B Survival on Mars: Radiation & Temperature Challenges

[Pete Cortez]

You can't expand to empty space, just to places with enough building material

Or you can move building material to empty space, which is precisely what you'll want to do if you want to assemble--say--O'Neill cylinders at Earth-Lunar libration.

Let's face it, you can't "just" expand into any place in the solar system. Everywhere off Earth is extremely hostile in comparison.

travelling between asteroids (and properly spin up colonies) requires a good amount of delta-V even if one don't have to leave a gravity well.

More often than not less than getting off Earth in the first place, and considerably so for several NEAs. And also considerably less than the delta-v budget needed to get to Mars' surface. And even considered more exotic, optimal paths to specific targets.

3. I also think that building bases for constant living on Moon will be a very good practice and convincing that we can do that (while evacuate people if we fail), at least.

The Moon's proximity to Earth is about her only saving grace, but it's a very big mark in her favor. Until we can shepherd comets and asteroids closer to Earth and/or stand up a reliable transportation network to NEAs and comets, the Moon is the most advantageous place to make gas and refine building materials within our reach. But I can definitely imagine a future where the Moon, once a booming nexus of early space settlement activity, ends up being littered with ghost towns as easier to access resources become available.

 

[GTOM]

NEA mining is quite reasonable, but building permanent, self sustaining settlements there is a different thing.
I don't deny that mining and trading with Earth are powerful factors, but living on planets is far better i think. If we can construct an artificial biosphere in space, i think we can solve landing on another planet also.
Many challenges are the same in the two case, however, on a planet, you won't run out of building material, people can see a horizont, a sky, leave the domes at least for a short time, transport between cities is easy (no need for rockets), you don't need to spin up everything, protection from radiation and micrometeors is easier. Probably in the future, leaving a planet will be also easier, in weaker gravity we could construct a space elevator.

 

[Pete Cortez]

NEA mining is quite reasonable, but building permanent, self sustaining settlements there is a different thing.

Building permanent, self-sustaining settlements anywhere off Earth is a different thing. I'd argue it's still easier to build them in freefall than while fighting surface gravity.

I don't deny that mining and trading with Earth are powerful factors, but living on planets is far better i think. If we can construct an artificial biosphere in space, i think we can solve landing on another planet also.

It's not a matter of finding solutions so much as picking optimal ones out of our current basket. I'd argue it's cheaper to hollow out a rock in freefall and fill it with water and atmosphere sourced from comets and the like than to set up a mining and transport operation for most of that material at Martian surface gravity. I also get the benefit of all sorts of raw material left over from primary construction just floating around outside waiting to be used.

Many challenges are the same in the two case, however, on a planet, you won't run out of building material

You won't run out of building material in space, either.

people can see a horizont, a sky...

I hope we're not making decisions to settle places based on whether or not there's a horizon. As for a sky, this doesn't work?

leave the domes at least for a short time

And this is different from a space habitat how? Not only could you leave the habitat, you get to enjoy freefall as well.

transport between cities is easy (no need for rockets)

Setting aside you can build multiple cities in a single asteroid, you can also connect multiple asteroids with cables. Or you can use tethers to fling material around. Or they simply might be close enough that you can get around in a reasonable amount of time on electric rocket propulsion. But most importantly, you'll be able to travel between destinations on very low energy paths, with delta-vs comparable to motor vehicle and air travel (within the same Lagrange neighborhood at least).

...you don't need to spin up everything

This is, to a first order approximation, a one time cost. And not necessarily a substantial one. In fact, you could conceivably use the extraction operation on an asteroid to provide spin by flinging byproduct into space. With good project and waste management, you can work it out so that all your heavy lifting work is done while rotation is close to zero.

protection from radiation and micrometeors is easier.

It's also easy by having a couple of meters of rock around you. Natural light can be reflected in through an opening on the end facing safely away from the sun.

Probably in the future, leaving a planet will be also easier, in weaker gravity we could construct a space elevator.

Remember, the same technologies you can apply to making it easier to lift off a planet can be used to make freefrall travel easier as well. A space elevator is a special case of a tether.

 

[Drakkith]

Building permanent, self-sustaining settlements anywhere off Earth is a different thing. I'd argue it's still easier to build them in freefall than while fighting surface gravity.

I don't think I agree. Both environments have different engineering requirements, and I don't think one is inherently easier than the other.

