On to Mars!

life_on_marsOne of my favorite quotes is, sadly, unattributable (at least as far as I’ve been able to find): “The cowards never started and the weak died along the way.” I first came across this in an explanation of why the American West is traditionally more of a bastion of rugged individualism than is the East – the people who set forth to explore and settle the West were made of sterner stuff than the wimps who stayed behind. We can debate whether or not this is true until we’re blue in the face, and that’s not the point of this posting.  But regardless of where you come down on the hardiness of those who settled the American West (or any other frontier for that matter – remember that even the effete East was once frontier!) I’m guessing you’ll agree that those who set off to explore and then to settle parts unknown faced some tremendous risks.

Consider, for example, the “heroic age” of Antarctic exploration. How many people died just trying to be the first to reach the continent, and then to be the first to tread upon the South Pole? Shackleton became legendary without even reaching the pole, simply by keeping his men alive during his ill-fated trip a century ago. Reading about the hardships and the risks that all of the early polar explorers endured makes me feel like a wimp to be honest with you, but it’s also uplifting to realize that people like me were able to accomplish so much and so great a price to themselves – that they overcame tremendous obstacles simply in order to be the first: the first humans to reach a particular destination, the first of their family to own land of their own, the first to accomplish something great, whatever that might be.

I think that we lost something when we filled in the last of the white spaces on the map, when we reached the last of the unknown places on Earth. Yes – there are places that are still unknown to us (the deep ocean being the biggest) – but what we’re doing now is tidying up rather boldly striking out for parts unknown. Maybe this is why science fiction is so popular – we are well past the age of heroic exploration on Earth and, with NASA stuck in a holding pattern a few hundred miles up, the only frontiers we have are fictional. The question is whether we’ll ever see another frontier open up and whether or not we’ll see humans setting off again for a place where no person has ever stood.

One of the problems with deep space, of course, is that it’s a dangerous place. No air, millions of miles to the nearest food and water, stray comets and meteors, and a long ways from roadside assistance. And then there’s the radiation as well – outside the protection of Earth’s magnetic field radiation levels are much higher than what we experience at the surface of our planet, and the radiation that suffuses space is a lot more damaging than what penetrates to sea level (or even to the mountaintops). For this reason, there are some who wonder if the risks from radiation in space are so high at to preclude our ever leaving our world to visit another.

The traditional way to protect against radiation is to use some combination of radiation safety’s trinity – time, distance, and shielding. Reducing the time spent in a radiation field reduces your dose, increasing distance also reduces dose, and installing shielding helps protect against radiation as well. On a spaceship, however, there’s not much that can be done about time – the trip takes as long as it takes, in the case of a trip to Mars that can be over a year in space. Distance is another factor that can’t be controlled – radiation dose will drop as the ship travels further from the Sun, but not significantly, and in any event, Mars lacks the Earth’s thick atmosphere, so the astronauts will be exposed to elevated levels of radiation even on the planet’s surface. That leaves shielding. The problem here is that shielding can be heavy and every pound of shielding lifted into space is one pound of supplies (water, air, food) that has to stay behind. This part can be finessed a little bit, say by using drinking water as a radiation shield, or by shielding only a relatively small “storm cellar” to be occupied during the worst space radiation storms. But there’s only so much that can be done about shielding radiation on a spaceship – at least, with our technology.

Some recent studies suggest that astronauts traveling to Mars might be exposed to enough radiation to raise their risk of developing a fatal cancer by about 3% – maybe more if we also consider the radiation dose they’d receive on the surface. In the US the risk of dying of cancer is about 25%, so Mars-bound astronauts would see their cancer risk increased to 28% or more if these calculations are correct. This would be more radiation dose than any astronauts have ever received and it is certainly something worth trying to minimize. The question is whether it’s enough to keep us from trying to set foot on Mars at all. Personally, I would hope that this is not the case – that we try to send people to Mars even with this elevated risk.

