What is up with Mars?

[Grimfilth]

Self sufficiency could work in the long run on Mars, but i doubt it'll be worth the effort, looking at how humanity is single handedly destroying this planet already.

[Nibb31]

Self sufficiency and closed-loop life support are hard. In fact, it's so hard that we haven't even got it to work on Earth.

If we can build self-sufficient colonies on Mars, we can build them in the Gobi desert or under the sea for a fraction of the cost. There is no point in going to Mars.

[*Aqua*]

• Mars core isn't cold, and there's plenty of speculation about current volcanic activity on Mars. Though yes - lack of a proper magnetosphere is certainly one of the biggest obstacles in colonizing Mars.
  

• Mars next to the moon is the easiest location to colonize allowing us to not only mine resources but also refine them sending back to earth high quality products - something that's difficult to achieve by mining asteroids or the moon (moon also got different composition than mars and is far less suitable for sustaining larger mining operations - mostly due to limited supply of water). That however would require a significant effort that very likely will be impossible to achieve any time soon (eg. at a very least you'd need to be able to refuel rockets on a mars that can fly back to Earth - which means production of rocket fuel on another planet - something extremely difficult on it's own)
  
• Point of having a place to live is to have a place to live on another planet. In case of a catastrophic event it'd prevent the demise of human kind. Living in oceans doesn't guarantee that. Moon is closer, but moon is also a very risky place to live on - single micrometeorite shower can wipe such colony out of a surface in a seconds. Mars has an atmosphere which is a game-changer.
  

That's the first time I heard about possibly active vulcanos on Mars. Afaik there is no tectonic activity or at least there wasn't for a couple millions or billions years.

Mars is imo a bad source for mining. There is the huge gravity well you'll have to overcome each time you want to send stuff to Earth. The thin atmosphere is also in the way.

Mining asteroids is far easier. You don't have to think about an atmosphere or gravitation. Asteroids come in all sizes and compositions so you can mine according to what and how much is needed. It could be that sending whole asteroids to process them on the moon or in Earth's orbit is cheaper than sending a complete mining facility into deep space. I see a lot of potential in asteroids.

Mars on the other hand always means you'll have to fight atmosphere and gravity. I can't stress this enough because they're huge drawbacks for any kind of doing.

I can't agree to Mars as a safe haven in case of catastrophic events on Earth. Mars colonies will most likely always depend on supplies from Earth - I guess at least for centuries. So if Earth dies, Mars will die, too.

Terraforming it would be very difficult. The nitrogen is not a big problem, we could live pretty well with pure O2 at 02bar, but there is a massive lack of hydrogen, and we'll need a lot of it to get water and biomass.

[...]

Oh, and He3 is rubbish as a fusion fuel (more difficult to fuse than DT, and still not aneutronic), and is super rare in the Moon's crust, so you'd need to process massive amounts of rocks to get a few g of the stuff, it's not sure you could break even. That being said, we'll have permanent settlements on the Moon before we have them on Mars simply because it is easier.

I have a link to a site where they analyse different approaches to terraforming Mars. Unfortunately there is a 500 server error.

I summarized the discussed methods here: http://forum.kerbalspaceprogram.com/threads/70211-Terraforming-Mars?p=1013567&viewfull=1#post1013567

Terraforming a planet is far beyond our technology, not to mention is it wasteful and foolish. Planets are inherently problematic because of their gravity wells as well as sheer scale. Space based colonization is a far better alternative.

Quoted for truth.

If we can build self-sufficient colonies on Mars, we can build them in the Gobi desert or under the sea for a fraction of the cost. There is no point in going to Mars.

True. If we can do that, there is no reason to go to a planet anymore. Everything we need can be obtained in the asteroid belt and from the sun.

[-Velocity-]

I disagree about colonization being out of the question.

Mars spins fast enough and has low enough gravity to build a functional space elevator quite "easily". We might never get one working on Earth, but it should already be possible on Mars. We might have to destroy or move Phobos though- but Phobos is small enough that this is not out exceedingly difficult. But if we get space elevators on Mars, Mars could serve as a vast mining base for space-based construction, as we could easily get materials mined on the surface into orbit via the elevators.

