moon VS mars

[ravener]

what is the reasons for going to mars?

human spaceflight as we all know is hard, but most of us want us to spread our wings and become a multi body sosciety. what then differs between mars and the moon and in which cases would they be more suited than the other for colonization?

the upsides of mars includes the abundance of important resources like water, methane and CO2. mars also has an atmosphere that allows for these to stay frozen without any serious problems.

however there are also downsides, one of there being the prohibitively long transit times that will require ISS sized ships to accomodate any large ish amount of people, and that's just counting internals for storing food, water, purification/recyceling equipment, living quarters/ bunks, large scale CO2 scrubbers and everything else needed to sustain life.

the moon is an alltogether different story. life on the moon is harsh, there is little in terms of resources to be had. you could make some interresting materials due to the vaccum, but nothing really that amazing. there is some water ice to be had, but nothing compared to mars. the little ice there is though, if we can get it, is very valuable. and there the great positive of colonizing the moon comes into play. getting there is doable, if not trivial compared to mars. yes we can reliably get to mars now, but the transit times to the moon is so short that a few blokes could just sit it out in a tin can. the infrastructure to live on the moon is much the same as that of mars, with one exception; landing and taking off on the moon compared to mars is trivially easy, with modern engines you could probbably do a SSTO and on the same tank of fuel land again

in short the moon is great as an orbital fuel station to be used as a springboard to the solar system in adittion to gaining some experience in colonization. if we can colonize the moon we can probbably colonize mars.

mars is something for the future where sustaining our fragile bodies no longer is a problem.

this is just my bitcoin on this debate

sorry if my english sucks a bit, i'm tired.

[Tux]

So my view fall into three categories.

1. its ridiculously more efficient now to get the science we need using robotics and probes. So if we want to learn something that is going to be the best way by far.

2. If we want access to resources in space its still more efficient to have robotics bring those resources back.

3. All though earth has environmental problems its still (and likely forever) the most habitable planet in the solar system.

I say robots!

[metaphor]

While the Moon is a nice target in itself, it's not really on the path to Mars.

The Moon and Mars have very different environments. Mars is in many ways like an average of the Earth and the Moon. So if you want to test Mars-bound spacecraft elements, it would be orders of magnitude cheaper to just test them on the Earth rather than the Moon.

The reason why a Moon mission could be relatively cheap is because it takes a very short time, a few days up to a couple of weeks. A Mars mission has to be much longer and that's why it needs many other spacecraft elements like a transit habitat and a surface habitat. But a long Moon mission, like a permanently staffed Moon base, would do away with that advantage and become probably just as expensive as a long Mars mission.

Look at the energy required to land something on the Moon vs landing the same payload on Mars. For the Moon, you need about 3.2 km/s for TLI, 1 km/s for LOI and 2 km/s for landing. Assuming LOI and landing are done with hypergolics, that means that if you wanted to land a 50-ton habitat on the Moon, you would need to bring about 300 tons to LEO. For Mars, you need about 3.6 km/s for TMI, a heat shield to aerobrake at Mars, and about 1 km/s for landing. So to land a 50-ton habitat on Mars, you would need to bring about 250 tons to LEO. So it's not really cheaper to get something to the Moon than to get it to Mars.

Returning from the Moon is much easier than returning from Mars, but Mars has the advantage of being able to make the ascent propellant through ISRU relatively easily.

The Moon does have the advantage that it's closer, so that means it's safer with more abort possibilities. But lunar habitats need to be more complex in order to survive the harsher conditions on the Moon, and possibly more supplies needed since less can be made through ISRU (water, O2). The Moon might have some water deposits, but only in specific places at the poles and it's not really know if they actually exist. Mars is known to have subsurface ice almost everywhere on the entire surface, as well as an atmosphere available from anywhere on Mars (CO2 can be made into propellant and oxygen).

So it's not really clear that having a crewed Moon base would be cheaper than a Mars base. On top of that, humans don't bring as much to the table on the Moon as they do on Mars. A robotic lunar base might be cost-efficient, and can be operated from Earth because of the very small light lag, but the same can't be done on Mars, so humans actually being there and making real-time decisions brings a lot more to the table in terms of science and exploration potential.

[Javster]

Your bitcoin? You know Good Mythical Morning?

On topic, with the current state of the world, even a landing would encourage people to support a permanent base.

[rtxoff]

One reason would be:

Chance for someone to step out of that space ship and before step onto the mars soil say something like "a small step for a man a giant leap for mankind" while whole mankind sits in front of their media consuming devices getting the heebie-jeebies.

