not to live in space? Groundside caverns can collapse, foundations can fail, etc. Just don't live somewhere with such shoddy construction.

I think you're over-estimating the loads on a planetary habitat that's spinning and underestimating the possible loads on rotating habs in space. You don't even need bearings in space if everything rotates as one item, but then you'll have difficulty with alignment for solar panels, communications antenna/dishes, telescopes, and spacecraft that bring supplies and passengers will have to perform ballet.

We're talking huge structures with bullet-train airspeeds at the outer surface. Losses would be large, compared to zero for orbital habitats.

Are you referring to what Noclevername mentioned earlier? You don't need a bullet train in order to go 43 MPH. That's assuming people can deal with 3 RPMs. If they prefer 2 RPMs then the speed will need to increase to 64 MPH, and the rotating portion of the habitat would increase in size too. Of course, only the outer-most portion of the spinning disc would move at that speed. The closer the surface of the disc is to the axis, the slower the speed for a given rate of rotation. Even then, it's not displacing air, because it's already displaced by other portions of the disc, so the only interaction with the atmosphere, if there is one, would be skin friction.

Rotating habitats in orbit can be constructed with net zero angular momentum, making them just as easy to stop. No advantage to Mars.

How so, counter-rotation? You do that and you're increasing stresses and introducing bearings and more technical issues with load management and systems integration and propulsion, if your hab is mobile, as your comments about vacations suggest.

You could likely pressurize work areas in orbit to degrees similar to those outside Mars habitats without too much trouble, and orbital habitats also have access to arbitrarily low gravity. The repair/maintenance advantage is on the side of orbital habitats.

Do you mean to pressurize the hard vacuum of space? (and to the terraformed STP) And the hab's access to low gravity isn't arbitrary, it's limited by spin, radius, deck placement, deck plating curvature and the Coriolis effect. And I think you underestimate the utility of a constant gravity field on worker precision, accuracy, speed and safety.

Lack of a gravity field means orbital habitats would have cheaper shielding, not Mars surface ones.

How do you arrive at that conclusion? First, you have to create it. Second, you need to get it there. Third, you need to put it in place. Fourth, you need to keep it there during maneuvers (assuming a mobile hab, remember).

Martian solar power is vastly more complex...sun tracking, nighttime periods, dust and weather, all the various issues I've already raised. Nuclear power...only minor differences, the atmosphere being too thin to be a really useful heat sink. Both will need large radiators. Radiators on Mars won't be able to avoid the sun and Mars itself.

I prefer nuclear, or geothermal if available (I use geo-for every planet/moon, btw). But as for solar, it's not much different than earth, except for the difference in insolation. Nighttime's not a problem if day coincides with peak load. The current dust of mars may be worse than earth dust, but we're planning to terraform it so the STP may change the physical characteristics of that dust. As for radiators, umbrellas... although I hope to use a lot of it for residential and industrial process heat. Alternately, geothermal heat-sinking might be a possible, but there may be cooling towers with coolants or we could always toss water ice and dry ice on the radiators. Of course, radiator performance will vary depending on the atmosphere's STP during/after terraforming.

I really doubt that. You can't make it Earthlike enough for that to be anything but a tremendous waste of natural resources in the long run, while also being horribly expensive in the short term. In comparison, an operation to freeze out CO2 provides a useful raw material while working to reduce the transport costs involved in the export of CO2, water, etc.

Got evidence that there's not enough potential for a thicker atmosphere or that we can't import/produce more gasses?

Terraforming: a huge investment required to accomplish anything with negative payoff due to the increases in atmospheric hazards and loss of concentrated deposits of volatiles.

I think you overestimate the costs of terraforming Mars and underestimate the utility and desire of the result. Atmospheric hazards for what? Do you think that terraforming Mars means razing Olympus Mons? Use that for your spaceport. As for volatiles, you have lots of better sources with easy delta-v requirements.

Lunaforming: likely immediate profit, or at least very low cost compared to the massive industry needed for terraforming (a simple shade fence near a pole could keep a lot of CO2 frozen), leading to future reduced costs.

