Could a human colony thrive on mars?

[Corsair 115]

I tend to think the biggest limit is launch vehicle capacity. If you can lift it, you can put a lead wall between the sun and the crew.

The choice there though is whether to design and build a really big booster with an enormous capacity so you can get a lot of material into orbit with as few launches as possible, or design and build a smaller booster with a lower capacity and have more launches to get the material into orbit and then assemble it all together there.

 

[Correa Neto]

I do mean terraforming. I mean an actual civilization of self sustaining human beings living on Mars and glad they live there. I wouldn't like to live there but would it be possible for this to happen someday?

I think it is possible, but not anytime soon. Some major breakthrougs in many areas are required. Also, terraforming, from the little stuff I read about, seems to require a few thousands of years to be completed. Even "dome cities" are, I think, very far away in the future.

 

[Jimbo07]

The choice there though is whether to design and build a really big booster with an enormous capacity so you can get a lot of material into orbit with as few launches as possible, or design and build a smaller booster with a lower capacity and have more launches to get the material into orbit and then assemble it all together there.

Well, that's not the only important choice, per se. There are also questions regarding single vs. multi-stage, specific impulse of fuels, reusability, etc. I don't know which question comes first, because I've never been a project manager on a rocketry program.

I suspect that the most fundamental underlying question of design philosophy is: how do we get the most stuff up this gravity well economically?

Space Elevators, baby...

...

BTW, I've been to the Ruby.

 

[ConspiRaider]

I do mean terraforming. I mean an actual civilization of self sustaining human beings living on Mars and glad they live there. I wouldn't like to live there but would it be possible for this to happen someday?

Sci-fi aficionados love to throw around the word "terraforming" in the same manner they throw around "warp drive". At some point, distinctions between fact and fiction blur, and you find people discussing these items as if their implementation is mere triviality.

Mars: Its atmospheric pressure is about 1% that on Earth. You, for example, do not explode outward because internally, your body is applying approximately 14.7 pounds per square inch of outward pressure. Which is met by approximately 14.7 pounds per square inch of atmospheric pressure (at sea level). Equilibrium. Your insides stay inside and your outsides meekly stay outside.

On Mars, you'd explode outward.

If you weigh 150 pounds here on Earthola, you'd weigh the equivalent of 50 pounds on Mars. Nobody knows - no one - all the types of long term devastation that might occur in the human organism at one third gravity. For sure though, bone loss. Our bones need the stress of gravity - Earth gravity - to maintain density. That's just one factor. What other types of havoc could occur? We really don't know. We'd need human guinea pigs to establish the data. Any volunteers?

The air on Mars has about the same percentage of carbon dioxide as the air on Venus: About 95%. So obviously we would have to fill the entire planet of Mars with an air mixture approximating that on Earth: About 78% nitrogen, about 21% oxygen, and a mixed bag of other stuff, mostly carbon dioxide. How many millennia would it take to do that? I haven't the slightest. And how can we be assured that once the new atmosphere is created - it'll stay put? Mars does not have the gravity of Earth. That nuevo atmosphere might just drift off into space.

Temperature? Well, great variance. Think COLD and you'll be mostly right. And how would the temperature be affected by this artificial atmosphere that we generated? Would it make the planet cooler? Hotter, like Venus? We have no clue, not really. Computer models are fine but... we don't even know, with all our knowledge, exactly how OUR OWN planetary weather system functions. Too many variables. So, what if we spent 5,000 years generating an Earth-friendly atmosphere for Mars - and then find out that it raises the surface temperature to 400 degrees Fahrenheit?

A bubble. An artificial bubble is the only feasible way humans could ever live on Mars. For a novelty? A little vacation, to brag about at the company picnic back on Earth? Exploration? Fine. But nothing permanent. Except maybe a prison.

 

[Cuddles]

If you weigh 150 pounds here on Earthola, you'd weigh the equivalent of 50 pounds on Mars. Nobody knows - no one - all the types of long term devastation that might occur in the human organism at one third gravity. For sure though, bone loss. Our bones need the stress of gravity - Earth gravity - to maintain density. That's just one factor. What other types of havoc could occur? We really don't know.

And yet you have no problem talking about people essentially living in space or on asteroids, where the problem is much, much worse. One of the main reasons Mars is a popular idea is because it's sort of a halfway house. On Earth, we have gravity, air and an environment. In space you have none of them. On Mars you have less gravity, less air and a hostile environment, but they're all still there, and so conditions will (probably) be much easier than making the jump straight to space.