[KerikBalm]

I looked into this before, and the best analysis of loss by thermal diffusion I've found is reproduced in this post: http://forum.kerbalspaceprogram.com/threads/70211-Terraforming-Mars?p=988493&viewfull=1#post988493

That was assuming an average temperature of -40C, assumes even temperature distribution - the rate of loss when its warmer will not be compensated by the reduced rate when it is colder, and of course, ignores the solar wind - which admittedly is hard to model. It also assumes the gas is never significantly disassociated into smaller compounds.

Anyway... it lacks nitrogen now... where do you propose getting enough to rebuild Mar's atmosphere?

-Although you could stubstitute Argon/Krypton/Xenon for a lot of N2, to truly terraform, it needs to have a N2 atmosphere so that life can fix nitrogen.

[Kryten]

-Although you could stubstitute Argon/Krypton/Xenon for a lot of N2, to truly terraform, it needs to have a N2 atmosphere so that life can fix nitrogen.

Argon, as an inert gas with pretty similar density to oxygen and nitrogen, is going to be pretty much absent on mars for the same reasons they are. Xenon and krypton are simply too rare to be significant components of an atmosphere.

[KerikBalm]

Argon has a MW of 40

N2 has a MW of 28.....

CO2 has a MW of 44...

What were you saying?

[Kryten]

Molecular weight is not density, which is roughly intermediate between CO2 and O2. How would you be supposed to add more, anyway? It's a noble gas with boiling point well above the average temperature, all the argon on Mars is going to already be in the atmosphere.

[Nibb31]

I disagree about colonization being out of the question.

Mars spins fast enough and has low enough gravity to build a functional space elevator quite "easily". We might never get one working on Earth, but it should already be possible on Mars.

Mars' geostationary (or "areostationary") orbit is 17000km, which is only marginally easier than the 36000km orbit required for an Earth space elevator. However, it would have to carry some heavy station-keeping capability to deal with orbital resonance (and even possible collisions) from Phobos and Deimos, which are much closer to Mars than the Moon is to Earth.

You're also assuming that it would be cheaper to build and maintain such an infrastructure on an alien planet than it would to simply extract rocket fuel from ISRU.

Edited October 14, 2014 by Nibb31

[Nikolai]

Molecular weight is not density

For a gas, it's close enough. A given volume of gas, at a given temperature and pressure, will have a mass pretty close to exactly proportional to its molecular weight.

[Acemcbean]

Because it's there.

This was possibly the best reason for why we do Mars-y stuff in this entire thread (so far). And I'm being serious here: Its a pretty damn good reason

[*Aqua*]

The oceans are there, the deserts are there, the antarktis is there. Why won't people colonize them?

Hint: Not because they're there.

"Because it's there" is a (bing translator) "dead shock argument"... eh... this translation seems wrong... it's a thought-terminating cliché (wikipedia). It's not an argument.

[SargeRho]

All of those are still on Earth, and will do exactly nothing if your goal is to preserve Humanity from civilization or even species-ending events.

[*Aqua*]

Do you really believe a Mars colony will survive on its own? It will depend on Earth at least several millenia. And even after that time it will probably have so close (economical and social) ties to Earth that it will collapse when Earth is lost.

Imagine the state of mind of common Mars people when they hear, that Earth is death.

Edited October 14, 2014 by *Aqua*

[SargeRho]

Yes, a Mars colony Will survive on its own once it's self sustaining. While that may well take decades, "Millenia" is absolutely ridiculous.

*cough*

Edited October 14, 2014 by SargeRho

[*Aqua*]

What does a settlement need to survive?

- Defense against all kinds of disaster (meteroids, diseases, radiation, etc.). Sufficent amount have to be build up before Earth goes down.

- Ability to produce enough food. Obviously.

- Ability to produce any kind of maschinery to replace brocken one. This will be difficult. Even today all countries in the world could no survive without importing goods. For example my country produces CPUs but it doesn't produce HDDs. There needs to be factories for everything(!) ready to use. Don't underestimate the numbers here!

- Sufficent amount of ressources to cover all needs for a great time span (at least a thousend years imo).

- Ability to improve all that to expand and recover. Stagnation eventually leads to collapse.

Do you agree?

What does humankind need to survive?

- Sufficent population to ensure genetic variation. This means 80 - 180 people according to this source if they restrict themselves to very strict rules for generations. I don't think this will work so more people are needed. Let's say 20.000 to allow free partner choise in almost all cases. (Marrying cousins will probably be forbidden.)