And yeah, there are other airless bodies in the solar system...and lunaforming would let you use technologies developed for them on Mars, while gaining access to the things Mars has that they generally will lack...minerals concentrated and processed by ancient liquid water, for example.

I think you underestimate the cost to kill Mars and over-estimate the return on investment for volatile mining.

[Ara Pacis]

Nomads on Earth have been combining both for millenia. With a mobile space habitat, you can travel and bring your whole neighborhood with you!

Sure, but I'm not one of them. If I get wanderlust, I go on a trip, then come back home.

[Noclevername]

Sure, but I'm not one of them. If I get wanderlust, I go on a trip, then come back home.

Fine, you take the planets, and we'll keep the rest of the universe. Remember, Pluto is one of ours now!

[cjameshuff]

Not necessarily. Lots of people commute to jobs for a season and then go back home. Not all migrant workers are lettuce pickers, some work on oil rigs, some drive on ice road, some fish the Bering Sea some play poker in the torpedo room when no one's around because their bored and hope they'll stay that way.

...
And how will migrant workers do that commute without access to transportation? You're making my point for me.

I know Teddy Roosevelt was looked at strangely when he set up the National Park system for that sorta thing. And Edmund Hillary, what a weirdo.

You're making my point for me again. People don't have to live in national parks to benefit from them.

Well, we deal with it on Earth, so maybe we can deal with it on Mars.

We don't need to.

A lot of people like to visit the Grand Canyon, Niagara Falls, Pikes Peak, Yellowstone, glaciers, etc --people are strange, eh? Some people even build houses with windows so that they can look out their window just to see certain rocks. Go figure. Oh, but microgravity/spinning-hab greenhouses and parks will be distinguishable from planet-side gardens, parks and greenhouses because of the Coriolis effect and radial configuration.

People can still visit. Very few people decide to live in central Antarctica just so they can look at snow and rocks.

Oh, if you do some physics experiments you can tell you're rotating faster than once per 20-something hours. How horrible...ridiculous!

I think you're over-estimating the loads on a planetary habitat that's spinning and underestimating the possible loads on rotating habs in space. You don't even need bearings in space if everything rotates as one item, but then you'll have difficulty with alignment for solar panels, communications antenna/dishes, telescopes, and spacecraft that bring supplies and passengers will have to perform ballet.

You have no argument here. Bearings that support the entire weight of the habitat will be heavier loaded than ones that support small imbalances while the ballast system works to compensate, it is absurd to suggest the latter will come anywhere close to the former...and orbital habitats don't even necessarily need bearings. We already have many solutions to antenna and array pointing and docking with spacecraft is not a problem.

Are you referring to what Noclevername mentioned earlier? You don't need a bullet train in order to go 43 MPH. That's assuming people can deal with 3 RPMs. If they prefer 2 RPMs then the speed will need to increase to 64 MPH, and the rotating portion of the habitat would increase in size too. Of course, only the outer-most portion of the spinning disc would move at that speed. The closer the surface of the disc is to the axis, the slower the speed for a given rate of rotation. Even then, it's not displacing air, because it's already displaced by other portions of the disc, so the only interaction with the atmosphere, if there is one, would be skin friction.

For comfort you need a large radius of rotation. Again, you have no argument here...this is simply not practical to do in a substantial atmosphere.

How so, counter-rotation? You do that and you're increasing stresses and introducing bearings and more technical issues with load management and systems integration and propulsion, if your hab is mobile, as your comments about vacations suggest.

None of these issues are even particularly difficult to solve in comparison to the ones involved in putting a rotating habitat on a planetary surface. And no, I am not suggesting that the habitats would be particularly mobile.

Do you mean to pressurize the hard vacuum of space? (and to the terraformed STP) And the hab's access to low gravity isn't arbitrary, it's limited by spin, radius, deck placement, deck plating curvature and the Coriolis effect. And I think you underestimate the utility of a constant gravity field on worker precision, accuracy, speed and safety.

The same way as always...enclose a portion of it! And the hab's access to low gravity is because of its use of spin...you can reduce spin to achieve microgravity environments all the way out to the rim. You have nothing to support your assertion that the variation in gravity is such an overwhelming disadvantage in comparison to all the many advantages.