We'd need human guinea pigs to establish the data. Any volunteers?

We call them "astronauts".

 

[BeAChooser]

On Mars, you'd explode outward.

Sorry to disillusion you...

http://www.sff.net/people/Geoffrey.Landis/vacuum.html "How long could a human survive if exposed to vacuum? Would you explode? Would you survive? How long would you remain conscious? The quick answers to these questions are: Clarke got it about right in 2001. You would survive about a ninety seconds, you wouldn't explode, you would remain conscious for about ten seconds."

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970603.html " How would the unprotected human body react to the vacuum of outer space? Would it inflate to bursting? or would it not? or would just the interior gases hyperinflate? ... snip ... If you don't try to hold your breath, exposure to space for half a minute or so is unlikely to produce permanent injury. Holding your breath is likely to damage your lungs, something scuba divers have to watch out for when ascending, and you'll have eardrum trouble if your Eustachian tubes are badly plugged up, but theory predicts -- and animal experiments confirm -- that otherwise, exposure to vacuum causes no immediate injury. You do not explode. Your blood does not boil. You do not freeze. You do not instantly lose consciousness."

And that's in a vacuum.

 

[Jimbo07]

Exploration? Fine. But nothing permanent.

Sustained exploration may require a small semi-permanent support base. Factory modules capable of utilizing local resources would be a valuable asset... on Mars or on your asteroid missions.

Except maybe a prison.

'Back' to the future, eh?

 

[ConspiRaider]

And yet you have no problem talking about people essentially living in space or on asteroids, where the problem is much, much worse. One of the main reasons Mars is a popular idea is because it's sort of a halfway house. On Earth, we have gravity, air and an environment. In space you have none of them. On Mars you have less gravity, less air and a hostile environment, but they're all still there, and so conditions will (probably) be much easier than making the jump straight to space.

We call them "astronauts".

First, astronauts are NOT human guinea pigs. They are temporarily in space to perform work - and then they come home.

Second, you are jumping to huge conclusions. You really didn't read or comprehend anything in my above discussion. Hey - Venus has gravity, air and a hostile environment too. Yet it's called Earth's twin. Want to go to Venus? Shorter distance. Pretty much the same size as our planet. Oh wait. Surface temperature is about 900 degrees Fahrenheit, from what we can tell. Oh wait wait. Atmospheric pressure on Venus is about 90 times that of Earth's. So whereas on Mars you'd explode outward, on Venus you'd be squashed flat.

In a space vehicle of long term habitation - we'd have to simulate gravity. That would be done via centrifugal force, such as the extra g's produced when an F-14 Tomcat fighter makes a tight turn at high speed. A hollowed-out asteroid, for example, would not be like a beach ball, mostly empty within. The hollowing out would be a section a certain distance below the outside surface. That's where passengers would live - close to the surface. In that way, the imparting of a spin to the asteroid will produce the most centrifugal force, the furthest away from its center.

Nobody said this was gonna be easy. Tremendous difficulty. But it is far more feasible - far more - to create long term habitation space vehicles than it is to try and make-pretend that Mars is just a smaller Earth requiring a bit of tweaking and tuning. Mars is inhospitable for human life, animal life, plant life. That's how it is.

 

[ConspiRaider]

Sorry to disillusion you...

http://www.sff.net/people/Geoffrey.Landis/vacuum.html "How long could a human survive if exposed to vacuum? Would you explode? Would you survive? How long would you remain conscious? The quick answers to these questions are: Clarke got it about right in 2001. You would survive about a ninety seconds, you wouldn't explode, you would remain conscious for about ten seconds."

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970603.html " How would the unprotected human body react to the vacuum of outer space? Would it inflate to bursting? or would it not? or would just the interior gases hyperinflate? ... snip ... If you don't try to hold your breath, exposure to space for half a minute or so is unlikely to produce permanent injury. Holding your breath is likely to damage your lungs, something scuba divers have to watch out for when ascending, and you'll have eardrum trouble if your Eustachian tubes are badly plugged up, but theory predicts -- and animal experiments confirm -- that otherwise, exposure to vacuum causes no immediate injury. You do not explode. Your blood does not boil. You do not freeze. You do not instantly lose consciousness."

And that's in a vacuum.

Then I invite you, BAC, to try this out yourself!