It's not a matter of finding solutions so much as picking optimal ones out of our current basket. I'd argue it's cheaper to hollow out a rock in freefall and fill it with water and atmosphere sourced from comets and the like than to set up a mining and transport operation for most of that material at Martian surface gravity. I also get the benefit of all sorts of raw material left over from primary construction just floating around outside waiting to be used.

I don't agree with this either. Comets have substantially different orbits than asteroids and I'd bet the fuel costs just getting to the comet and back would probably not make this worthwhile, and that's not even considering the cost of the operation to "mine" the comet.

And this is different from a space habitat how? Not only could you leave the habitat, you get to enjoy freefall as well.

Freefall is not something I'd consider to be enjoyable for most people. There's a reason why the zero-g training aircraft is nicknamed "vomit comet".

Setting aside you can build multiple cities in a single asteroid, you can also connect multiple asteroids with cables. Or you can use tethers to fling material around. Or they simply might be close enough that you can get around in a reasonable amount of time on electric rocket propulsion. But most importantly, you'll be able to travel between destinations on very low energy paths, with delta-vs comparable to motor vehicle and air travel (within the same Lagrange neighborhood at least).

You are not going to be able to connect multiple asteroids with cables. The average distance between asteroids is something like a few hundred thousand miles. Travel time between them would probably be a minimum of a few days, and that's with considerable fuel expended for acceleration and deceleration.

 

[Pete Cortez]

I don't think I agree. Both environments have different engineering requirements, and I don't think one is inherently easier than the other.

Energy-wise, there's a sharp distinction. Specifically where it concerns per pound, end-to-end transportation cost of materials. Even if we set aside the cost of dropping material and assume we build everything with material extracted from surface, you still have the energy expended overcoming friction. That concern is negligible in freefall transportation.

I don't agree with this either. Comets have substantially different orbits than asteroids and I'd bet the fuel costs just getting to the comet and back would probably not make this worthwhile, and that's not even considering the cost of the operation to "mine" the comet.

You'll want to capture them on close approach, and pick off the ones with low relative velocity. And assuming you don't want to use nukes to capture them, then pick a large enough one and start cracking hydrolox for propellant.

Freefall is not something I'd consider to be enjoyable for most people. There's a reason why the zero-g training aircraft is nicknamed "vomit comet".

There's a degree of acclimation, yes.

You are not going to be able to connect multiple asteroids with cables. The average distance between asteroids is something like a few hundred thousand miles. Travel time between them would probably be a minimum of a few days, and that's with considerable fuel expended for acceleration and deceleration.

I'm proposing connecting captured asteroids that have been parked in cislunar space. The average minimum distance is whatever traffic control says is safe. That's the beautiful thing about asteroids. They're mountains we can move.

 

[Drakkith]

Energy-wise, there's a sharp distinction. Specifically where it concerns per pound, end-to-end transportation cost of materials. Even if we set aside the cost of dropping material and assume we build everything with material extracted from surface, you still have the energy expended overcoming friction. That concern is negligible in freefall transportation.

Just because it may use less energy does not mean that it is easier. Working in zero-g and in a vacuum is much different than working on the surface of a planet, and comes with its own set of difficulties and engineering challenges.

You'll want to capture them on close approach, and pick off the ones with low relative velocity. And assuming you don't want to use nukes to capture them, then pick a large enough one and start cracking hydrolox for propellant.

I'm sorry but I feel like you're hand-waving the difficulties away.

There's a degree of acclimation, yes.

Which isn't always possible. Plus there's the fact that any environment is almost certainly going to be simulating gravity by rotating, so the acclimation may wear off. That being said, I can easily imagine some pretty creative "recreational facilities" being setup in a zero-g environment. Just look at the battle arena in Enders Game for an example. I don't think you can fully replace a planetary environment with a zero-g one, but I can imagine you can get pretty close and in some cases exceed what is possible in certain ways.

I'm proposing connecting captured asteroids that have been parked in cislunar space. The average minimum distance is whatever traffic control says is safe. That's the beautiful thing about asteroids. They're mountains we can move.