How do you arrive at that conclusion? First, you have to create it. Second, you need to get it there. Third, you need to put it in place. Fourth, you need to keep it there during maneuvers (assuming a mobile hab, remember).

Large masses of material will be cheaper to move and support in microgravity. Mars gravity might be less than Earth's, but it still means you need structural support to keep your roof from falling in you don't need in orbit.

I prefer nuclear, or geothermal if available (I use geo-for every planet/moon, btw). But as for solar, it's not much different than earth, except for the difference in insolation. Nighttime's not a problem if day coincides with peak load. The current dust of mars may be worse than earth dust, but we're planning to terraform it so the STP may change the physical characteristics of that dust. As for radiators, umbrellas... although I hope to use a lot of it for residential and industrial process heat. Alternately, geothermal heat-sinking might be a possible, but there may be cooling towers with coolants or we could always toss water ice and dry ice on the radiators. Of course, radiator performance will vary depending on the atmosphere's STP during/after terraforming.

And solar's more or less impractical on Earth's surface, too. Nighttime's a problem regardless of where peak load is, especially on a habitat where power is needed for life support. Dust is worse than no dust. And where are you going to get those chunks of water ice and dry ice? You've vaporized them all to bring the pressure up!

Got evidence that there's not enough potential for a thicker atmosphere or that we can't import/produce more gasses?

Look at Mars. Estimates of the achievable pressure are on the order of 0.3 bar, using plain CO2. Lower if you try to convert any to oxygen. It gets half the sunlight Earth does, and loses heat rapidly. It has plentiful water in terms of industrial resources, but not enough to make the planet more than a parched desert. It will never be a nice place to take a stroll outside, the best you can hope for is "survivable if you have an oxygen mask and access to an emergency shelter".

I think you overestimate the costs of terraforming Mars and underestimate the utility and desire of the result. Atmospheric hazards for what? Do you think that terraforming Mars means razing Olympus Mons? Use that for your spaceport. As for volatiles, you have lots of better sources with easy delta-v requirements.

I think you underestimate the cost to kill Mars and over-estimate the return on investment for volatile mining.

You haven't provided anything to convince me I'm wrong. Volatiles are used for everything, we're talking the main raw material for propellants, polymers, pharmaceuticals, food, air, etc. Mining them will be an enormous business, and Mars is one of the best sources in that part of the solar system. Piling them up in a shallow gravity well to pressurize the surface is simply an absurd waste of natural resources that could be put to vastly better use. And if anything, I'm underestimating the cost of terraforming...not even considering the constant maintenance required to keep Mars terraformed, or of the alternate uses for asteroids used in impact heating and such.

As for war, I'm confident that the only people who'll continue to want a terraformed Mars are those who sit back on Earth and have nothing to do with space, and they'll never get anything moving because of lack of real interest and the overwhelming cost of making even minor progress. Those who live in space will see the possibilities of what they could do instead.

[Noclevername]

As for war, I'm confident that the only people who'll continue to want a terraformed Mars are those who sit back on Earth and have nothing to do with space, and they'll never get anything moving because of lack of real interest and the overwhelming cost of making even minor progress. Those who live in space will see the possibilities of what they could do instead.

Have you seen how dedicated some of the terraformers are? And how anxious to be on Mars and started already? I think you're fooling yourself.

[Hop_David]

Terra form Mars as much as possible,

Terraforming Mars is a pipe dream. Much of the enthusiasm for Mars comes from delusional day dreams.

[Noclevername]

Terraforming Mars is a pipe dream. Much of the enthusiasm for Mars comes from delusional day dreams.

Well, that's certainly a convincing argument.

You assume this why?

[Hop_David]

Well, that's certainly a convincing argument.

You assume this why?

Here is one scheme for terraforming Mars. McKay suggests nudging a large ammonia rich asteroid to impact Mars. It's his hope that the warmth and volatiles from a few such impacts would vaporize the CO2 at the poles and start a runaway greenhouse effect at Mars.

