Feasibility Of Self-sufficient Martian Colony

arpc_01

26th October 2009 - 04:13 AM

I read somewhere that we could get to mars and establish a permanent settlement using only the technologies available to us right now IF we put enough money/resources into the project.

Is this true? If you had unlimited $ could you do it? Or is there problems that we just can't solve at the moment?

light in the tunnel

26th October 2009 - 04:26 AM

QUOTE (arpc_01+Oct 26 2009, 04:13 AM)

Put this in your application letter for a job in fiscal-stimulus politics. You'll get hired with a big salary!

My understanding is that Mars has large amounts of iron-oxide and chlorine. Rust and bleach are not my idea of the most environmentally-friendly substances, but theoretically you could set up a base by using solar power or geothermal power to extract oxygen from the rust, and if you could find water you'd be able to chlorinate a pool:)

I think that underground caves are the best way to set up bases on the moon or mars. You can send some kind of digging robot that runs on solar power from the surface and creates a network of corridors and living spaces, assuming the ground doesn't collapse.

What I wonder, though, is whether the geodiversity is sufficient to make it interesting for humans to live and work there for extended periods of time.

uaafanblog

26th October 2009 - 11:30 PM

A reasonably successful effort could be made to set up some sort of colony (really just a big "outpost") on Mars with our current technology.

The main problems with Mars are ...

Ineffective/Weak magnetosphere to protect against UV and/or charged particles ...
Temperature ... -190F to 65F is challenging ...
Pressure ... Liquid water can't be sustained in the low pressure atmosphere. It sublimates to a gaseous state immediately.

There are straightforward ways to overcome 2 of those main problems.

The UV problem means you stay indoors most of the time. UV rays are easily absorbed/deflected by any number of materials we have available. SOHO does a great job of detecting higher order particle storms that could be a big problem. You check the "space weather" often ... if the remnants of a CME are headed you're way you go into some sort of "bunker" to protect you. Humans have plenty of experience living that way ... just ask any Londoner that lived there in the first half of the 1940's.

Temperature variations are nothing new to humans. We live and work full-time at both poles on the earth which have "relatively" similar temperature changes. As for water ... extracting it into normal pressure habitats is probably a fairly simple activity (perhaps even just digging a well).

The only way to deal with the atmospheric pressure issue in a larger/longer term sense is via some sort of massive effort increase it. Such efforts with our current technologies and abilities would likely take multi-hundred year efforts to begin to make a dent.

Ultimately, trying to "geo-engineer" Mars is probably a useless effort. With no method to generate an effective magnetosphere; the atmosphere you lose to "space wind" would continuously be working against your efforts to build it. Maybe at some distant point in the future we could figure out a way to restart the failed "dynamo" inside Mars and generate a natural magnetosphere. But such a thing is well beyond our current capabilities.

Otherwise, I think all the chemistry you need is there. The soil as it is wouldn't require much management to grow food. The last real problem is the amount of time it takes to get there. Unless and until something like VSIMR is developed then you're stuck with round-trip times in multiples of "months" versus the "weeks" that you really need in order to get a colony effectively started.

There are no good candidates in our solar system for any sort of generalized colony. You could probably cool down Venus with C02 sequestration. A long process though ... the higher pressure atmosphere could probably be adapted to. But there appears to be little or no soil there and it's magnetosphere is basically useless too.

There's likely lots of water on several moons of Jupiter/Saturn. All of them present a wide array of challenges for Humans that are difficult if not impossible to overcome at this time and probably any time in the future.

The best bet (and I know there's others here that disagree with me) is to find an Earth-analogue around some other nearby main sequence star that is close enough to send a "fast" ship with something like 1,000 folks on it. Maybe in a couple of hundred years we'll be close to being able to do so. We'll likely find such a candidate though in the next decade or two.

John Galt

7th November 2009 - 04:16 PM

QUOTE (arpc_01+Oct 26 2009, 04:13 AM)

This is a concept strongly promoted by Zubrin with his Mars Direct project and described in his book The Case for Mars.

His basic thesis is to live off the land in the manner of early settlers in North America, obviously not in the literal sense as they did, but by utilising as many of the Martian resources as possible.

Thus rather than carrying the fuel for the return flight and for power while exploring the surface an automatic craft would land and with power supplied by a small reactor would extract gas from the atmosphere. Two years later, a manned craft would land. This cycle could be repeated at two yearly intervals and over time a base could be constructed and methods worked out for providing all necessities from local resources. At that point a true colony could be established.