Ignoring all the costs and difficulties associated with moving these asteroids in the first place, I still don't agree that transportation is necessarily easier between asteroids than between cities on a planet. I will agree that in certain areas, perhaps like moving large quantities of material, it may be easier, but general transportation of people and goods, no. The reliability and simplicity of ground vehicles simply can't be beat. You don't need to spend years learning how to pilot a truck like you do a spacecraft . Besides, if anything goes wrong, you can just get out and push!

 

[Pete Cortez]

Just because it may use less energy does not mean that it is easier. Working in zero-g and in a vacuum is much different than working on the surface of a planet, and comes with its own set of difficulties and engineering challenges.

When it comes to the vacuum and Mars, we're talking about the difference 0 and 0.6 percent of Earth's mean sea level pressure. And working in space doesn't necessarily mean working in freefall conditions. If there's work that's best performed under acceleration, you spin it. But I imagine a good deal of work with very massive components would be actually easier to perform in freefall.

I'm sorry but I feel like you're hand-waving the difficulties away.

Not handwaving them away; any project off Earth is going to be considerably difficult compared to its terrestrial equivalent. I'm simply addressing the comparative difficulty of working in space vs working on an extra-terrestrial planet.

Which isn't always possible.

It's going to have to be. There's no way to transport people off this planet to other destinations without them spending some time in freefall.

Plus there's the fact that any environment is almost certainly going to be simulating gravity by rotating, so the acclimation may wear off.

It may, it may not. Symptoms at this transition point are not well known. Then again, symptoms we may encounter on an extraterrestrial planet aren't well known either.

That being said, I can easily imagine some pretty creative "recreational facilities" being setup in a zero-g environment. Just look at the battle arena in Enders Game for an example. I don't think you can fully replace a planetary environment with a zero-g one, but I can imagine you can get pretty close and in some cases exceed what is possible in certain ways.

I can imagine some pretty creative recreational activities in freefall, too. ;)

Ignoring all the costs and difficulties associated with moving these asteroids in the first place, I still don't agree that transportation is necessarily easier between asteroids than between cities on a planet.

Which is easier? Transporting over rough terrain? Paving highways? Or running cables?

I will agree that in certain areas, perhaps like moving large quantities of material, it may be easier, but general transportation of people and goods, no. The reliability and simplicity of ground vehicles simply can't be beat.

Ground transport isn't simple the vehicle. It's also roads.

You don't need to spend years learning how to pilot a truck like you do a spacecraft .

We spend years learning to pilot spacecraft because there are so few of them and they perform several, extremely different roles (launch, orbiter, reentry). And who says you even need a pilot for an inter-asteroid cable car?

Besides, if anything goes wrong, you can just get out and push!

That's probably not practical for more than a few miles, and even then most people would opt for a tow truck, hitch a ride or just walk. And it's not like you wouldn't be able to do the same in the interior of these space habitats. The question is for long distance travel--the realm that is also well served by ship, train and plane.

 

[Drakkith]

When it comes to the vacuum and Mars, we're talking about the difference 0 and 0.6 percent of Earth's mean sea level pressure. And working in space doesn't necessarily mean working in freefall conditions. If there's work that's best performed under acceleration, you spin it. But I imagine a good deal of work with very massive components would be actually easier to perform in freefall.

I agree that certain things are easier in freefall, but I don't agree that it's inherently better than non-freefall. And I thought we were talking about building a settlement, in which case you wouldn't be able to use acceleration to help you build things since there's no settlement there to spin.

Not handwaving them away; any project off Earth is going to be considerably difficult compared to its terrestrial equivalent. I'm simply addressing the comparative difficulty of working in space vs working on an extra-terrestrial planet.

No, you're skipping over the cost and difficulties of a huge portion of the project. Think about what you're saying. You want to start a mining operation on a comet and then take everything you mine to fill a hollowed out asteroid. If you want to use Mars as an example, I can find plenty of O2 and water on Mars without needing to ever get into a rocket, completely negating any need to ship either of those to the colony.

It's going to have to be. There's no way to transport people off this planet to other destinations without them spending some time in freefall.

I agree that there's no way to avoid it, but that doesn't mean that everyone is going to be able to be acclimated to zero-g. Not everyone can ride in a car without getting motion sickness despite years of acclimation and medication to help. Regardless, I don't feel like arguing what people may or may not enjoy.

Which is easier? Transporting over rough terrain? Paving highways? Or running cables?

I don't see how it gets much easier than throwing your cargo in the back of a truck and driving down the road to the next city.