To nudge this body, he suggests sending out "a quartet of 5000 MW nuclear thermal rocket engines". That 20 giga watts, about the same as 6 Palo Verde Nuclear Power Plants. And he wants to send these NTRs to a body 12 AUs out in the solar system. He proposes using the asteroids volatiles as reaction mass so a mining and transportation infrastructure would be need to built on the asteroid to deliver reaction mass to the NTR's rocket chamber.

This particular scheme is 3 or 4 orders of magnitude more ambitious than landing humans on Mars. And landing humans on Mars is several orders of magnitude more ambitious than Mars sample return. You may have noticed a joint ESA NASA Mars sample return proposal recently fell through due to lack of funding.

Sorry, but Kim Stanley Robinson's science fiction is only marginally more plausible than Star Trek.

Naysayers like Stross or Murphy will portray space zealots as long on religious fervor and short on math and engineering skill. Sadly there is some basis for the Space Cadet stereotype. As is demonstrated by the number of people that believe it's plausible to terraform Mars.

[Noclevername]

That's hardly the only-- or most plausible-- terraforming proposal. And you might note that, aside from a few, no one is actually suggesting starting terraforming now. It's something for when we have a matured space-based industrial society, with the resources available for such megascale projects, and more advanced technology and a far greater knowledge of Mars and its potential resources. At least a couple of centuries, if not more.

Nudging comets and asteroids into new orbits is something we need to practice for our own safety anyway.

[Ara Pacis]

...
And how will migrant workers do that commute without access to transportation? You're making my point for me.

Why do you keep insisting that there can't be a space transit infrastructure or even just the ocassional spaceship without scads of people actually making their home in space? Most people who drive cars to work or on vacation still have a home to go back to. *looking at later responses* And you wonder why I think you're referring to mobile habitats when you keep conflating space transit with living in space?

You're making my point for me again. People don't have to live in national parks to benefit from them.

What made you think that living in a park was my point? My point was that you want to destroy it so people won't be able to visit it. And I suppose you're right that those who would want to live there can't do that either after you obliterate the natural beauty.

We don't need to.

And how do you propose to get those precious volatiles and other mined materials off-planet, Jedi Force levitation? Unless you have rocket craft hovering above the surface of Mars, high enough to avoid any quake effects, your structures going to be at risk of seismic motion.

People can still visit. Very few people decide to live in central Antarctica just so they can look at snow and rocks.

The plan is to change it into something other than just snow and rocks. Still, a lot of people do like to look at snow and rocks. You may be surprised at the number of people who have windows that look upon the snow-capped peaks of their local mountains or have pictures/paintings on their walls depicting such scenes.

Oh, if you do some physics experiments you can tell you're rotating faster than once per 20-something hours. How horrible...ridiculous!

If your habitat's radius is that large you'll have plenty of other problems with materials stresses, like tidal effects. Perhaps you can build it that big, but why would you want to? And if you want to talk about ridiculous, you think my habitat that fits inside a football stadium is more ambitious than your habitat that's roughly twice the size of the sun? Really?

You have no argument here. Bearings that support the entire weight of the habitat will be heavier loaded than ones that support small imbalances while the ballast system works to compensate, it is absurd to suggest the latter will come anywhere close to the former...and orbital habitats don't even necessarily need bearings. We already have many solutions to antenna and array pointing and docking with spacecraft is not a problem.

Now that I realize the scale of your habitat, it is kinda silly to argue similarities when there are seven or more orders of magnitude difference in size. Rest assured, however, that the mass borne by bearings in my design is piddlin' compared to the mass of yours. Antennae may not be a problem, but a craft trying to dock will have a very hard time when the rim is moving at over 110 KPS.

For comfort you need a large radius of rotation. Again, you have no argument here...this is simply not practical to do in a substantial atmosphere.

Not that large a radius. Studies suggest 3 RMP is the max, which only needs a 62m radius for earth comparable gravity on Mars. And even at that radius, it's less than a 3% difference in acceleration between the top of the head and the sole of the feet, less if you measure to the vestibular system organs.

None of these issues are even particularly difficult to solve in comparison to the ones involved in putting a rotating habitat on a planetary surface. And no, I am not suggesting that the habitats would be particularly mobile.