- Knowledge. The colonists needs to know almost everything people from Earth knew to ensure reparing and replacing of all the stuff they'll have.

- Control. There will be a lot of colonists who lost relatives and just the knowledge of a lost Earth will have a huge impact in people. So somehow public order must be under control to ensure people will go to work instead of killing themselves or drowning in depressions. (= armys of soldiers or psychologists are needed)

- Numbers. As explained the colony need to have a lot of factories, etc. to survive. There need to be enough workforce and experts of all kinds to keep all that running.

My conclusion is a self-sufficent colony must be huge. It needs a lot of time to build all that, I guess at least several hundred years. If you think about it, that isn't possible even on Earth at the moment.

Edited October 14, 2014 by *Aqua*

[Hannu]

All of those are still on Earth, and will do exactly nothing if your goal is to preserve Humanity from civilization or even species-ending events.

It is difficulty to imagine such an event that makes Earth worse than Mars. Asteroid impacts or huge volcanic processes are dangerous because they change climate to somewhat colder to quite short period (geologically) and it prevents agriculture. In Earth we talk about variations couple of degrees in temperature or less than a percent in gas concentrations, if we discuss about cosmic or geologic climate catastrophes. It is negligible problem compared to terraforming of Mars. If we really had a way to change Mars's atmosphere and climate to better for humans it would surely be very much cheaper, easier and faster to restore Earths atmosphere and climate after whatever event.

[-Velocity-]

Mars' geostationary (or "areostationary") orbit is 17000km, which is only marginally easier than the 36000km orbit required for an Earth space elevator.

Incorrect. You're ignoring that Mars surface gravity is only 1/3 that of Earth, and of course that drops off quickly with distance- relative to the surface, its gravity falls off even faster than Earth's. This makes it VASTLY easier to build a space elevator there, as it hugely reduces the required cable tensile strength. In fact, the Wikipedia article on space elevators even claims that it is possible to build a space elevator on Mars (and the Moon, I might add) with currently available materials. While I don't know if this assertion is correct, it doesn't change the fact that Mars is still a vastly easier place to construct a space elevator than Earth.

Edited October 14, 2014 by |Velocity|

[-Velocity-]

Come to think of it, you don't need to destroy or move Phobos for a Martian space elevator to work. Mars may not have oceans to build a mobile space elevator platform on, but you could instead just put your space elevator on a N-S track just slightly longer than the width of Phobos, and slide the cable out of the way when a collision would be otherwise imminent. This would cause some waves to travel up and down the cable though.

IDEA!

Your track does not have to be the full width of Phobos. If you excite a properly-timed transverse standing wave, you can have Phobos fly through a peak or valley of the standing wave. Furthermore, the speed of a transverse wave passing down a tether is proportional to the tension on that tether, so if you spool out or reel in space elevator cable, that will increase or decrease the tension on the cable. This will affect where the peaks are of the various standing wave modes, giving you the ability to vertically position the desired Phobos pass-through points.

The reason you want a standing wave is because they are resonant modes and that resonance is what allows you to use a track much shorter than the width of Phobos.

Edited October 14, 2014 by |Velocity|

[Nibb31]

You still need to build the massive power station and the infrastructure to produce the materials for the elevator on an alien planet. It's a massive task that requires a massive infrastructure. The inconvenience and complexity of building something like that on Mars outweighs any benefit compared to other launch methods.

And you don't address the problem of Phobos and Deimos crossing your path above and below the elevator station. They don't even need to collide, the gravitational pull alone will push your station out of orbit.

[-Velocity-]

You still need to build the massive power station and the infrastructure to produce the materials for the elevator on an alien planet. It's a massive task that requires a massive infrastructure. The inconvenience and complexity of building something like that on Mars outweighs any benefit compared to other launch methods.

I am talking about a hypothetical future where we already have a large presence- probably one or several permanent colonies and thousands (or millions) of people on Mars. Then building it on Mars isn't bad. Otherwise, yes, a Martian space elevator would probably be premature, but you don't actually have to build the cable on Mars, only the ground station really needs to be built on the surface.

And you don't address the problem of Phobos and Deimos crossing your path above and below the elevator station. They don't even need to collide, the gravitational pull alone will push your station out of orbit.