We spend years learning to pilot spacecraft because there are so few of them and they perform several, extremely different roles (launch, orbiter, reentry). And who says you even need a pilot for an inter-asteroid cable car?

We've had aircraft for over a century and people are still required to go through years of training before being handed a license. I highly doubt spacecraft are somehow going to require significantly less training, especially when just landing/docking is just as dangerous as aircraft landings are.

 

[Drakkith]

When it comes to the vacuum and Mars, we're talking about the difference 0 and 0.6 percent of Earth's mean sea level pressure. And working in space doesn't necessarily mean working in freefall conditions. If there's work that's best performed under acceleration, you spin it. But I imagine a good deal of work with very massive components would be actually easier to perform in freefall.

I agree that certain things are easier in freefall, but I don't agree that it's inherently better than non-freefall. And I thought we were talking about building a settlement, in which case you wouldn't be able to use acceleration to help you build things since there's no settlement there to spin.

Not handwaving them away; any project off Earth is going to be considerably difficult compared to its terrestrial equivalent. I'm simply addressing the comparative difficulty of working in space vs working on an extra-terrestrial planet.

No, you're skipping over the cost and difficulties of a huge portion of the project. Think about what you're saying. You want to start a mining operation on a comet and then take everything you mine to fill a hollowed out asteroid. If you want to use Mars as an example, I can find plenty of O2 and water on Mars without needing to ever get into a rocket, completely negating any need to ship either of those to the colony.

It's going to have to be. There's no way to transport people off this planet to other destinations without them spending some time in freefall.

I agree that there's no way to avoid it, but that doesn't mean that everyone is going to be able to be acclimated to zero-g. Not everyone can ride in a car without getting motion sickness despite years of acclimation and medication to help. Regardless, I don't feel like arguing what people may or may not enjoy.

Which is easier? Transporting over rough terrain? Paving highways? Or running cables?

I don't see how it gets much easier than throwing your cargo in the back of a truck and driving down the road to the next city. Basic roads are not very difficult to build.

We spend years learning to pilot spacecraft because there are so few of them and they perform several, extremely different roles (launch, orbiter, reentry). And who says you even need a pilot for an inter-asteroid cable car?

We've had aircraft for over a century and people are still required to go through years of training before being handed a license. I highly doubt spacecraft are somehow going to require significantly less training, especially when just landing/docking is just as dangerous as aircraft landings are.

 

[Pete Cortez]

I agree that certain things are easier in freefall, but I don't agree that it's inherently better than non-freefall. And I thought we were talking about building a settlement, in which case you wouldn't be able to use acceleration to help you build things since there's no settlement there to spin.

Go to any construction site and you'll see all sorts of temporary structures and scaffolds used to aid in the project. Any project--in space or on Mars--is going to require similar prep stations.

No, you're skipping over the cost and difficulties of a huge portion of the project.

Yes, in both environments.

Think about what you're saying. You want to start a mining operation on a comet and then take everything you mine to fill a hollowed out asteroid.

Yes, and I'd need to set up extraction operations on Mars to acquire the same minimum mass of volatiles and materials.

If you want to use Mars as an example, I can find plenty of O2 and water on Mars without needing to ever get into a rocket, completely negating any need to ship either of those to the colony.

Except of course the rocket to get bodies and equipment down on the surface in the first place.

I agree that there's no way to avoid it, but that doesn't mean that everyone is going to be able to be acclimated to zero-g. Not everyone can ride in a car without getting motion sickness despite years of acclimation and medication to help. Regardless, I don't feel like arguing what people may or may not enjoy.

I think we can both agree that there's not much fruit in comparing vistas of completely alien environments at this point.

I don't see how it gets much easier than throwing your cargo in the back of a truck and driving down the road to the next city. Basic roads are not very difficult to build.

Slinging cable is even easier to do. Hell, in space we're talking about a process not dissimilar from TPing the neighbor's tree on Halloween. In a vacuum. In freefall. With giant, hundreds of kilometers long spools of cable.

We've had aircraft for over a century and people are still required to go through years of training before being handed a license. I highly doubt spacecraft are somehow going to require significantly less training, especially when just landing/docking is just as dangerous as aircraft landings are.