Show us how you'll have "net zero angular momentum" in a hab like you mentioned, that's twice the size of the sun. And yeah, I wouldn't expect it to be that mobile, but you did mention that the residents would be able to visit other destinations compared to Marsiens, but if you're just suggesting they'll take a transit vehicle, then Marsies can do that too. And when I wrote "We're talking about living, not traversing," you wrote that the two are inseparable. Are you back-tracking now?

The same way as always...enclose a portion of it! And the hab's access to low gravity is because of its use of spin...you can reduce spin to achieve microgravity environments all the way out to the rim. You have nothing to support your assertion that the variation in gravity is such an overwhelming disadvantage in comparison to all the many advantages.

Enclosing a rotating hab inside an air envelope... I've suggested that before (cycler thread), and even suggested it above for use on Mars and you sounded incredulous because of aerodynamics which you failed or refused to explain. How do you propose to make it more credulous to enclose the a double-sun-wide hab to support for your argument? How do you propose to change the rotation of it safely and with "net zero angular momentum"?

Large masses of material will be cheaper to move and support in microgravity. Mars gravity might be less than Earth's, but it still means you need structural support to keep your roof from falling in you don't need in orbit.

First of all, it's silly to compare the movement of a ~30 thousand tons for my design's shield with the hundreds of gigatons needed in yours. However, if we look at it per unit mass, what makes you think yours is cheaper? For mine, you just need some basic earth moving equipment to elevate stuff a few tens of meters to dump it into baffles. For you, you have to go get it from an asteroid, moon or planet, shape it somehow, use propellant to get it to where the habitat is, and then put it in place and somehow secure it. Prove that it's cheaper to move mass in microgravity. At least on Mars you have the entire mass of the planet to brake against instead of needing retro-thrust, and gravity is actually helpful because it holds stuff in buckets on the equipment and shield baffles.

And solar's more or less impractical on Earth's surface, too. Nighttime's a problem regardless of where peak load is, especially on a habitat where power is needed for life support. Dust is worse than no dust. And where are you going to get those chunks of water ice and dry ice? You've vaporized them all to bring the pressure up!

Batteries of some sort can be used at night. And ice is available if we haven't finished creating the atmosphere yet. If we have created an atmosphere, then the atmosphere can cool the radiators via convection.

Look at Mars. Estimates of the achievable pressure are on the order of 0.3 bar, using plain CO2. Lower if you try to convert any to oxygen. It gets half the sunlight Earth does, and loses heat rapidly. It has plentiful water in terms of industrial resources, but not enough to make the planet more than a parched desert. It will never be a nice place to take a stroll outside, the best you can hope for is "survivable if you have an oxygen mask and access to an emergency shelter".

And how is this more dangerous than a space habitat in vacuum? And as I also mentioned, we can import gases and may be able to mine more ore synthesize others. And we still don't know the potential pressure attainable, so it may be higher. The variation in topography means we can achieve more useful results in some areas while we can paraterraform other areas.

You haven't provided anything to convince me I'm wrong. Volatiles are used for everything, we're talking the main raw material for propellants, polymers, pharmaceuticals, food, air, etc. Mining them will be an enormous business, and Mars is one of the best sources in that part of the solar system. Piling them up in a shallow gravity well to pressurize the surface is simply an absurd waste of natural resources that could be put to vastly better use. And if anything, I'm underestimating the cost of terraforming...not even considering the constant maintenance required to keep Mars terraformed, or of the alternate uses for asteroids used in impact heating and such.

I'm not sure it's possible to convince you that you're wrong, especially when your counter-arguments are vastly out of proportion and lack any explanatory detail or mathematical quantification or scientific qualification. Mars may be a source for materials for your hab, but it's in a gravity well. Why not get them from the Galilean moons or Titan or Ceres or the atmosphere of Venus? Do you think there will be such a shortage of asteroids and other objects for your projects such that using them to gasify Mars becomes prohibitive? Srsly? I know that a hundred gigatons is a lot, but it's still only a small fraction of the mass the larger asteroids. How expensive do you think it will be to Terraform Mars? How cheap do you think it will be to create one or more rotating double-sun-wide ring-worlds in space?

