Sunday, April 26, 2015

Obstacles blocking colonization of Mars

Getting to Mars
With current rocket technology, it takes between seven and nine months to reach Mars. That’s a long time to be cooped up inside a tiny spacecraft with, presumably, a small number of crewmates.
The potential psychological effects of such isolation are not fully known, although there are parallels here on Earth with long-duration submarine deployments and wintering expeditions in Antarctica.
NASA announces world's biggest-ever rocket to take man to Mars and beyond
Then there are the physical health issues — in weightlessness, your bones and muscles begin to deteriorate. Astronauts aboard the International Space Station take regular exercise, but even that does not fully stop the decline.
And then there’s food. Who wants to spend seven months eating instant meals? Growing some edible plants during the journey sounds like a good idea, but it’s a bit of a risky proposition — what happens if your crops fail?



Landing on the Red Planet
Assuming you reach Mars in one piece and are still sane, you then face the challenge of landing.
Landing on Mars is hard … much harder than landing on Earth or the Moon. Earth has a thick atmosphere, so a solid heat shield and a set of parachutes are all you need. With the Moon, because there’s no atmosphere you can just ride your rocket thruster all the way down to the surface.
But Mars’ with its very thin atmosphere sits awkwardly in the middle. Heat shields can only do so much in thin air, and rocket thrusters are harder to use. For the Curiosity rover landing, NASA resorted to an untried technique called a ‘skycrane’, where a combination of heat shield, parachutes and thrusters were used. But they were right at the limit of what could be done — there’s no guarantee that larger craft, such as sizeable habitation modules, can be landed in quite the same way.

How a landing may possibly take place on Mars

Living off the land
But let’s assume you make it down to the ground in one piece. What then? You can’t breathe the air — Mars’ atmosphere is only 1/100th as thick as Earth’s, and its almost entirely carbon dioxide. So you’re going to have to produce your own oxygen, and stay inside most of the time. Venture out of doors and you’ll need to wear a spacesuit.
With the air being so thin, and because Mars — unlike Earth — doesn’t have a strong magnetic field, there’s no protection against solar and cosmic radiation. So you’ll need to overcome that somehow.
And what about food and water? You’ll have to grow your own food, supplemented by finite supplies brought from Earth. Again, good luck if your crops fail for one reason or another. Water? Well, it is possible to extract oxygen from the carbon dioxide and combine it with hydrogen — perhaps brought with you from Earth — to produce water. But you’ll have to recycle everything, perfectly, otherwise you’ll eventually run out.

Artist's depiction of a Martian settlement

Will it ever happen?
Theoretically, none of these issues are completely insurmountable, given enough time and resources. But no one has tried them out yet — even NASA says it is decades away from being able to mount a Mars expedition.

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