We've had extraterrestrial rovers for over a century and people are still required to go through years of training before operating them. Let's face it, right now taking a dump in space involves training. We can't just say that erecting, maintaining and employing overland transportation on a planet with a third of Earth's gravity and 0.6 percent of its ground level atmospheric pressure is going to be a piece of cake. Also, when the pipeline for new operators is filled to the brim, it often takes longer to get certified than absolutely necessary. Commercial pilots, for example, are at the mercy of weather, finances, the availability of training aircraft, and demand for new aviators when filling in their logbook. Otherwise, indoc, classroom instruction and the 200-400 hours of flying time required to pick up all the certifications required to fly professionally could be completed in a matter of weeks.

 

[GTOM]

"I hope we're not making decisions to settle places based on whether or not there's a horizon. As for a sky, this doesn't work?"

If we talk about permanent settlements, whether people feeling comfortable or not, is not negligable.

You need a pretty big tin can to have something like the sky. Yes i can get out, in a big metallic space suit, and see the big nothing (ok, in the vicinity of Earth, not just that), have to stay connected with cables... On Mars, a lighter space activity suit (http://en.wikipedia.org/wiki/Space_activity_suit) and a car with own oxygen and hermetically closed doors is enough.

I think we got pretty accustomed with building high towers in Earth gravity, once we landed on Mars, we can forget rockets, and use regular land vehicles and cranes in order to further expand. I'm not sure but i guess the delta-V needed to spin up asteroids is also enough to land on Mars.
Construct roads, high-railways, build rovers that can go on rought terrain, yes it isn't that easy, but i think it is quite cheap and safe compared to use rockets to travel between asteroids, or manuever them to stabile orbits to connect them.
(Probably spinning won't be a single time investment, it makes docking harder, if the station has a non spinning dock, then regular delta-V is needed to prevent de-spin.)

Zero-g isn't ok for humans for a long time, bones atrophy... at this point we can only speculate, what 1/3 g does to humans, i don't deny, that if they want to return to Earth, it will be challenging... the question is whether the majority of them wants to return, or will be fine with a new place, and heavy training if they want to return?
Of course it is also a good question, whether humans will rather care about mining extraterrestial materials, or migrate in mass in order to find a new home with new possibilities?

 

[Pete Cortez]

"I hope we're not making decisions to settle places based on whether or not there's a horizon. As for a sky, this doesn't work?"

If we talk about permanent settlements, whether people feeling comfortable or not, is not negligable.

Then why assume that a Martian vista is more comfortable than a freefall settlement? At this point, there's far too many unknowns--including whether this is an important point at all--to debate aesthetics.

You need a pretty big tin can to have something like the sky.

You're going to need a big tin can period. Fortunately, there's a bunch of ready to assemble ones floating around the solar system.

I think we got pretty accustomed with building high towers in Earth gravity, once we landed on Mars, we can forget rockets, and use regular land vehicles and cranes in order to further expand.

Except for all the rockets needed to get all that material there in the first place. And what's wrong with rockets?

I'm not sure but i guess the delta-V needed to spin up asteroids is also enough to land on Mars.

From Mars orbit to the surface is four thousand meters per second of delta-v. A 1 g habitat with that sort of spin has a 1.6 million meter radius; at which point we might as well be cracking planets to build megastructures inhabited by quadrillions of people.

Construct roads, high-railways, build rovers that can go on rought terrain, yes it isn't that easy, but i think it is quite cheap and safe compared to use rockets to travel between asteroids, or manuever them to stabile orbits to connect them.

Constructing miles and miles of road is cheaper than throwing nuclear bombs out the back?

(Probably spinning won't be a single time investment, it makes docking harder, if the station has a non spinning dock, then regular delta-V is needed to prevent de-spin.)

1. A non-spinning dock is negligibly less massive than the spinning bulk. While there's still orders of magnitude difference, we don't worry about the slowing of Earth's spin.
2. You can always spin the ship.

Zero-g isn't ok for humans for a long time

Hence spinning.

Of course it is also a good question, whether humans will rather care about mining extraterrestial materials, or migrate in mass in order to find a new home with new possibilities?

I think the better question is what quality of life do humans aspire to have? Quality of life roughly correlates to access to energy and stuff to do things we want to do. There's a ton of energy and stuff in space.

 

[Drakkith]

Pete, I think I'm going to step out of this discussion. Enjoy.