As for war, I'm confident that the only people who'll continue to want a terraformed Mars are those who sit back on Earth and have nothing to do with space, and they'll never get anything moving because of lack of real interest and the overwhelming cost of making even minor progress. Those who live in space will see the possibilities of what they could do instead.

War?

So, am I to assume that you've ceded the argument on all the points I made that you didn't respond do?

[Ara Pacis]

Here is one scheme for terraforming Mars. McKay suggests nudging a large ammonia rich asteroid to impact Mars. It's his hope that the warmth and volatiles from a few such impacts would vaporize the CO2 at the poles and start a runaway greenhouse effect at Mars.

To nudge this body, he suggests sending out "a quartet of 5000 MW nuclear thermal rocket engines". That 20 giga watts, about the same as 6 Palo Verde Nuclear Power Plants. And he wants to send these NTRs to a body 12 AUs out in the solar system. He proposes using the asteroids volatiles as reaction mass so a mining and transportation infrastructure would be need to built on the asteroid to deliver reaction mass to the NTR's rocket chamber.

This particular scheme is 3 or 4 orders of magnitude more ambitious than landing humans on Mars. And landing humans on Mars is several orders of magnitude more ambitious than Mars sample return. You may have noticed a joint ESA NASA Mars sample return proposal recently fell through due to lack of funding.

Sorry, but Kim Stanley Robinson's science fiction is only marginally more plausible than Star Trek.

Naysayers like Stross or Murphy will portray space zealots as long on religious fervor and short on math and engineering skill. Sadly there is some basis for the Space Cadet stereotype. As is demonstrated by the number of people that believe it's plausible to terraform Mars.

There's more than one way to skin a cat. Instead of installing an outboard motor on a moon, asteroid or TNO, we could just Chunk-n-Chuck it (I ought to trademark that name) using a mass driver and some aluminum foil to insulate against the sun. That's for volatiles. A solar reflector could be done with aluminum foil, using a single rolling mill would take ~18 years to make enough for the commonly quoted reflective area, quicker if you use more than one machine. I assume we'll have a lot of aluminum (foil, sheet metal, extruded beams) being used in space and sourced from the moons and elsewhere.

[cjameshuff]

What made you think that living in a park was my point? My point was that you want to destroy it so people won't be able to visit it. And I suppose you're right that those who would want to live there can't do that either after you obliterate the natural beauty.

Obliterate it? Mars with a thinner atmosphere is little unlike Mars with an atmosphere, just with a darker sky. Terraforming would make a vastly greater and more unnatural change.

And how do you propose to get those precious volatiles and other mined materials off-planet, Jedi Force levitation? Unless you have rocket craft hovering above the surface of Mars, high enough to avoid any quake effects, your structures going to be at risk of seismic motion.

Some structures. I'm arguing that terraforming is wasteful and that orbit is a better place for people to live than the Martian surface, not that surface structures are impossible. Please stop putting up straw man arguments.

If your habitat's radius is that large you'll have plenty of other problems with materials stresses, like tidal effects. Perhaps you can build it that big, but why would you want to? And if you want to talk about ridiculous, you think my habitat that fits inside a football stadium is more ambitious than your habitat that's roughly twice the size of the sun? Really?

...twice the size of the sun? What are you talking about?

Now that I realize the scale of your habitat, it is kinda silly to argue similarities when there are seven or more orders of magnitude difference in size. Rest assured, however, that the mass borne by bearings in my design is piddlin' compared to the mass of yours. Antennae may not be a problem, but a craft trying to dock will have a very hard time when the rim is moving at over 110 KPS.

Again, what are you talking about? What have I said to indicate a rim velocity almost 4 times the orbital velocity of Earth?

Not that large a radius. Studies suggest 3 RMP is the max, which only needs a 62m radius for earth comparable gravity on Mars. And even at that radius, it's less than a 3% difference in acceleration between the top of the head and the sole of the feet, less if you measure to the vestibular system organs.

Studies indicate most people can adapt to 3 RPM. For comfort, accommodation of more sensitive individuals, a flatter apparent gravity field, larger and flatter floor areas, etc, a larger radius would still be preferable.

