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.