The terraforming of Mars, to a world not unlike ours. Daein Ballard, CC BY-SA
The technological hurdles
Hadfield warns that “we need to invent a lot of things” before going to Mars, and that “there’s no great advantage to being the early explorers who die”. Few would disagree with that, but what are the challenges a crewed mission to Mars faces?
Radiation: An astronaut would receive a lifetime allowable dose of radiation in a single 30-month round-trip, including 18 months on the surface. But this is only equivalent to increasing the lifetime cancer risk from about 20% to
23%. As the majority of this is received in transit between planets, with proper radiological protection on the ship, it would actually be (radiologically speaking) healthier for an astronaut to live on Mars with a radiation dose of
0.10 sieverts per year than to smoke on Earth at
0.16 sieverts per year.
There is no single practical solution to the radiation problem. One
strategy I helped develop was to optimise the internal layout of the equipment and structures in the Mars habitat module to minimise exposure – placing existing bulk in all the right places. This reduced exposure by about 20%, without adding any mass. Even taking empty sandbags, packing them with Martian soil and putting them on the roof would be a simple and effective measure on Mars. Radiation is an issue to tackle, but it’s not a deal-breaker.
Power: “We need a compact energy source,” says Hadfield. “We cannot be relying on the tiny bit of solar power that happens to arrive at that location.”
While the solar energy reaching the surface of Mars is about half that on Earth, this isn’t a show-stopper. A quick back-of-the-envelope
calculation shows that to power the equivalent of
an average US household on Mars, even through dust storms, one would need an array of solar panels totalling six metres square – very achievable.
Gravity Loading Countermeasure Skinsuit.NASA / ESA
With Martian gravity around a third of that on Earth, it would take astronauts a couple of days to acclimatise, and perhaps a few months to fully adapt. NASA and ESA have been developing an
under-suitthat compresses the body to overcome the negative effects of a reduction in pressure and gravity. However, biological adaption could be made easier if microgravity were avoided altogether. The spacecraft could be spun in-transit to generate an artificial gravity that slowly decayed, simulating a transition from Earth to Mars gravity (and vice versa) over the six-month journey.
Ultimately, until humans are actually living on other planets it’s unlikely we’ll solve or even recognise all the subtle long-term health problems associated with reduced gravity. And who’s to say what the advances in bio-engineering and technology will make the human body capable of when that time comes?
The social hurdles
Life on Mars: If there’s life on Mars, even if it’s microbial, should we be allowed to spread to the planet, potentially risking its extinction? I find this question strange – as
Chris McKay put it: “We commit microbial genocide every time we wash our hands”. We engineer and farm the complex life around us as systematically and as cheaply as possible. Billions of people eat the carcasses of organisms that were thinking and breathing only days before. Why, all of a sudden, should Martian microbes be given such sanctity? It should certainly be studied, but it shouldn’t prevent our spreading.
Back contamination: Conversely, the question of whether some Martian plague might accidentally be introduced to Earth should be taken seriously – but not blown out of proportion. There’s only a remote chance that Martian life might be hazardous. The things that kill us do so because they’ve evolved in lock-step with us in a continual evolutionary arms race. Any Martian life will have evolved independently and is unlikely to be capable even of interacting with Earth life on a molecular level. As
Robert Zubrinput it: “Trees don’t get colds and humans don’t get Dutch Elm Disease.”
Psychology: Depending on relative orbits, sending a message between Earth and Mars can take between three and 22 minutes. This loss of real-time communication will leave astronauts feeling cut-off and alone. Hadfield says that it’s vital to keep up crew morale and motivation:
Once you get any distance away on any sort of voyage, the epic-ness disappears, the reality becomes the foreground, and the applause is long gone.
Cost: A crewed Mars programme would cost the equivalent of
a few weeks of the US defence budget. The US plans on spending about ten times more on nuclear weapons than on space exploration over the coming decade. The UK government spends about as much on gastric band surgery through the NHS as it does on its space activities.
So while a Mars programme certainly has challenges to overcome, the technological gap between us and Mars is far smaller than it was for the Moon programme in the 1960s. And the prospects the Red Planet holds for humanity are far greater.
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