[NFUN]

One reason would be:

Chance for someone to step out of that space ship and before step onto the mars soil say something like "a small step for a man a giant leap for mankind" while whole mankind sits in front of their media consuming devices getting the heebie-jeebies.

I'd have to imagine the first person to step on the soil will have spent most of the 6 month journey thinking of a quote.

[SargeRho]

Mars: Has an atmosphere, terraforming potential, all the elements needed to sustain a colony, partial radiation and small meteorite shielding thanks to the atmosphere.

Moon: No atmosphere, full radiation exposure, dead wasteland, good for ressources used in space, radio telescopes on the far side, but that's it.

[Mitchz95]

If we truly want to become a multi-planet civilization, we need to be able to set up self-sustaining colonies on other worlds. I can see that happening on Mars, but not the Moon.

[running]

That's the ultimate goal, a fully selfsustaining colony outside of earth.

So if something bad happens on earth, we as a species would survive. Possibly even recolonize earth at some point.

But.... we don't even have something like that on earth itself. Even the most isolated tribes of indians in the amazonian jungle are still in possesion of items that came from outside.

If there would be no more incomming supply runs from earth, any base you'd be able to build in our life time would at some point fall apart.

Mars has the most gravity. 38% of what we are used to as compared to the 17% on the moon. Now if you are not planning to ever visit earth again, either one might be fine though.

With only 17% strapping some pieces of cardboard to your arms might allow you to fly inside a habitat dome.

[Mitchz95]

Would it be possible to set up a centrifuge wheel on or beneath the surface that could simulate Earth-like gravity? That would be very useful for people working at the base.

[mdatspace]

The moon does not help us prepare for mars. Mars does not have similar surface conditions. A moon mission will not help with technology needed to go to mars due to this. I would support a robotic moon base, but not a human one.

[the_bT]

The moon does not help us prepare for mars. Mars does not have similar surface conditions. A moon mission will not help with technology needed to go to mars due to this. I would support a robotic moon base, but not a human one.

I see a lot of these "set up a base here or there" type discussions lately... I always wonder about one thing:

If you want to support a large group (more then a half dozen) people outside of LEO you need some sort of biosphere module where food is grown don't you?

Now has anyone ever even tried to make something like this? A room with a bunch of plants that produce food (a lot) and exist in complete isolation. No water goes in, no oxygen or CO2 in or out. Nothing.

That seems sufficiently hard a challenge to me. That is technology needed to colonize any body I would say. And it can be developed without going to space at all.

Given that hunger is one of the biggest problems in today's world, whatever is learned in that endeavor is also more likely to benefit humanity then a second landing on the moon or a human on mars.

[jwenting]

The best reason to go Mars is the age old reason for human exploration: IT'S THERE.

There's no other reason needed to go there, really.

[Nibb31]

I think many people are misguided when they think of Mars being more inhospitable than the Moon. I think they are misled by the fact that pictures of Mars look a lot more familiar, like some deserts on Earth. Those pictures don't convey the harshness of environment, the cold, the radiation, the lack of atmospheric pressure.

In fact, on a scale that goes from habitable to uninhabitable, both the Moon and Mars are pretty close to each other at the very hostile end.

Now, picking a destination

First of all, let's rule out "colonies". To be sustainable, a colony would need to have hundreds of people. That's hundreds of mouths to feed, to house, and for which you need to provide closed loop life support. It simply is not possible with current technology to send that much infrastructure (or the infrastructure to build that infrastructure). It's a dream that is centuries away in the future. I'd also suspect that it's a sort of romantic science fiction dream as a way to relive US history (a sort of new Wild West founded by space homesteaders...). However, that is ethnocentric, and reflects different times and whole different reality.

It also doesn't make sense, because if you can colonize and survive in a sterile wasteland like Mars, then we have no reason to go to Mars. We could build the same colonies anywhere on Earth or in LEO for much less risk and much less energy.

So with colonies out of the way, what we are looking at is something ranging from a "flags and footprints" expedition to a semi-permanent science outpost.

For me, a science outpost makes sense as a way to learn about:

- closed loop life support

- off world logistics

- building and maintaining infrastructure

- partial gravity and radiation studies

- biological studies

It would have to work as sort of ISS or like the Amundsen-Scott base in Antarctica: it would have to rely on frequent supply flights and crew rotations from Earth with a goal of decreasing the reliance on those logistics as science progresses and additional capabilities are added to the outpost. It would only support a small number of astronauts at first, from 4 to maybe 10. So whether we go the Moon or to Mars, if we want anything more than "flags and footprints" we will first need to build the logistics to support a long duration outpost.

This is why I support building a lunar infrastructure. We simply don't have the technology or the resources to support a continuous supply line between Mars and Earth. The launch windows are too infrequent anyway. If we sent humans to Mars, it would be a one-off flags and footprints and then we would be back to square one.