 

[mfb]

From Mars orbit to the surface is four thousand meters per second of delta-v. A 1 g habitat with that sort of spin has a 1.6 million meter radius; at which point we might as well be cracking planets to build megastructures inhabited by quadrillions of people.

That comparison does not work.
Going from Mars orbit to the surface requires a heat shield, parachutes and small rockets with negligible delta_v. And you just need that for humans and things you cannot find on the martian surface. Material there does not need any rocket to get used.
Spinning up a habitat needs rockets for the whole final mass of your structure.

Constructing miles and miles of road is cheaper than throwing nuclear bombs out the back?

Yes. Nuclear weapons are expensive, and you would use them for every trip instead of a one-time investment.

 

[Pete Cortez]

That comparison does not work.
Going from Mars orbit to the surface requires a heat shield, parachutes and small rockets with negligible delta_v.

And you just need that for humans and things you cannot find on the martian surface. Material there does not need any rocket to get used.

My apologies. I meant from Earth orbit to Mars surface.

Spinning up a habitat needs rockets for the whole final mass of your structure.

Or slinging waste material anti-spinward.

Yes. Nuclear weapons are expensive, and you would use them for every trip instead of a one-time investment.

The actual warhead cost is not very high. The W-84 clocked in at $1-2 million per unit for a low production run of around 530. That includes amortization of R&D to produce the warhead in the first place, so it's unclear what the minimum unit cost might have been.

Also, I'm not proposing to use them for "every trip." I'm proposing to use them to spin up the habitat. That isn't the only way to do it[/quote], by the way.

 

[GTOM]

Using nuclear warheads?? Maybe it is only me, but i find this idea terrible...

I think the mass ratio of a non-spinning dock, and the spinning space station isn't negligable, like a car compared to Earth...

Of course rockets are needed, but i don't consider them cheap and more efficient than land travel and construction.
I don't see why hollow out an asteroid, making a large cylinder, build houses, spin the whole thing up, biogenic material collection, the delta-V for that operations, etc would be any easier than landing on Mars and use plane old engineering, and dome construction, and biogenic material collection from air and soil.

Yes having lots of energy is good, but won't make me happy if i have to spend my whole life in a tin can, instead of visiting a dozen cities and villages with my car, make small trips to the wilderness etc. (Energy isn't enough to propel rockets, and you can quickly run out of reactive mass on a small asteroid.) In order to feel good, people don't just need energy, but lots of material stuff also, a planet has magnitudes more material, housing space.

Pete, you mentioned lunar ghost towns... i see the very same possibility with asteroid colonies, once ore is depleted, it will be only a small settlement far away from trade routes... possibly they move the whole mining colony to another not too far asteroid, or desert it.

 

[Pete Cortez]

Using nuclear warheads?? Maybe it is only me, but i find this idea terrible...

I wouldn't necessarily use the exist stockpile. You'd probably want purpose-built explosives that direct as much power to the pusher plates as possible. But why do you find the idea terrible?

I think the mass ratio of a non-spinning dock, and the spinning space station isn't negligable, like a car compared to Earth...

Why wouldn't it be negligible? We're talking about a structure on the order of at least 1,000 times the mass of the ISS.

Of course rockets are needed, but i don't consider them cheap and more efficient than land travel and construction.

And I don't see ground transport cheaper or more efficient than slinging cable.

I don't see why hollow out an asteroid, making a large cylinder, build houses, spin the whole thing up, biogenic material collection, the delta-V for that operations, etc would be any easier than landing on Mars and use plane old engineering, and dome construction, and biogenic material collection from air and soil.

Quite simply, delta-v to and from said destination. Everything else is a second order concern. Is it possible you can think of some combination of Mars and asteroid settlement scenarios in which Mars initially starts at as a better prospect? Certainly. But the moment you start envisioning commerce with the homeworld or the rest of the solar system, Mars (or any other deeply gravitating body) becomes yet another well from which to climb out. And for what? For nothing you can't find in the rubble.

Yes having lots of energy is good, but won't make me happy if i have to spend my whole life in a tin can, instead of visiting a dozen cities and villages with my car, make small trips to the wilderness etc.