Google Zubrin and MArs and you will find a host of links on the topic.

Enthalpy

8th November 2009 - 08:42 PM

Of course we could go to Mars! Von Braun already had technically working plans for it.

--- BUT ---

What do you mean by "if we put enough money"?

That's not just a matter of lack of good will! A few barriers:
- "Enough money" can mean "more than Mankind has"
- We have other objectives which need money for a more appreciable return...

Examples taken randomly:
- Replace fossil fuels
- Eradicate malaria
- Invent biotechnology

--- SO ---

it IS a matter of cost!

Mankind will some day say "hey, we've been able of doing it" just as a child says "I've been able of jumping from this wall" but only if this funny and worthless activity gets affordable enough, which still needs ideas. And I feel good use of money pretty much normal.

light in the tunnel

8th November 2009 - 09:41 PM

The question isn't if there is enough money or how much it would take. The issue is whether it is worth it to devote specific material resources and energy into specific projects.

For example, you could spend the rest of Earth's fossil fuel and nuclear fuel on creating enough liquid hydrogen to launch an entire lake's worth of water into space and transporting it to mars. The question is whether it would be worth losing all Earth's energy reserves to move some of its water to Mars.

The better question than whether it would be possible by spending enough money is if there are enough low-cost strategies for colonization available to convince people to invest in a slow process of colonization and/or terraforming. Whoever posted that the general model to follow would be that of early settlers of N America, i.e. taking as little as possible and building on what's available from the existing Martian environment has the right perspective, imo.

light in the tunnel

8th November 2009 - 09:49 PM

I think the best use of interplanetary colonization resources would be to set up a large, biosphere-type greenhouse on the moon that could basically simulate a few acres of terrestrial land. This could be developed into a moon resort for the very rich and people with muscle-diseases who would benefit from being able to walk and engage in other physical activities more easily in a lower gravity environment.

It would also be neat to see how trees and plants would grow in the gravity of the moon.

Oh, BTW, I posted this on another thread but no one gave an answer. If water sublimates easily in the low pressure atmosphere of Mars, what does it do on the moon with no atmosphere? I assume that without any air to dissolve into, it could not evaporate. Would it then fall to the ground? Would it be liquid, solid, or gas? If gaseous, due to lack of pressure, would it still freeze due to the cold (when it's dark) and, if so, what does frozen steam look like? Granules? Does water have surface tension without atmospheric pressure?

FlyingSpaghettiMonster

11th November 2009 - 09:37 PM

QUOTE (light in the tunnel+Nov 8 2009, 09:49 PM)

Oh, BTW, I posted this on another thread but no one gave an answer. If water sublimates easily in the low pressure atmosphere of Mars, what does it do on the moon with no atmosphere? I assume that without any air to dissolve into, it could not evaporate. Would it then fall to the ground? Would it be liquid, solid, or gas? If gaseous, due to lack of pressure, would it still freeze due to the cold (when it's dark) and, if so, what does frozen steam look like? Granules? Does water have surface tension without atmospheric pressure?

Water doesn't need air to "dissolve into" to evaporate. So, if you left a bucket of water on the moon, it'd simply boil away. Actually, the process of going from liquid to gas would carry away heat (the same reason sweating cools you down as it evaporates from your skin), so the water remaining in the bucket would get colder as part of it boiled off, to the point where it would end up freezing. The remaining ice would sublimate when heated by the sun, like how dry ice does on earth.

What the final fate of the water vapor on the moon would be, I'm not sure. It'd probably be so thin that it'd be more worthwhile to think of it as a collection of individual particles than as a gas. So, they'd probably bounce around on the surface for a while until they picked up enough energy (from a photon from the sun or a warm rock, I don't know) to get launched into space or broken apart into hydrogen and oxygen. Just guessing here.

light in the tunnel

12th November 2009 - 12:02 AM

Huh, I assumed that gaseous particles on the moon would evaporate, in the sense that the molecules wouldn't have any reason to stop expanding outward, but I also don't see why they would continue going up without falling down to the surface. After all, gravity is present albeit less than that of Earth.

My hypothesis would be that any gaseous molecules on the lunar surface would form a very thin atmosphere close to the ground. I guess the depth of the atmosphere would be determined by the amount of heat conveyed to them as they fall to the ground. Maybe you could measure Lunar atmosphere according to the maximum height reached by gaseous molecules before gravity pulls them back down? I'm confused thinking about this because in the terrestrial atmosphere there are enough molecules present to stack up on each other in layers and create relatively uniform pressure/density that translates gravity directly into pressure that resists the molecular motion caused by heating.