I'm all for setting ambitious goals, but those goals have to be achievable. A one-off expedition might be possible, at a stretch, but I don't think that a semi-permanent outpost on Mars is achievable with current technology and budgets.

Concentrating on the Moon allows us to expand our knowledge, learn how to live on a different planet, and buys us time for developing new propulsion technology which might allow us to expand to other planets in the future.

Edited June 7, 2014 by Nibb31

[jwenting]

Actually, we could have done it with 1970s technology. We didn't, the technology was largely lost, risk aversion took over as legions of lawyers seek to sue anyone and everyone for anything and everything that might possibly go wrong, and we're now no longer able to...

It's technically feasible to create a permanent settlement on either the moon or Mars that's self sustaining, certainly as long as there's no major catastrophes, catastrophes large enough that a similar sized settlement on earth would require outside help.

Problem is that it would be extremely expensive, and very high risk for the initial colonists.

And in the current political and social climate that means it's not going to happen. Instead of expansion and life, humanity has chosen stagnation and eventual death for the species. We've traded ambition for having our beds made for us, living without risk, without any lack of anything whatsoever. And that's the end of the line for the species.

[Aghanim]

A space station at lunar orbit with a base should provide some good development locations

[Nibb31]

Actually, we could have done it with 1970s technology. We didn't, the technology was largely lost, risk aversion took over as legions of lawyers seek to sue anyone and everyone for anything and everything that might possibly go wrong, and we're now no longer able to...

What 70's technology are you talking about? Did we have life an ECLSS that could support a crew for 2 years? Did we have Mars heavy landers? 70's technology was Salyut space stations and Skylab, neither of which had the endurance or the capability to protect their crews against solar flares. Did we have the industrial capability of launching several Saturn Vs in a couple of months to assemble a large MTV? Did we have the industrial capability to do that continuously enough to maintain a semi permanent human presence on Mars or would it have been just flags and footprints again?

The only thing we had in the 70's was Apollo's heritage, namely the Saturn V, but that was entirely geared towards the Moon landings. So what 70's technology are you talking about? Did we have life an ECLSS that could support a crew for 2 years? Did we have Mars heavy landers? 70's technology was Salyut space stations and Skylab, neither of which had the endurance or the capability to protect their crews.

[Skyler4856]

I see a lot of these "set up a base here or there" type discussions lately... I always wonder about one thing:

If you want to support a large group (more then a half dozen) people outside of LEO you need some sort of biosphere module where food is grown don't you?

Now has anyone ever even tried to make something like this? A room with a bunch of plants that produce food (a lot) and exist in complete isolation. No water goes in, no oxygen or CO2 in or out. Nothing.

That seems sufficiently hard a challenge to me. That is technology needed to colonize any body I would say. And it can be developed without going to space at all.

Given that hunger is one of the biggest problems in today's world, whatever is learned in that endeavor is also more likely to benefit humanity then a second landing on the moon or a human on mars.

Interesting fact, Elon musk developed an interest in rocketry after he looked into sending an experimental greenhouse to Mars.

[Nibb31]

I see a lot of these "set up a base here or there" type discussions lately... I always wonder about one thing:

If you want to support a large group (more then a half dozen) people outside of LEO you need some sort of biosphere module where food is grown don't you?

Now has anyone ever even tried to make something like this? A room with a bunch of plants that produce food (a lot) and exist in complete isolation. No water goes in, no oxygen or CO2 in or out. Nothing.

That seems sufficiently hard a challenge to me. That is technology needed to colonize any body I would say. And it can be developed without going to space at all.

Given that hunger is one of the biggest problems in today's world, whatever is learned in that endeavor is also more likely to benefit humanity then a second landing on the moon or a human on mars.

I agree. I don't see the point of trying to build a self-sufficient base on Mars or the Moon if we can't even do it on Earth. A successful "Biosphere"-type of experiment in Antarctica or under the ocean will have to be tested before we think about any long-duration outpost.

[ravener]

if we really wanted we could probbably make a biosphere on earth. the reason to go to the moon is that it is close enough to test out infrastructure for going to mars. if your habs are rugged enough to survive the moon it is probbably rugged enough for mars, in the end the moon is quite a lot harsher than mars.

the reason going to mars isnt up for discussion at the moment is that going there is so hard that it makes no sense. we could probbably build a selfsuficcient colony on the moon with the resources needed to get ten or so people to mars. we have gotten pretty good at recyceling in the last few decades and the little resources available on the moon would probbably be enough to keep us alive. getting a carbon oxygen cycle running isnt that huge a problem when earth is so close, it would be the most important resource to ship to the moon from earth in the startup phases, oxygen can be mined on the moon and a working fusion reactor seems to be on the horizon, so power might not even be a problem on the moon.

basically, we cant really get to mars. and the moon is a little useless. going to the moon is great for getting fuel so mars isnt too huge of a leap compared to fuel availability in orbit.

