[thedoc (OP)]

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


                                        Visit the webpage for the podcast in which this question is answered.

[chapter podcast=1001045 track=15.05.19/Naked_Scientists_Show_15.05.19_1003652.mp3]  ...or Listen to the Answer[/chapter] or [download as MP3]

[Emc2]

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..

http://articles.nydailynews.com/2012-06-01/news/31965738_1_mars-one-manned-mission-planetary-rover

http://english.ruvr.ru/2011/08/18/54840375.html

http://www.marstravel.org/2011/08/why-nasas-manned-mission-to-mars-will.html

http://en.wikipedia.org/wiki/Manned_mission_to_Mars

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.[53][54] 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.[53][54]

[CliffordK]

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.

[Rgclark]

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

  Bob Clark

[damocles]

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.

[CliffordK]

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

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.

[syhprum]

As soon as simple cold fusion power plants and gravity shields are available.

[CliffordK]

As soon as simple cold fusion power plants and gravity shields are available.

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]

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.

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.

[damocles]

From CliffordK:

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.

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]

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 []