Mission to Mars

"Would you go?"

The question was from my office mate, Kelly Foyle, a postdoc working with Christine Wilson on observations of star formation in disk galaxies. We were discussing the first Origins Institute Colloquium of the year which had been given by Canadian astronaut, Dave Williams, on the prospect of a manned mission to Mars.

I considered my answer carefully. To be one of the first humans to set foot on another planet; what an incredible prospect! I could practically hear my eight year old self, fresh from my first trip to a planetarium, jumping up and down shouting 'take me, take me!' And yet ….

"No," I said slowly. "There's too much here I couldn't leave behind for so long."

The problem with Mars is that it's really far away. Both the Earth and Mars are on elliptical orbits around the Sun, which means that their distances from each other changes continuously. The closest they have been recently was in 2003, where they were 55,000,000 km apart. While that makes even a trip round the Earth (40,075 km) seem like peanuts, the furthest Mars and Earth can be apart is 401,000,000 km. This difference is why Mars is sometimes easy to see in the sky and at other times very hard to find.

Because of this distance, an expedition to Mars would take of order three years. It would comprise of 6-7 months travel time to reach the red planet, two years on the planet surface and another 6-7 months for the return journey. For comparison, the moon can be reached in three days while journeys to the International Space Station are quicker still. This presents any would-be expedition with a problem that has never had to be tackled before; what do you do when something goes awry and you can't just come back? All previous space trips have been able to have the back-up plan of returning to Earth quickly if necessary, but a Mars-bound vessel would have to 'abort to Mars' once it was sufficiently far away from Earth. Any repairs or necessary adjustments would therefore have to be able to be performed while in space with the tools and supplies already on-board. Even though advice could be received from Earth, the twenty minute latency on communications from Mars to Earth would be too long for medical procedures to be conducted via this method; the knowledge as well as the equipment would have to be with the astronauts themselves.

In addition to this, Dave Williams placed a lot of emphasis on the problems of keeping the astronauts healthy, both in body and mind. In the low gravity of space, the human body can start to waste away which causes problems when the astronauts return to Earth. For instance, while astronauts use their arm muscles to propel themselves around the space craft, their leg muscles get little use and loose their strength. The heart muscle deconditions and bone density drops at a rate of 15% per month. Astronauts can also suffer from lower back pain as their body elongates in an environment free of the downward pull of a planet. Dave revealed that he is 6' 1'' on Earth but almost 6' 3'' in space. There is also the unknown long-term effects from exposure to cosmic ionizing radiation; high energy particles that we are shielded from on Earth by the protective cocoon of our atmosphere. Dave explained that when you close your eyes in a dark room in space, you can still 'see' flashes of light that come from this radiation passing through you. What damage they might do over a long period of exposure is unknown.

There is also the mental strain of being contained in a confined area in extreme isolation for such a prolonged period of time. Entertainment and variation in food will also be difficult, since astronauts will grow bored of eating the same meals for several years.

Once on Mars, the astronauts will be in a strong gravity field once again, although Mars' gravity is only 40% that of Earth. However, unlike on Earth, there will not be people able to help the new arrivals until they can re-adjust to the forces on their body and there will be much work to do.

To combat these problems, exercise machines have been developed specifically to keep astronauts in shape while in space. Harnesses are used to pull the user down onto the running machines and a DVD player screen help maintain a sense of orientation. Meanwhile, the University of Guelph is researching into producing crop yields on another planet and NASA are exploring different possibilities for transportable shelters to take to Mars. Dave mentioned the idea that the perfect candidate for this mission might be different than for previous expeditions into space, due to the long duration and uncertainties being faced. He suggested that older people in their 70s might potentially prefer to make the journey, since their families would be grown and long-term health effects that could occur 10-20 years later would be less of an issue.

While the space program may not yet be recruiting astronauts specifically for the Mars mission, Dave thinks there is a high chance in it happening within our lifetime. It was a strange thought to think that you could be sitting beside the first person who will set foot on an alien world. Who knows? When I reach 70 I might even change my mind and be signing up myself!

So what is it really like in space? Dave told us that he gets the most questions about how astronauts shower and use the toilet when they stay at the International Space Station. He describes the shower, which looks like a cylinder with a lid. Soapy water is used to cover your body which is then vacuumed away. The toilet, he said, uses another vacuum system. The basic idea of such a device is that you want things to go away from you. On Earth, gravity does all the work when you flush, but in space a vacuum has to be used to remove the bodily waste from the toilet bowl, where it is then stored and returned to Earth. This final point left Masters student, Mikhail Klassen, with one question:

"Why, oh why do they bring human waste back to Earth when there is infinity on all sides of you?"

It was a mystery that would have to be left for another day.