Show us how you'll have "net zero angular momentum" in a hab like you mentioned, that's twice the size of the sun. And yeah, I wouldn't expect it to be that mobile, but you did mention that the residents would be able to visit other destinations compared to Marsiens, but if you're just suggesting they'll take a transit vehicle, then Marsies can do that too. And when I wrote "We're talking about living, not traversing," you wrote that the two are inseparable. Are you back-tracking now?

I have no idea where you got the "twice the size of the sun" thing. Zero net angular momentum is quite trivial, two counterrotating sections.

Enclosing a rotating hab inside an air envelope... I've suggested that before (cycler thread), and even suggested it above for use on Mars and you sounded incredulous because of aerodynamics which you failed or refused to explain. How do you propose to make it more credulous to enclose the a double-sun-wide hab to support for your argument? How do you propose to change the rotation of it safely and with "net zero angular momentum"?

No. Enclosing a work area. The issues with a pressurized enclosure have been fully explained...drag losses! And the double-sun-wide habitat is your own absurd creation!

First of all, it's silly to compare the movement of a ~30 thousand tons for my design's shield with the hundreds of gigatons needed in yours. However, if we look at it per unit mass, what makes you think yours is cheaper? For mine, you just need some basic earth moving equipment to elevate stuff a few tens of meters to dump it into baffles. For you, you have to go get it from an asteroid, moon or planet, shape it somehow, use propellant to get it to where the habitat is, and then put it in place and somehow secure it. Prove that it's cheaper to move mass in microgravity. At least on Mars you have the entire mass of the planet to brake against instead of needing retro-thrust, and gravity is actually helpful because it holds stuff in buckets on the equipment and shield baffles.

Bags of slag and other waste, tied to a frame which need only hold them against tidal forces, disturbances from workers, etc. You don't need to construct a heavy duty roof and then layer rock and dirt over it. And you don't need gigatons just because you're in orbit.

Batteries of some sort can be used at night. And ice is available if we haven't finished creating the atmosphere yet. If we have created an atmosphere, then the atmosphere can cool the radiators via convection.

"Batteries of some kind"...which are unnecessary off-planet.

And how is this more dangerous than a space habitat in vacuum? And as I also mentioned, we can import gases and may be able to mine more ore synthesize others. And we still don't know the potential pressure attainable, so it may be higher. The variation in topography means we can achieve more useful results in some areas while we can paraterraform other areas.

My argument is not that terraforming is "more dangerous"! And no, you can not feasibly import enough gases to make a difference. Do you have any idea how much mass you'd need to move? Or how incredibly wasteful spreading it over a small cold desert world for use as dead weight to build up surface pressure would be?

So, am I to assume that you've ceded the argument on all the points I made that you didn't respond do?

No. Many of them simply weren't worth addressing...I'm not going to exhaustively address every minuscule little detail you can tack on to a fundamentally flawed argument and every straw man or red herring you can come up with.

[Blackhole]

I believe evolution of the human race on Mars for thousands of years would include a natural long-term adaptation to the new environment. We would start off living in man-made structures mechanically engineered to create an Earth-like environment on the surface of Mars. With Terra-forming and improved space suits, in a couple thousand years we would be able to survive outside on Mars for an hour or so a day, and then 12 hours a day... and then for an entire Mars day. During this transition the human skin, lungs, eyes, ears, mouth, brain, hair might adapt and evolve to suit the surface conditions of the red planet.

More to the OP's question, I do believe there is the possibility of biology taking quantum leaps in the next few centuries which may enable humans to biologically engineer our bodies to become smarter, faster, stronger and to adapt to different environments. With the further development of stem-cell research, as well as perhaps micro chips implanted to make the brain bigger, it's hard to put a lid on what humans will be able to accomplish.

Despite all of our problems, I remain a strong believer in the human race.

[Hop_David]

There's more than one way to skin a cat. Instead of installing an outboard motor on a moon, asteroid or TNO, we could just Chunk-n-Chuck it (I ought to trademark that name) using a mass driver and some aluminum foil to insulate against the sun. That's for volatiles. A solar reflector could be done with aluminum foil, using a single rolling mill would take ~18 years to make enough for the commonly quoted reflective area, quicker if you use more than one machine. I assume we'll have a lot of aluminum (foil, sheet metal, extruded beams) being used in space and sourced from the moons and elsewhere.