LOL no. You obviously don't realize how miniscule the gravity of Phobos and Deimos are. It sounds like you also don't understand the physics of how a space elevator works. A space elevator is not in orbit.

Edited October 14, 2014 by |Velocity|

[*Aqua*]

You obviously don't realize how miniscule the gravity of Phobos and Deimos are.

It is miniscule yes. The lift won't fall down over night but the stress will accumulate and one day it will rip apart. I guess it will take a few years.

A space elevator is not in orbit.

It's not? Then what keeps it in place?

[-Velocity-]

It is miniscule yes. The lift won't fall down over night but the stress will accumulate and one day it will rip apart. I guess it will take a few years.

The stress will "build up"? That doesn't make any sense. Where?

It's not? Then what keeps it in place?

Centrifugal force, balanced by tension in the tether, keeps it in place. Go attach a ball to a string. Twirl the ball around your head in a circular motion. What keeps the ball in place? Hint: It's not orbiting in your gravitational field. (Umm... well, hopefully not )

What happens is centrifugal force wants to pull the ball away from the center of rotation. If the ball is displaced so that the string does not point towards the center of rotation, then the ball will experience a restoring force that forces it back to the correct position. That is why worrying about the gravity of Phobos and Deimos "destabilizing" the elevator is nonsensical, because a space elevator is a naturally stable mechanical system. (A stable system is a system that, when disturbed from its equilibrium position, experiences a restoring force that brings it back towards its equilibrium position.)

You don't even need a weight on the end of the string- you can twirl a rope around you in a circle without having to attach a weight to the end of it, can you not? The weight of the cable itself can be used as the end mass- but you have to use a longer cable than if you had put a big heavy mass on the end.

A more complete model of the space elevator on human scale would be to attach a string to a spinning bowling ball. The bowling ball is the planet. Attach a weight at the end of the string- that's the space elevator's end station. Now, apply an opposite static charge to the bowling ball and to the end weight to simulate gravity. There will be a distance at which the attractive electrostatic force between the bowling ball and the end weight exactly balances the outward centrifugal force. That corresponds to the geostationary altitude. Thus, your string must be LONGER than this length so that the centrifugal force is greater than the attractive force, and tension is kept on the cable.

The above model still lacks the simulation of the mass of the cable, but you get the drift.

Edited October 14, 2014 by |Velocity|

[peadar1987]

That was assuming an average temperature of -40C, assumes even temperature distribution - the rate of loss when its warmer will not be compensated by the reduced rate when it is colder, and of course, ignores the solar wind - which admittedly is hard to model. It also assumes the gas is never significantly disassociated into smaller compounds.

Anyway... it lacks nitrogen now... where do you propose getting enough to rebuild Mar's atmosphere?

-Although you could stubstitute Argon/Krypton/Xenon for a lot of N2, to truly terraform, it needs to have a N2 atmosphere so that life can fix nitrogen.

It is, as far as I can tell, a conservative estimate, using the figures for perihelion and the equilibrium blackbody temperature there (people forget how cold most of the earth's atmosphere actually is, it's far colder than the average surface temperature).

Current models actually suggest that the solar wind is not the dominant factor in atmosphere loss, thermal diffusion is thought to be the main driver. Obviously, models aren't perfect, however.

We don't know if Mars has significant amounts of nitrogen, there are theories that it is fixed in large deposits of ammonia. If that is not true, the best source would probably be to redirect an asteroid with a significant ammonia content onto a collision course with Mars, but that's something for the far future. Just now, all I'm talking about is Mars' ability to hold an atmosphere, wherever it may have come from.

[Error404brain]

Because it's easy to live on a planet. I mean, we, as humans, obviously need to expand to the solar system. And mars is the easiest to colonize.

1) planet with athmosphere. U don't have to care about gravity or meteorites. That's great.

2) Near of the earth

3) digging hole is easy. Transform an asteroid into a spacestation is hard and we don't know how to do so.

4) low gravity and reasonnable dv to orbit. we can use it as a base for to explore the universe.

Moon is harsh with plants and venus is hell. Asteroid would need way better knowledge of space things (terraforming an asteroid is HARD) and of others asteroid.

We are goin to mars not because it's hard, but because it's easy