End of the day, Americans--on average--spend http://cfpub.epa.gov/eroe/index.cfm?fuseaction=list.listBySubTopic&ch=46&s=343 , so I think this is a very secondary point. However, each habitat offers you on the order of 100 square miles of surface area. You can have as many as you want to build. So build yourself a bunch of wilderness habitats. Drive around inside these colonies all you'd like, and simply hop a cable ferry over to the others in the bunch. We're basically talking about constructing an archipelago in space.

(Energy isn't enough to propel rockets, and you can quickly run out of reactive mass on a small asteroid.)

So get a large asteroid. Or many asteroids of many different sizes. The whole point is to exploit resources throughout the solar system. There's 6e20 kg worth of material in the Jupiter trojans.

In order to feel good, people don't just need energy, but lots of material stuff also, a planet has magnitudes more material, housing space.

All of it stuck at the bottom of a gravity well.

Pete, you mentioned lunar ghost towns... i see the very same possibility with asteroid colonies, once ore is depleted, it will be only a small settlement far away from trade routes... possibly they move the whole mining colony to another not too far asteroid, or desert it.

Once depleted, you've got real estate. And why bother moving real estate? There are very advantageous points in the solar system, and few are more advantageous than Earth-Lunar or Earth-Solar libration. Lots of energy, cheap to get to once you're off these godforsaken planets and perfect for staging missions to other interesting places in the Solar System. You move material to these locations, not the other way around.[/quote]

 

[GTOM]

Position asteroids (especially not so small ones) into positions so they can be connected with cables requires lots of delta-V, i think that energy is far enough to land on Mars, and build roads. If we can fly easily across the solar system i think we can somehow solve get out of the gravity well of a planet, even if we can't construct space elevators on smaller planets.
Energy : we can also build a solar panel forest on Phobos and Deimos and radiate energy to the surface.

Otherwise i have nothing against asteroid mines and docks, they can send lots of useful stuff to the planets.

90% indoor, yes i'am working indoor, and stay at home after work on weekdays, but i require regular travels also.

What i have against nukes? If you blow nukes in the vicinity of planets, fallback, otherwise i don't think it is an efficient method of propulsion, also don't think we should trust nukes to private persons (and i think private companies will have their role in space colonization)
Using nukes instead of regular TNT for mining purposes, well i heard they did such things in Sovietunion, but the radioactive waste don't make me calm...

 

[Pete Cortez]

Position asteroids (especially not so small ones) into positions so they can be connected with cables requires lots of delta-V, i think that energy is far enough to land on Mars, and build roads. If we can fly easily across the solar system i think we can somehow solve get out of the gravity well of a planet, even if we can't construct space elevators on smaller planets.

Mars is 4.1 m/s away. There are several NEAs within less than 1 km/s of low Earth orbit. These are Hohmann transfers, btw. You can probably find alternate routes to considerably more destinations. None of these options, however, help you ascent from a planet's surface. Which is why we should avoid being bound to one in the first place.

Energy : we can also build a solar panel forest on Phobos and Deimos and radiate energy to the surface.

You can do the same near Earth, and you have twice as much incident radiation as you do out by Mars.

Otherwise i have nothing against asteroid mines and docks, they can send lots of useful stuff to the planets.

If you're going to use them anyway, then why not live on them?

90% indoor, yes i'am working indoor, and stay at home after work on weekdays, but i require regular travels also.

The point is this problem is secondary. The other point is that there's no comparison between Earth's "outdoors" and that of Mars. The closest--and only crudely so--analogue would be hiking in Antarctica at polar night. If you absolutely need that experience, you're going to have to construct it, and again the choice boils down to first order considerations.

What i have against nukes? If you blow nukes in the vicinity of planets, fallback, otherwise i don't think it is an efficient method of propulsion, also don't think we should trust nukes to private persons (and i think private companies will have their role in space colonization)

So don't trust them to private persons. Set up an agency--the Bureau of Spinning Stuff--and have them use the nukes. Assuming you use nukes for this purpose. And I'm proposing using nukes hundreds of thousands to millions of miles away from planets.

Using nukes instead of regular TNT for mining purposes, well i heard they did such things in Sovietunion, but the radioactive waste don't make me calm...

Unless there's a good reason to atomize good mineral resources, I'm not advocating using nuclear explosives for mining.

 

[GTOM]

Ok, NEAs are near, that is good, they could serve as a good starting point, but the majority of asteroids are in the asteroid belt, farer from Mars, and aerobreak doesn't help. If you can position them into orbits so they can be connected by cables, then construct a martian space elevator is also far from impossible, so climb out from the gravity well will be far easier than now.