Volatiles and aluminum for the moons and elsewhere? So for your terraforming project you're assuming we already have extensive infrastructure on the moon and asteroids?

[Noclevername]

Volatiles and aluminum for the moons and elsewhere? So for your terraforming project you're assuming we already have extensive infrastructure on the moon and asteroids?

You've got it backwards-- we have to have the infrastructure before we start terraforming, or doing any other major industrial projects in space (like building sufficiently large habitats for permanent colony* orbital settlement). It's a necessary prerequisite.

* Sorry, I forgot that we don't "want" to use that word that's been used for proposed lifetime space settlements since before I was born.

[Hop_David]

You've got it backwards-- we have to have the infrastructure before we start terraforming, or doing any other major industrial projects in space

Of course. I was trying to get Ara Pacis to admit as much. I certainly wasn't saying we could terraform without infrastructure.

So lets assume extensive mining and manufacturing infrastructure on asteroids.

Mined asteroidal volatiles, aluminum etc. would be immensely useful on the asteroids. Better to use these resources for the asteroid based civilization than sinking them into a Martian terraforming money pit that may or may not yield earthlike real estate millenia from now.

[Noclevername]

Of course. I was trying to get Ara Pacis to admit as much. I certainly wasn't saying we could terraform without infrastructure.

So lets assume extensive mining and manufacturing infrastructure on asteroids.

Mined asteroidal volatiles, aluminum etc. would be immensely useful on the asteroids. Better to use these resources for the asteroid based civilization than sinking them into a Martian terraforming money pit that may or may not yield earthlike real estate millenia from now.

Assuming we don't just use robots to mine asteroids. There might be no "Belters".

And if some of those mines and factories are owned by Martian settlers, they might disagree with you about what's better. It's not all-or-nothing, the Solar system has enough resources for plenty of big projects.

[Hop_David]

Assuming we don't just use robots to mine asteroids. There might be no "Belters".

Assuming fully robotic asteroid mines, volatiles and other resources would still be immensely useful at the asteroids.

And given the ability to establish asteroid mines and factories, building asteroidal habs would also be doable. Humans plus machines are far more able than machines alone, so there would be an incentive to build these habs.

And if some of those mines and factories are owned by Martian settlers, they might disagree with you about what's better.

How has this immensely wealthy Martian civilization come about? What are the martian exports that have fueled this civilization's growth?

[Noclevername]

Assuming fully robotic asteroid mines, volatiles and other resources would still be immensely useful at the asteroids.

They would be immensely useful everywhere in the Solar System. That's what the mines would be for.

And given the ability to establish mines and factories, building asteroidal habs would also be doable. Humans plus machines are far more able than machines alone, so there would be an incentive to build these habs.

That would be an incentive for establishing work stations, not colonization.

How has this immensely wealthy Martian civilization come about? What are the martian exports that have fueled this civilization's growth?

Miners. They put in their time at the asteroid mines running robots, then some settled down on Ares Firma.

[Hop_David]

Miners. They put in their time at the asteroid mines running robots, then some settled down on Ares Firma.

Which gets us back to square one -- tin cans on Mars vs tin cans on asteroids. Why would a tin can at the bottom of a deep gravity well be more desirable than an orbital tin can? Because it's so much harder to come and go?

[Noclevername]

Which gets us back to square one -- tin cans on Mars vs tin cans on asteroids. Why would a tin can at the bottom of a deep gravity well be more desirable than an orbital tin can? Because it's so much harder to come and go?

I don't know, I'm a Spacer at heart. But I've met people who really, really want this.

There are many of them.

And they have a plan.

(Sorry, couldn't resist)

[Noclevername]

It could be that some want terraforming because they want to do away with tin cans. (And don't ask why they don't stay on Earth, there's already several threads for that.)

As to how they might do it, bootstrapping would be my bet. Time-consuming, but it doesn't require a lot of outside help once it's started.