Explosiveness is a relative term here. On Mars, your insides will be trying their damndest to get OUT. Betcha it'd be horrifically painful. For my money? I'd prefer a quick big bang.

 

[BeAChooser]

Explosiveness is a relative term here.

Sorry, but your description of the problem:

"You, for example, do not explode outward because internally, your body is applying approximately 14.7 pounds per square inch of outward pressure."

shows a lack of understanding of physics and anatomy. Remove the air around us and there is NOT 14.7 psi of outward pressure inside us (except perhaps in the lungs, and that is why they recommend you don't hold your breath if you find yourself suddenly in vacuum).

 

[patnray]

I tend to think the biggest limit is launch vehicle capacity. If you can lift it, you can put a lead wall between the sun and the crew.

Proof that you really don't understand the enormous challenges. The danger is from both cosmic rays and solar storms. Lead shielding would make the problem worse. Cosmic ray collisions with the lead would produce a stream of secondary ionized particles. Even several feet of lead would not be enough protection. On Earth it is the large envelope of atmosphere that protects us. In near Earth orbit the Earth's magnetic field provides substantial protection. Travelers to Mars would face significant radiation exposure during the trip and once on Mars (which has too thin an atmosphere and no magnetic field). It turns out that a large water tank would provide much better crew protection than lead...

While the martian atmosphere is too thin to provide much protection, it is thick enough to make landing large spacecraft nearly impossible. So many smaller landers, rather tahn one large craft, would be more practical.

OTOH, the thin atmosphere and lower gravity makes getting off Mars much easier. Assuming sufficient electrical generation capacity, spacecraft leaving Mars could acquire significant velocity from a magnetic "cannon" before firing the rocket motors (like the linear induction propulsion used in some roller coasters, but on a gigantic scale...)

The challenges are enormous. For the near future we will get far more ROI from developing robotic exploration systems. Since this technology will be crucial to any future manned missions, we don't really lose anything by working on those systems first. We do lose lots, however, by concentrating most of our space budget on manned mission. Dozens of worthwhile unmanned projects are being scrapped or delayed because the manned projects consume so much of the budget.

 

[jimbob]

Proof that you really don't understand the enormous challenges. The danger is from both cosmic rays and solar storms. Lead shielding would make the problem worse. Cosmic ray collisions with the lead would produce a stream of secondary ionized particles. Even several feet of lead would not be enough protection. On Earth it is the large envelope of atmosphere that protects us. In near Earth orbit the Earth's magnetic field provides substantial protection. Travelers to Mars would face significant radiation exposure during the trip and once on Mars (which has too thin an atmosphere and no magnetic field). It turns out that a large water tank would provide much better crew protection than lead...

While the martian atmosphere is too thin to provide much protection, it is thick enough to make landing large spacecraft nearly impossible. So many smaller landers, rather tahn one large craft, would be more practical.
<snip>
The challenges are enormous. For the near future we will get far more ROI from developing robotic exploration systems. Since this technology will be crucial to any future manned missions, we don't really lose anything by working on those systems first. We do lose lots, however, by concentrating most of our space budget on manned mission. Dozens of worthwhile unmanned projects are being scrapped or delayed because the manned projects consume so much of the budget.

Which is why I said water...

I think robots would have to prepare any manned landing, landing the base and assembling it, so the crew aren't limited to a single LEM type vehicle. If one could set up the base infrastructure before any astronauts arrived that might make it more feasible...


"Dozens of worthwhile unmanned projects are being scrapped or delayed because the manned projects consume so much of the budget."

Agreed

Sorry, but your description of the problem:

"You, for example, do not explode outward because internally, your body is applying approximately 14.7 pounds per square inch of outward pressure."

shows a lack of understanding of physics and anatomy. Remove the air around us and there is NOT 14.7 psi of outward pressure inside us (except perhaps in the lungs, and that is why they recommend you don't hold your breath if you find yourself suddenly in vacuum).

Would the low partial pressure of oxygen be such that suffocation would be very quick; i.e would the blood lose oxygen like [rule8] off a shovel, or would the oxyhaemoglobin stop that?

 

[Jimbo07]

Proof that you really don't understand the enormous challenges.

*sigh*

jimbob already addressed this. I really wish I had said water in the first place.

My point had much more to do with lifting than with the nature of the shield itself. Fine. We'd have to lift a lot of water. Frankly, we could make the shield out of cheddar cheese for all I care, but lifting it would still be a problem.

