Human Exploration of Mars
For our February 2002 lecture Dr. Julian Hiscox, a microbiologist from Reading University, gave us a talk called "The Human Exploration of Mars". Dr. Hiscox started off the talk with a short history of Mars. He explained that the atmospheric pressure on Mars is too low to allow any liquid water, even on the equator at summer. So, did life exist at some stage on Mars or not? The pendulum has swung from left to right over the years on this question. Percival Lowell thought he saw canals through his telescope, and if anyone wanted to look at Mars through his telescope, they had to agree with him before being able to use it. H. G. Wells "War of the Worlds" also convinced a lot of people there was life on that planet. Marconi using a radio telescope got readings which he thought were indications of life on Mars, but which was actually background radiation. his part of the talk. So, the pendulum swung to the left, there was a good possibility of life on Mars. The unmanned spacecraft, like Mariner and Global Surveyor were sent to Mars. Scientists thought there might be microbial life in the soil but there wasn't. Not even traces of the basic background level gases on the surface of Mars, which make up the building blocks of life. So the pendulum has now swung to the right.
We now know that about four million years ago there was abundant water on Mars. Mars was much more like Earth. As with the Earth almost all of its carbon dioxide was used up to form carbonate rocks but because Mars lacks tectonic plates, Mars is unable to recycle any of its carbon dioxide back into its atmosphere and so couldn't sustain a significant greenhouse effect. Therefore the water escaped or froze into the ground. The Beagle 2 mission will give us more answers about what happened to the water.
What about manned missions to Mars? When the space missions went to the Moon, the safety point was Earth. With a mission to Mars the safety point has to be Mars. The feasibility criterions on such a mission are:
There are also two big problems, radiation and gravity. These can be overcome by going to Mars when the sunspot activity is at its lowest during its eleven year cycle and the spacecraft must have some sort of artificial gravity for its trip. If it could create 1/3rd gravity, ths would stop muscle and bone degradation. By sending an unmanned lander ahead of the manned lander the fuel for the return leg of the mission can be created on Mars and not carried. This is a large saving as it costs $20,000 to launch 1kg into lower orbit but the whole trip as described here would be about $40 billion. So the unmanned lander can be sent ahead and it would start creating fuel and water by converting hydrogen (brought from the Earth) with carbon dioxide to produce methane and water. The methane will be used as the propellant. Scientists can be sent there and the longer they stay the more we learn about Mars. A type of wheat has also been developed to grow on the Martian soil. This food would also produce oxygen for the astronauts.
Dr. Hiscox also talked about the possibility of terraforming Mars because the Sun will expand as it gets older and this planet will then be too hot for us to survive on. So, if you get to look at Mars, you might be looking at home for our descendants.