Wouldn't there be SOME atmospheric pressure on the moon, because it has gravity? If nothing else I would expect similar particles to what floats around in space, but then at a density proportional to the gravity. Or is it possible for gas to be heated up by surface temperature and somehow just "blow away?"

FlyingSpaghettiMonster

12th November 2009 - 02:20 AM

Well, someone else could probably answer it more specifically with actual calculations, but the temperature of a gas is directly related to the average kinetic energy of the particles in it. If the gas is of any appreciable density, then the individual particles are hitting each other frequently and constantly changing direction, so no particle is ever actually moving too far from its starting point in a given amount of time. But if it's not running into another particle, it's going to just keep on going. I can't give you a specific figure, but I'm thinking that an individual particle the mass of a water molecule is going to be moving surprisingly fast at (let's say) room temperature. Maybe not enough to escape the moon's gravity, though, but I'm pretty sure it's enough that they won't pool up in a millimeter-thick layer on the surface.

The thing is, though, is that the individual particles in a gas all have different energies. Some are above the average, and some are below. When collisions between particles of different energies occur, it tends to have an averaging effect, but not always. If, for example, a slow particle broadsides a faster one, the faster one could actually gain energy at the expense of the slower one. So, I'm sure there's some sort of distribution of velocities involved here. Every now and again, a particle might gain enough energy to escape the moon. How often, I don't know.

I'm thinking if the water molecules are escaping the moon, it's probably more from the solar wind than anything else.

Anyone here feel comfortable doing some calculations? I was getting about 640 m/s for a water molecule (ignoring molecular vibration) at 293 K, but it's been a long time since I've done this sort of stuff. For hydrogen atoms, I got about 2700 m/s, well above the 2380 m/s escape velocity required for the moon. For hydrogen molecules, I got about 1900 m/s, which seems close enough for plenty of "above average" molecules to escape.

light in the tunnel

12th November 2009 - 03:17 AM

Thanks for the clear explanation of KE and velocity distribution among gaseous particles. It has me wondering whether collisions between particles are even a factor on the moon. Could gaseous molecules be so far apart that they would just bounce around on the surface most of the time and rarely collide with other gas molecules?

QUOTE

I'm thinking if the water molecules are escaping the moon, it's probably more from the solar wind than anything else.

Why, because the solar wind particles would knock the water molecules beyond escape velocity like billiard balls?

QUOTE (->

QUOTE

I'm thinking if the water molecules are escaping the moon, it's probably more from the solar wind than anything else.

Why, because the solar wind particles would knock the water molecules beyond escape velocity like billiard balls?

Anyone here feel comfortable doing some calculations? I was getting about 640 m/s for a water molecule (ignoring molecular vibration) at 293 K, but it's been a long time since I've done this sort of stuff. For hydrogen atoms, I got about 2700 m/s, well above the 2380 m/s escape velocity required for the moon. For hydrogen molecules, I got about 1900 m/s, which seems close enough for plenty of "above average" molecules to escape.

I got as far as looking up lunar gravity (@1.6 m/s^2). Then I can't figure out how to set up the equation for deceleration. Does dividing 640 m/s by 1.6 give the number of seconds or meters before the velocity is 0? Or does the acceleration formula have to be differentiated by multiplying the 1.6 by the 2 from the exponent? It's been a long time since I've done math, as you can see. The logic of the equations made sense to me at the time, but now I just remember that acceleration is rate of change in velocity.

Either way, I'm imagining water molecules on the moon bouncing around at a height of several hundred meters. I wonder how much lower this altitude would be on the dark/cold side.

FlyingSpaghettiMonster

12th November 2009 - 05:48 AM

QUOTE

Well, yeah, that's what I'm thinking, anyway.

QUOTE (->

QUOTE

Well, yeah, that's what I'm thinking, anyway.

Why, because the solar wind particles would knock the water molecules beyond escape velocity like billiard balls?

Yep. That and/or break them apart. The hydrogen would probably escape pretty easily at that point, and the oxygen would probably bond with the rocks.

QUOTE

You're on the right track here, I think, if you're trying to figure out the average height the particles will reach. (Well, assuming they're travelling straight up, which they won't be, but it gives us at least a sense of the big picture.)