While the martian atmosphere is too thin to provide much protection, it is thick enough to make landing large spacecraft nearly impossible. So many smaller landers, rather tahn one large craft, would be more practical.

Possibly. I wasn't really addressing the final stage strategy.

The challenges are enormous.

No argument from me...

For the near future we will get far more ROI from developing robotic exploration systems. Since this technology will be crucial to any future manned missions, we don't really lose anything by working on those systems first. We do lose lots, however, by concentrating most of our space budget on manned mission. Dozens of worthwhile unmanned projects are being scrapped or delayed because the manned projects consume so much of the budget.

This sounds familiar. Haven't we been over this before? I'm not looking to get back involved in the fully human vs. fully robotic exploration debate.

 

[jimbob]

And the space agencies are proposing magnetic shielding for lunar missions

 

[Hellbound]

jimbob:

That's great, but is there really that much danger from magnets?



Seriously, though, I can see where this would help against charged particles, but I don't see this stopping, for example, gamma radiation, neutral particles, micrometeorites, and other bits of neutral debris and/or non-charged radiation. I wonder how well this would work?

Got any additional info on it?

 

[ConspiRaider]

Sorry, but your description of the problem:

"You, for example, do not explode outward because internally, your body is applying approximately 14.7 pounds per square inch of outward pressure."

shows a lack of understanding of physics and anatomy. Remove the air around us and there is NOT 14.7 psi of outward pressure inside us (except perhaps in the lungs, and that is why they recommend you don't hold your breath if you find yourself suddenly in vacuum).

Then tell it to Wiki, and update that entry:

At sea level, the Earth's atmosphere actually exerts a force of 14.7 psi on all surfaces (see below). Humans do not feel this pressure, because internal pressure of liquid in human body matches the external pressure.

http://en.wikipedia.org/wiki/Pound-force_per_square_inch

 

[Hellbound]

The Wiki entry is more-or-less correct (if not complete)

However, the human body, specifically it's containment system, is not rigid. It is highly elastic. The internal pressure varies in response to the external pressure.

By the reasoning you're using, people climbing Mt. Everest should have ears and limbs being blown off (pressure at the summit is about 1/3rd that of sea level). You'd also see explosive deaths from HALO jumps.

 

[ConspiRaider]

The Wiki entry is more-or-less correct (if not complete)

However, the human body, specifically it's containment system, is not rigid. It is highly elastic. The internal pressure varies in response to the external pressure.

Yep.

But that means we're still in a terrible (and horrifically painful) fix when we step onto the Martian surface in Bermuda shorts and sandals. Let's see, 1% of 14.7 psi is um...

.147 pounds per square inch from the Martian atmosphere.

Get me to Venus. At least I'll be crushed before my brain registers the pain (hopefully).

 

[Hellbound]

Actually, with a helmet and air supply, it wouldn't hurt you at all (at least not for some time). Add something like a wetsuit and you'd be fine.

Your body responds to pressure. The danger of vacuum primarily comes from it's effects on lungs and eyes. You're vastly over-exaggerating the effects of low pressure.

ETA: Now, I'm assuming you take reasonable precautions of depressurizing/repressurizing slowly. Explosive decompression/rapid decompression is a different story, but in those cases the damage isn't from low pressure, but the rapid onset of low pressure.

 

[ConspiRaider]

Actually, with a helmet and air supply, it wouldn't hurt you at all (at least not for some time). Add something like a wetsuit and you'd be fine.

Your body responds to pressure. The danger of vacuum primarily comes from it's effects on lungs and eyes. You're vastly over-exaggerating the effects of low pressure.

But the whole point of this thread was humans living on Mars in colonies without any artificial support for everyday living.

I'd hate it. REALLY hate it.

My ears go absolutely nail-in-the-eardrum nuts in a so-called "pressurized" jet airplane. Once when we landed - both ears were screwed up for a month, each.

Same with underwater. I can feel that pressure pushing in on my ears if I dive more than several feet deep.

So everyone has certain tolerances and variabilities. But none of us - none - could handle the atmospheric pressure of Mars for very long, totally unprotected. It'd be maybe the most horrific death imaginable.

I want Venus. At about 1300 pounds of pressure per square inch, it'd be lights out, but quick. I think. I call dibs on testing Venus first when we get there, okay? You can have first dibs on Mars. No cheating, I called Venus first! I'm telling Mom!