Science fiction writers have long imagined a future for humans
on Mars, and Hollywood has created several movie fantasies about what the
experience could be like (with a few improbable aliens added for extra drama).
NASA has addressed the possibility of creating human colonies on Mars someday,
but so far, only robots have stepped foot on the red soil.
How long will we have to wait for science fiction to become
a reality? According to Charles Cockell, a microbiologist at the Open
University in the UK, humans
could go to Mars now.
"Technically, we could go today if we wanted to," he says,
and suggests the reason humans haven't made
the journey yet is because of political concerns. "I think we are ready.
As time goes on, we're going to be more and more ready to go as technology gets
better and life
support systems improve."
Mars has a thinner atmosphere than Earth, so the surface is
more exposed to the sun's radiation and cosmic radiation from the galaxy.
Cockell says human travelers to Mars would have an increased risk of cancer due
to this exposure, and also because of the long, 6-month journey out, since
spacecraft don't adequately shield astronauts from radiation. However, he says
that we could devise shelters to help mitigate this danger.
"You could get people there and back alive with a small
storm shelter on the spaceship," he says. "It's not that bad – you sit in a
box for a couple of days during a solar particle storm. The habitat
for Mars explorers will be an 8-meter diameter tin can anyway."
The first habitat on Mars will be small, but the first
explorers will probably only stay for 500 days before heading back to Earth.
Long-term plans for more extensive habitats on Mars are similar to the
Biosphere 2 project: a completely contained, closed-loop shelter that has
gardens for growing food, recycled water, and other natural systems that use
internal resources to support the humans living there.
Many scientists are concerned that even with a closed
system, a human colony on Mars creates planetary protection problems. Astrobiologists
hope to find proof of native life on Mars, and because humans carry with them
billions of bacteria, we could end up introducing Earth-life on Mars and
corrupting or extinguishing any life that may reside there.
While Cockell agrees we do need to search for indigenous
life on Mars, he doesn't think these planetary protection issues are a major
concern.
"Human microbes are not going to survive for very long on
Mars anyway – they'll die very quickly," he says. "Not a lot of people would
agree with my views, but I would just go there and be done with it. It's not
likely that, even if a microbe did grow, it's going to destroy life on a
planetary scale."
Most scientists think life on Mars would have to be deep
underground in order to access the subterranean water and to stay protected
from the harsh surface environment. Cockell says this means we have even less
to worry about in regards to contaminating Mars.
"On Earth, when you go out to do your shopping, you don't
worry about contaminating the deep subsurface biosphere 3 kilometers underneath
the store," he notes. "That's my parallel with Mars. We've blown up a concern
that isn't really a concern."
"Even if there is indigenous life, the chance of anything
coming off humans or off equipment that's going to cause planetary scale
disruption in the martian biota by finding its way into the subsurface is so
remote, it's not even worth worrying about," he adds.
Cockell says that, to be prudent, we should try to limit the
microbes we bring to Mars, and also catalogue the microbes we know we are
taking with us. Still, he doesn't think too much money or effort should be
dedicated to this aspect of exploring Mars. One exception would be if we
drilled deep into the martian subsurface.
"Then we would have to be more careful," he says. "But
generally I think we can easily do human exploration on the surface without
causing a catastrophe to martian biology. Of course this is all pure
speculation, because we don't know what martian biology would be like, if it's
there at all."
Cockell's enthusiasm to send humans to Mars is part of a
personal dream to go there himself. In fact, he says he would love to be the
first person to cross the martian north pole. He has been to the Earth's South
Pole, traveling with the British Antarctic Survey to study the effects of UV
radiation on microorganisms
"I guess that's one of the reasons I do studies in extreme
environments, because it gives me a connection with Mars," he says.
In that light, Cockell helped create the Earth and Space
Foundation, which funds expeditions that bridge the gap between Earth and space
exploration. In addition to funding field work in extreme environments on
Earth, the foundation has set up awards for future expeditions on Mars,
including one for the first team to reach the summit of Olympus Mons, the
largest volcano in the solar system.
"For the summit of Olympus award, we have a piece of rock
from the summit of Mount Everest and a plaque," he says. "We also put $10,000
into a high interest account, and the money will just sit there. In a hundred
years time, when someone comes to claim it, the award will be substantial."
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