V_final = V_initial + A * t

V_final = 0 m/s (i.e., it pauses at the top of its journey)
V_initial = 640 m/s (if I didn't screw it up)
A = -1.6 m/s^2 (negative because it's in the
opposite direction of the initial velocity)
t = time

0 m/s = (640 m/s) + (-1.6 m/s^2) * t
-640 m/s = (-1.6 m/s^2) * t
t = (-640 m/s) / (-1.6 m/s^2)
t = 400 s

You were asking if the units were seconds or meters. Besides the obvious point that time is measured in seconds, you could try fiddling with the units to see how it comes out. (m/s) / (m/s^2) = (m/s) * (s^2/m) = (m * s^2) / (m * s) = s. Dimensional analysis is a good skill to have; if it came out to something other than seconds, you'd know to go back and check your work.

So, now, a time of 400 s, you can try to calculate the height:

X_final = X_initial + V_initial * t + (1/2) * A * t^2

X_final = final height
X_initial = 0 m (ground level)
V_initial = 640 m/s
A = -1.6 m/s^2
t = 400 s

X_final = (0 m) + ((640 m/s) * 400 s) + ((1/2) * (-1.6 m/s^2) * (400 s)^2)
X_final = (256000 m) + (-128000 m)
X_final = 128000 m = 128 km

The moon's radius is about 1700 km, so 128 km is large enough that we *could* consider reworking the problem without assuming acceleration is constant, if we're really worried about accuracy. Anyway, since gravity is decreasing with height, we know that the real answer has to be greater than 128 km.

QUOTE (->

QUOTE

Looks like a lot more than several hundred meters, now that I've worked it out. Wikipedia says that the moon's surface temperature varies from about 100 K to 390 K at the equator, so... just trying to figure it out in my head here... a factor of four in temperature means a factor of four in energy, which means a factor of two in velocity, which means a factor of four in height. I guess it comes out proportionate to temperature. I used 293 K in my initial figures, so, (100/293)*128 km = 44 km at the low end, and (390/293)*128 = 170 km at the high end.

adoucette

12th November 2009 - 09:16 PM

I think a related question is:

About what would be the minimal number of people that would be needed at a self sustaining colony?

Assumption:

There is a supply ship each year which can bring a limited amount of equipment to the colony, say 4,000 lbs worth.

First Question? What would you ship from earth?

Also there is no, or very limited ability to return to earth, and in any case, one can't return quickly, so emergencies and medical care has to be handled on site.

We presume that only adults will start out, but there will be couples and thus babies etc over time (but don't count kids in number).

We presume that there is sufficient O2 and water for basic needs on mars and doesn't need to be imported, but they do need to be recycled.

Everything else, energy production, food production, livestock, food preservation, butcher, baker, cooking, manufacturing, electrical work, heating, cooling, plumbing, clothing, cobbler, space suits, equipment repair, fabrication, Oxygen, Water recycling, waste recycling, local entertainment, recreational activities, new structures, medical care, teaching, day care, sanitation, legal advice, law enforcement, spiritual needs, mortuary services etc etc has to be handled by the colony members.

So, 10 people, 100 people or 1,000 and why?

Arthur

light in the tunnel

13th November 2009 - 03:50 AM

QUOTE (FlyingSpaghettiMonster+Nov 12 2009, 05:48 AM)

That makes sense that you can cancel out the units in the algebra and end up with seconds as the unit of the answer. I think I knew that but I forgot.

I also didn't think about gravity getting weaker as altitude increases. Now that you've basically established that any surface water on the moon would sublimate and bounce around many km high, my question becomes how any water/ice would ever tend to collect anywhere on the moon without an atmosphere to force it downward? Plus if there's not enough water to generate enough humidity for condensation to occur, how would water end up on or in the ground even if their was an atmosphere?

Same question with regards to Mars. If the atmosphere is too thin or dry, how would water ever do anything other than evaporate? If there was any water present, wouldn't it be in the form of clouds or at least very slight humidity?

RobDegraves

13th November 2009 - 04:27 AM

QUOTE

my question becomes how any water/ice would ever tend to collect anywhere on the moon without an atmosphere to force it downward?

There is a lot of water in the universe.

Hydrogen has been detected in interstellar clouds, produced as a by product of star formation and is found all over our solar system.

Comets are largely balls of dirty ice.

Even if the Moon didn't produce water, there would have been millions of tons of it hitting the Moon over the billions of years in the way of comets, debris, etc.

Mars is largely believe to have had an atmosphere at some point in it's past. If it did, it would have likely had water.

Any of the water on the surface would be long gone, however some of the water underneath the ground may still remain.

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