[Creature]

I'm not always sure if people are talking about self-sufficience as in total independence of supply missions or as in closed-loop life support. The life support is something that's very much doable if enough money and effort is poured on it as it's just a technical matter, even though a complex one. Total independence would mean that they'll build everything in situ. Every machine to run the life support, every machine to build the life support system and every machine to mine the materials for everything plus of course the machines to build those machines et cetera. I don't see that possible without either a very, very long term project or a level of nanotechnology that we're a century away from. In both cases we're talking several decades at least.

[Idobox]

Definitely the Moon.

The moon is close, and doesn't have launch windows, so it will be much easier to build incrementally, and evacuate in case of emergency.

Self-sustaining closed-systems are not a reality yet, but there is a lot of very interesting work going on for habitats that can sustain people for months, which would be a good first step.

Then, we need to find a reason to go to the Moon. Preparing for Mars is nice, but nobody will invest the kind of money required with only this goal.

The Moon has ice, which can be turned into rocket fuel, which can then be sent to LEO. But you can also turn the regolith into Al+Mg and O2, a viable fuel, and we don't have too much use for fuel in LEO right now.

My favorite use for the moon is rocks. If you put a momentum exchange tether in LEO, you can use it to accelerate ships from suborbital to orbital trajectories, making spacelaunch much cheaper. The issue is that the orbit of the tether decays every time you do that. A good way to restore it without sending rocket fuel from the ground (which would make the whole thing less efficient than normal multistage rockets) is to use the tether to slow down stuff to suborbital speeds, stuff like old satellites, manned capsules, or rocks launched from the moon.

To do that, you would need a mass driver on the moon, sending rocks or bags of dust on an intercept trajectory. Because the moon doesn't have an atmosphere, many things that wouldn't work on Earth are possible, from maglevs to stupidly large trebuchets. Rotovators are a seductive option, since there are the same technology as the momentum exchange tether in LEO.

Whatever system you choose to send mass towards earth, it will likely need regular maintenance, a domain where humans are still far superior to telepresence. And since you don't want to have a unoccupied space janitor on the moon, you might as well put a bigger habitat and run some reduced gravity or geology experiments, and maybe even put a telescope or two in a place where the view of Earth is blocked.

[Aghanim]

I agree. I don't see the point of trying to build a self-sufficient base on Mars or the Moon if we can't even do it on Earth. A successful "Biosphere"-type of experiment in Antarctica or under the ocean will have to be tested before we think about any long-duration outpost.

Well let's hope that those experiments are properly managed... Everyone say that Biosphere 2 is a failure: http://www.wired.com/2009/04/biospheresci/ but no, it isn't. It just that something is really wrong:

One of their own scientific consultants came to be critical of the enterprise, too. Dr. Ghillean Prance, director of the Royal Botanical Gardens in Kew, designed the rainforest biome inside the Biosphere. Although he later recanted, acknowledging the unique scope of this experiment and contributed to its success as a consultant, in a 1983 interview (8 years before the start of the experiment), Prance said, "I was attracted to the Institute of Ecotechnics because funds for research were being cut and the institute seemed to have a lot of money which it was willing to spend freely. Along with others, I was ill-used. Their interest in science is not genuine. They seem to have some sort of secret agenda, they seem to be guided by some sort of religious or philosophical system."[44]

Fortunately, now Chinese is building some sort of closed ecological system (?)

[Jacob01]

I'd say go to the Moon first. Although its not that similar to Mars, and the distance between the Earth and the Moon is nowhere near to distance between Earth and Mars, I think it would be a good stepping stone. Just to try and set up a base relatively close to Earth first incase anything goes wrong as kind of a test. Then, once everything has been tested on the Moon and we have a suitable design, go to Mars.

Perhaps we could also build a prototype of a ship suitable to go to Mars in orbit around the Moon, keep the astronauts in Lunar orbit for the amount of time it would take to reach Mars, land them on the Moon and then do the same thing again to simulate the return journey. Although that would be quite an expensive option with little point other than to test the ship. Perhaps the ship could be reusable so we wouldn't have to build another ship for the actual trip to Mars, reducing the cost.

[SargeRho]

But there is basically nothing you can test on the Moon that would be used on Mars, other than a closed loop life support system which you can test on Earth for much cheaper.