Science Questions

Could humanity colonise Mars?

Mon, 18th May 2015

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Mark Pawelek asked:

Given our current technological level, is it possible for us to colonise Mars? If so, how? If not, what are the major barriers?


We put this question to Richard Hollingham, and he had this to say: Mars rocks

Richard - Yes, is the short answer.

Kat - Yay! Letís all go.

Chris - One of the barriers must be about 237 million kilometres.

Richard - Yeah, 225 million kilometres away average.

Chris - Yes, itís even closer sometimes.

Richard - Yeah, it is closer sometimes. So, there are lots of things you have to do and the technology is there to do the things to get there at least. We would probably want to assemble a spacecraft in orbit. There's no spacecraft currently capable of getting there. They need to fly to Mars. Thatís going to take at least 6 months, if you time everything right. You will need a spacecraft you can move around in and you can exercise in because it would be quite funny in a way if they land on Mars, they get out and they all fall over because they can't walk anymore, because their bones are not strong enough. So, you get there and you land. Thatís all doable. Thatís been done with the robots.

Kat - Thatís just an engineering problem.

Richard - Thatís an engineering problem. We can do that. Itís been a bit hit and miss, but the last few missions have all been successful - we have got to Mars. Survival is an interesting one. Now, you could survive in the same way that astronauts survive on the International Space Station.

Kat - So just like in a pod and just kind of staying in there?

Richard - Yeah, you could be in a fairly large-ish area. You could maybe have an inflatable base or something like that, and rely on constant supplies from Earth. So, every few months, send another rocket off, it lands, they've got supplies for another few months. They could try growing things, so hydroponics or maybe even use Martian soil to grow things. In theory, that works. Itís a bit hit and miss. Things have been grown but in the Earthís atmosphere very successfully in Antarctica. You can create an artificial soil. They know that works. Space station experiments have been a bit hit and miss. The Mars Society have a base in Utah and theyíve been doing a lot of this stuff. You ask them about whether the food was edible, they said they "grew a lot of interesting things but none of them were edibleĒ. So, thatís an issue. So, you can get there, you can probably survive I would say, and actually, in a few more years, weíll probably be there. The big issue is coming back, because NASA have not yet managed to even get a canister-sized, a coffee cup-sized, capsule of Martian material back to Earth successfully.

Kat - I'm getting the feeling this would be a one-way trip.

Richard - Well, thatís what Mars One are proposing, the Dutch organisation. Their funding is a little up in the air at the moment, but they're serious people and thatís what they propose Ė a one way trip to Mars. So, you go to Mars, live out the rest of your life and you die.

Chris - The radiation's a big issue though, isnít it? Because we saw on the Curiosity Mission they actually used the radiation sensor on the Curiosity rover during its 9-month trip to Mars. It logged a radiation dose of about 2/3 of what NASA considered to be safe lifetime working dose of radiation just on that one journey. And then there was another paper out just recently, Charles Limoli from the States published his paper, where they exposed mice to the sorts of high energy cosmic particles that you would encounter in space once you escape from the Earthís protective envelope of our magnetic field. These mice all got changes in their brains. It looked like someone had come along and sort of pruned the hedge because all of the nerve cells had fewer connections.

Kat - As a geneticist, I find this interesting because if the idea is, you'd send people to Mars and they would get busy and make new people on Mars. If theyíve actually been exposed to a lot of radiation, that could make some fundamental changes in the DNA of their eggs and sperm, and then maybe sort of super evolution. Very interesting things to think about!

Richard - Well, I mean there are other issues there. In terms of population size, you need thousands of people to prevent genetic defects, prevent cousins breeding with cousins...

Chris - Yeah, because otherwise you're recreating the Egyptian dynasty, aren't you,  sort of when brothers and sisters married each other.

Richard - Exactly, youíve got problems to start with. Once you're on Mars, a lot of the concept bases are actually underground. So, they eliminate the problems of radiation on Mars. I think the problem of getting to Mars, thatís probably surmountable. They're looking at new shielding techniques, probably using water, something like that within the spacecraft. So, thatís probably okay. I mean, my fundamental problem with this, why would you want to go to Mars?! Mars is bleak, cold, barren. You can't evenÖ

Kat - I mean, you could just go to Newmarket.

Richard - Itís a horrible, horrible place. I wouldnít recommend it. Of places to go, I donít think itís a very interesting place. I think what will be more interesting is some sort of colony in space.

Chris - But to be fair, when the first settlers arrived in Australia and landed in what is now Sydney, they said, ďThis is a horrible place. We donít want to be here.Ē Now, itís one of the worldís most beautiful cities.

Richard - Yes, because there's air to breathe.

Chris - Just think about what Mars could be.

Richard - Even Chris, even in Australia there is air to breathe! There is not air to breathe on Mars.

Kat - Leaving that there with us, I'm sure there's so much we could talk about.

Chris - There's a missed joke opportunity there because of course, they were going to make a nightclub on the moon  but then someone said no atmosphere!


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The technology is here, and is currently being tested by some groups for a near future launch to put a small "colony" on Mars.

  It is going to happen sooner then most think..

NASA/SpaceX 'Red Dragon' (2012)
Main article: Red Dragon (spacecraft)

Red Dragon is a proposed concept for a low-cost Mars lander mission that would utilize a SpaceX Falcon Heavy launch vehicle, and a modified Dragon capsule to enter the Martian atmosphere. The concept will be proposed for funding in 2012/2013 as a NASA Discovery mission, for launch in 2018. The primary objective would be the search for evidence of life on Mars (biosignatures), past or present; a substantially unmodified version of the crewed Dragon capsule could be used for payload transport to Mars, and would be a precursor to the ambitious long-term plans of a manned mission to Mars.
Emc2, Wed, 22nd Aug 2012

Undoubtedly we will colonize Mars, perhaps sometime this century, or early next century.