"If you're going to use them anyway, then why not live on them?"

Why don't use emptied mines for living on Earth? Of course the mining companies has to produce housing for necessary personnel, but IMHO high standard of living won't be a big concern, those habitats will be rather crammed places, since there is only a belt, that has uniform g-force, expansion is more difficult than on a planet.

Ok, so going out will be only the concern of adventurers, most people don't want to leave the gravity well neither, when they have an entire planet to colonize, explore, visit. So i think, that a number of asteroid mining colonies will send lots of ores to the planets, but the majority of people will choose the planets.

 

[mfb]

Building a martian space elevator (or many of them) is probably way easier than all those large-scale engineering projects discussed here.
Alternatively, the thin atmosphere might allow some direct ground-based launch structure.

If you're going to use them anyway, then why not live on them?

Why live on them? What do you do there once the valuable ressources are extracted and everything has to be imported?

 

[GTOM]

How easy or hard to dig deep into martian soil?
(I speculate about a south pole colony, i read the south pole shows signs of ozone, and has permanent cap of dry ice. )
If a probe or vehicle has strong enough batteries, how much could a sandstorm take away its vision, with all the dust and electricity?

 

[D H]

How easy or hard to dig deep into martian soil?

Trivial. Mars has no "soil". It has regolith.

In most places where humans live, you have dig a rather deep hole through the soil before you hit regolith. Soil on the Earth is chock full of organisms, most of which are very, very small. Humanity is still learning about the extreme importance of those microbes in the soil to the plants that grow in the soil.

 

[GTOM]

http://arstechnica.com/science/2011/04/mars-south-pole-holds-nearly-an-atmospheres-worth-of-co2/
www2.isunet.edu/index.php?option=com_docman&task=doc_download&gid=334

http://www.users.globalnet.co.uk/~mfogg/zubrin.htm

I received the following links about terraformation. I have tried to check obvious crackpottery, but sorry, I'm not qualified enough, i'd like to learn, whether they can be realistic or not, what are the main problems with them? (Provided we have lots of resource for colonization.)

 

[mfb]

There is no example of a thick CO₂ atmosphere to study, so the validity of climate models for that is at best questionable.
The proposed atmosphere is completely toxic for humans, which is certainly a disadvantage. Better than no atmosphere (no pressurized suit necessary, some cosmic ray protection), but the result is not a nice planet where we could walk around without oxygen supply.

 

[GTOM]

How much the atmosphere protects against UV-rays and other harmful radiation? (I know, not enough, but how serious rad protection should be needed?)

 

[newjerseyrunner]

We need machines that are capable of maintaining themselves I think. With advances in AI and robotics, I think the first people to walk on Mars are probably already born, the first people to live there for a lifetime is probably the generation after that.

 

[mfb]

How much the atmosphere protects against UV-rays and other harmful radiation? (I know, not enough, but how serious rad protection should be needed?)

Negligible. Protection against UV is easy, even a glass window is sufficient. Protection against high-energetic radiation needs more shielding.

 

[Generator Gawl]

Trivial. Mars has no "soil". It has regolith.

In most places where humans live, you have dig a rather deep hole through the soil before you hit regolith. Soil on the Earth is chock full of organisms, most of which are very, very small. Humanity is still learning about the extreme importance of those microbes in the soil to the plants that grow in the soil.

I'm not too sure on specifics if Mars has wind or not, but do you think that the regolith is on the surface because of the erosion of its surface soil it had originally? The current surface could have possibly had many meters of top soil on top before its magnetic field shut down and its atmosphere was mostly stripped. Share the info if you have it, I'd appreciate it greatly!

 

[Janus]

I'm not too sure on specifics if Mars has wind or not, but do you think that the regolith is on the surface because of the erosion of its surface soil it had originally? The current surface could have possibly had many meters of top soil on top before its magnetic field shut down and its atmosphere was mostly stripped. Share the info if you have it, I'd appreciate it greatly!

Mars definitely has winds. They can kick up dust storms which, from time to time, cover the whole planet for weeks at a time. Mars was in the middle of the largest one ever recorded in 1971 when Mariner 9 arrived. NASA had to wait a couple of months for it to clear before they could get images of the surface.