Original URL: http://www.theregister.co.uk/2010/11/15/mars_one_way_trips/

How to make boots on Mars affordable - One way trips

Space Cowboys oldster-pioneers to live in cave habitats

By Lewis Page

Posted in Science, 15th November 2010 14:04 GMT

One of the main limiting factors on a manned mission to Mars is the fact that, under normal assumptions, much of the stuff that travelled to the red planet would not be concerned with exploration but rather with bringing the crew back to Earth.

The solution? According to two scientists, it would make more sense for the first humans to set foot on Mars to stay there for the rest of their lives. Not only would this make the mission much cheaper and simpler - it would also, in time, ensure the human race's survival in the event of a disaster befalling planet Earth.

The argument is set out in a paper titled To Boldly Go by extraterrestrial water expert Dirk Schulze-Makuch and physicist/astrobiologist Paul Davies. The two boffins write:

We are a vulnerable species living in a part of the galaxy where cosmic events such as major asteroid and comet impacts and supernova explosions pose a significant threat to life on Earth, especially to human life ... Thus, the colonisation of other worlds is a must if the human species is to survive for the long term.

Schulze-Makuch and Davies say that a normal-type Mars mission with astronauts returning to Earth at the end would cost "an order of magnitude" more than the Apollo programme which put boots on the Moon, and thus it won't happen for a long time, if at all. But they think that the cost would be slashed "arguably by about 80 percent" for a one-way trip, suggesting a cost of only twice Apollo (one may note that NASA's funding has been cut substantially since Apollo finished).

Apart from cost, the scientists argue that a one-way Mars voyage would actually be better for the astronauts. Flight to the red planet using present-day chemical rockets means six months coasting through the interplanetary void. But beyond Earth's protective magnetosphere and atmosphere, space is a hell of dangerous radiation - and a ship or capsule of reasonable mass could offer its crew little in the way of shielding. Six months' radiation dose would be quite enough, according to Schulze-Makuch and Davies: it would be nothing short of cruel to make explorers cop another massive dose on the return trip - not to mention the fact that a year of zero-G and an indeterminate spell in low Martian gravity would make the return to Earth a painful ordeal requiring lengthy rehabilitation.

Unfortunately, Mars doesn't have a useful magnetosphere, and its atmosphere is so thin that it offers very little protection. But according to the two scientists there are plenty of useful caves there, inside which the early Martian colonials would find a radiation-safe environment. There ought to be some caves full of ice, too, which would be excellent as this would furnish not only water for drinking, irrigation of hydroponic crops etc, but also oxygen for breathing. According to To Boldly Go:

The first human contingent would rely heavily on resources that can be produced from Mars such as water, nutrients, and shelter (such as in form of lava tube caves). They also would be continuously resupplied from Earth with necessities that could not be produced from the resources available on Mars. This semi-autonomous phase might last for decades, perhaps even centuries before the size and sophistication of the Mars colony enabled it to be self-sustaining.

Schulze-Makuch and Davies admit that "considerations may be raised" against their idea to the effect that nobody would volunteer to go, or anyway nobody sufficiently sane and capable to do the job. But they say that's not true:

Informal surveys conducted after lectures and conference presentations on our proposal have repeatedly shown that many people are willing to volunteer for a one-way mission.

"Colonists may be preferred who are beyond their reproductive age"

As for the loneliness and psychological pressures of being a Martian pioneer, the two men argue that humans have often made one-way voyages that would have seemed to them every bit as isolating as one to Mars would seem to us. Indeed the colonists of old would actually have felt far more cut off from their homelands than a Martian settler/explorer able to contact Earth by radio.

It is important to realise that this is not a 'suicide mission' ... The situation these first Martian settlers are in, who would of course be volunteers, would really be little different from the first white settlers of the North American continent, who left Europe with little expectation of return.

The astronauts will have undergone psychological profiling and training before embarking on the mission, and would remain in constant contact with Earth via normal channels such as email, radio and video links. In the era of modern communications they would in fact feel more connected to home than the early Antarctic explorers (who had no systematic psychological training either). Over time, the human contingent on Mars would slowly increase with follow-up missions.

The Martian pioneer settlements would be based around underground ice-cave habitats, with hydroponic crops grown on the surface in domes to provide food and extra oxygen. Solar power would probably not be sufficient so far from the Sun, so each "cave-based biosphere" would need a small nuclear reactor. Fuel or replacement reactors would need to be shipped out from Earth, but fortunately nuclear fuels are tremendously energy-dense and this would not be a major pain like hauling rocket fuel would be.

The scientists don't think it would be a good idea for the colonists to raise children on Mars, or anyway not to start with. The radiation dose suffered on the space voyage and the absence of proper medical care on Mars would damage the astronauts' reproductive organs and reduce their life expectancy to 20 years or so. Thus "initially, colonists may be preferred who are beyond their reproductive age".

The elimination of return trips would, however, make it comparatively affordable to keep sending more people, though, and in time there might be a viable human gene pool on Mars allowing "the possibility of a successful long-term reproduction programme".

One objection foreseen by Schulze-Makuch and Davies is that humans and their imported biosphere might wipe out any native life to be found on Mars. But they say that firstly that train has already left the station as "several unsterilised, or inadequately sterilised, spacecraft have already been sent to Mars". Also, despite a lot of searching, nobody has managed to actually find any life on the red planet - and quite bluntly in any case concern over possible Martian microbes shouldn't prevent the human race acquiring its survival insurance policy.

In conclusion, the two scientists suggest that the Mars colonisation effort should begin with survey missions to identify a suitable ice cave, then unmanned flights to deliver the first base and get it mostly set up robotically before even launching any humans.

All this done, Schulze-Makuch and Davies propose that four astronauts be sent out in two two-person one-way craft, with this approach offering some redundancy and the possibility of rescue by the other ship in the event of disaster. Once there actually are people on Mars, the scientists argue, not the least of the benefits would be the fact that governments would probably feel unable to subsequently axe the programme as happened with Apollo, or even worse, give up on space altogether. Supply flights would have to continue at least until the astronauts had died.

The boffins write:

The strategy of one-way missions brings this goal within technological and financial feasibility. Nevertheless, to attain it would require not only major international cooperation, but a return to the exploration spirit and risk-taking ethos of the great period of Earth exploration, from Columbus to Amundsen, but which has nowadays being replaced with a culture of safety and political correctness.

They admit, however, that the financial and political challenges facing their plan are "monumental".

To Boldly Go is published by the Journal of Cosmology, and can be read in full here. ®