I think we should colonize the moon first, and them Mars second.  Mars may have more accessible water and other resources than the moon.  But, both of them would require pressurized habitats and a self contained colony, and likely cosmic ray shielding. 

I find it doubtful that Mars (or the moon) will ever support a dense atmosphere like Earth. CliffordK, Wed, 22nd Aug 2012

Elon Musk "Mars Pioneer Award" Acceptance Speech - 15th Annual International Mars Society Convention.

  Bob Clark Rgclark, Mon, 27th Aug 2012

I am an extreme sceptic on this one. We have been used to operating on Earth with a large reserve of chemical energy immediately available. If we try to colonize Mars, the only energy sources immediately available to us will be those we have imported. There will be an urgent need to get food crops started (for sustenance and bodily energy requirements) and forests (to enrich the atmosphere with oxygen, both for breathing and for any possible exploitation of biofuels as chemical energy. It is almost certain that we would not be able to afford the initial energy cost of such an enterprise.

It would be vitally necessary to exploit solar energy, but solar energy fluxes on Mars will only be around one third of what they are on Earth (inverse square law), and on Earth we have only managed to make solar energy meet about 10% of our total consumption.

Mars does not have an ozone layer. Ultraviolet components of sunlight that can rapidly and irreparably damage living things will need to be shielded out. Food crops and forests will need to be shielded with huge transparent domes, made of a material that will shield out UV light but transmit visible light, and that will not degrade or darken under intense UV radiation. Although the UV radiation reaching Mars will only be around one third of that reaching Earth, our ozone layer reduces the intensity of this radiation reaching the surface by roughly a factor of ten million. The technology of Mars colonization is barely feasible in many parts, and almost certainly prohibitively expensive. It would be far superior, less expensive in both monetary and energy terms, and more desirable to use similar, better developed technologies and apply our resources to learning to live sustainably on Earth. It is no co-incidence that at the time of Neil Armstrong's death, no human being had set foot on the moon in nearly forty years.

damocles, Mon, 27th Aug 2012

Thanks for the link, although it was a bit long winded.
Elon Musk does have quite a vision. 

Half a million bucks for a trip to Mars sounds a bit optimistic.  But, perhaps....  sometime. 

Mr. Musk talked about "reusable rockets".  Perhaps one option would be to conduct a two part trip.  Rockets to achieve orbit, and a larger, shuttle between the planets. CliffordK, Mon, 27th Aug 2012

As soon as simple cold fusion power plants and gravity shields are available. syhprum, Mon, 27th Aug 2012

You mean when pigs fly?

There may not in fact be any economic reasons to colonize Mars.  And, thus it may be in the domain of visionary entrepreneurs such as Space-X.

However, I do believe that there will be many economic and scientific reasons to colonize our moon.  The big question I have is whether we would be able to ever support two-way commerce between Earth and the moon, or between Earth and Mars once the colonies are established.  Eventually the colonies would become fairly independent from Earth.  Yet, producing satellites and space ships on the moon might be very important for Earth.  I would not imagine that Earth would be sending too many watermelons to the moon, once agriculture is established there.  Perhaps gold for computer manufacturing, or microchips that couldn't be produced locally.

But Mars? CliffordK, Mon, 27th Aug 2012

We certainly have UV shielding glass and plastics.  It is used in many greenhouses here on Earth, but perhaps it is not as good as you are suggesting would be required.  There is also the need to shield from cosmic rays.

I find it doubtful that Mars could support an O2 atmosphere due to the lower gravity.  But, what about a thin O3 atmosphere?  Or, at least filling all multi-paned windows with O3.

One would either need to transport dry ice from the poles to the equator, or condense the CO2 out of the atmosphere for the trees and plant matter to build an atmosphere within the domes. CliffordK, Mon, 27th Aug 2012

From CliffordK:

An ozone layer is a dynamic phenomenon. It is not possible simply to have ozone passively absorbing UV light. It is part of a complicated reaction system:

(1) O2 + light (wavelength<220 nm) --> O + O

(2) O + O2 + M --> O3 + M

(3) O3 + light (wavelength= 220-310 nm) --> O2 + O

(4) O + O3 --> 2 O2

(5) O + O3 + catalyst --> 2 O2 + catalyst

(6) O3 + surface --> surface-O + O2

When ozone absorbs a photon of UV light, an ozone molecule is destroyed according to reaction (3) above.
It can be replenished in a three-body collision, reaction (2). Reactions (2) and (3) conserve "odd oxygen", that is, O + O3, and form a subsystem of the overall reaction scheme in the Earth's stratosphere.

Reactions (4) and (5) destroy "odd oxygen". Chlorine compounds and oxides of nitrogen are the most important catalysts for reaction (5) in the Earth's stratosphere. Reaction (6) can be significant when volcanic dust enters the stratosphere, but would certainly be a consideration if ozone-filled double glazing were proposed.

And, of course, reaction (1) shields the even more damaging high energy UV radiation in the mesosphere and the thermosphere, and is the main source reaction for odd oxygen.

The bottom line, as far as I can see, is that the presence of a useful amount of ozone on a planet requires an atmosphere that is at least 1% oxygen, and at least 1 kPa pressure. I do not think that ozone double-glazing or similar schemes are a possibility. Ozone is too reactive and too toxic for any attempt to produce it directly inside the domes, for example, damocles, Mon, 27th Aug 2012

Incidentally, for anyone who wants to read up on martian atmospheric chemistry there is an excellent (but perhaps inaccessible to a lay readership) summary in R.P. Wayne, "Chemistry of Atmospheres", Oxford UP.

Yes, apologies to this website, but Wayne is an Oxford man damocles, Mon, 27th Aug 2012

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