First, let me be clear that I don’t consider this to be a trivial risk – outside of wartime or response to a serious emergency I’d be hard-pressed to think of a situation in which I’d order someone into a situation in which they had a 3% chance of not coming back. But we’re not talking about ordering astronauts into a risky situation against their will – we’re talking about selecting from among a group of volunteers – and I’d be willing to bet a lot of money that NASA will have far more volunteers than available spots for the first trip to Mars. Not only will the first Mars astronauts be volunteers, but they will be incredibly well-informed volunteers and will likely know enough about the health effects of cosmic radiation to make an informed decision. But let’s face it – we have all heard of athletes who have said that they’d accept permanent disability and risk of death from taking performance-enhancing drugs if it gave them a chance to set a record or to win in the Olympics – why should this attitude and willingness to take risks not be shared by explorers as well? And in the long run, which is more memorable – the athlete who shaved a fraction of a second off the world record for the 100-meter sprint, or the first group of people to leave Earth orbit and walk on another planet. If we are going to let a group of people volunteer to accept a higher risk, how can we say that it’s OK for an athlete but not for an astronaut?

The bottom line is that the risks faced by astronauts are not insignificant – there have been deaths in space (and in trying to reach space) since the first days of the space program and these deaths will continue. But any new frontier has risks – Magellan’s expedition lost the great majority of its crew (including Magellan), and every other explorer from that era lost men as well. This is not to say that it’s OK for people to die during exploration – just that it happens, and that we go on to explore and to open the new territories because what we gain is so much more than what we have lost in the process. Those who died so that Magellan’s expedition could succeed, those who died during Captain Cook’s voyages of exploration, those who died settling the American West (settlers and Native Americans alike) – they died heroically, placing their lives at risk in the service of something that they believed was worth the risk (in the case of Native Americans, they died to preserve a way of life that was substantially different from that of the predominantly white settlers). Who are we to tell astronauts that they cannot do the same? Or have we become so risk-averse, so cheap, and so narrow in our outlook that one chance in 33 of developing cancer is enough to cause us to turn away from the greatest voyage in history?

 

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3 Responses to “On to Mars!”

  1. Ahmed Ali Abdi June 17, 2013 at 2:38 PM #

    is that you. Dr Y. quite familiar picture. we always value science monk blog as generous scientific bulletin. what is the archaeological difference and similarity the planet earth and mars? what is the nature of the mission mars? which planet could cover the earth scarce resources remain greater as alternative resources?

  2. Mark Schanfein June 18, 2013 at 1:44 PM #

    I really enjoyed this article, but of the radiation safety’s trinity, time can in fact be shortened to reduce a traveler’s radiation exposure. Advanced nuclear rocket technologies can provide propulsion continuously, as opposed to our current use of gravity based trajectories. These engines are far from new, see NERVA.

  3. Dr. Y June 23, 2013 at 4:46 PM #

    Ahmed – thanks for your kind comment and question! Let me see what I can do to answer.

    Both Earth and Mars are relatively small rocky planets (compared to the gas giants of the outer solar system). They both have relatively thin atmospheres compared to the gas giants and Venus, although Earth’s atmosphere is much thicker than that of Mars. It also seems almost certain that Mars used to have liquid water flowing on its surface – the Mars rovers have shown ample evidence of that in many locations – and of the planets we’ve sent spacecraft to, Mars seems most likely to have once had life on it (although some of the moons in the outer solar system are also candidates).

    A mission to Mars would likely take at least a year and probably closer to two years (although, as Mark points out, higher-power rockets can shorten this). Unlike the Apollo missions to the Moon, any visit to Mars would likely have to set up to stay on the planet for a prolonged period of time – this would give the astronauts plenty of time to establish a base and to study the planet, although it also means that they’d be out of reach of help for a prolonged period of time and there would be more opportunity for problems to crop up.

    Not sure what Mars might offer as far as resources go – we need to know more about its geology to answer that. But it’s not likely that we’d be able to economically mine Mars for minerals or metals because of the incredibly high cost of travel to and from another planet. On the other hand, there are many who feel that we should still establish a colony on Mars anyhow, if only to protect humanity against extinction in the event of a catastrophic cosmic collision like the one that led to the extinction of the dinosaurs.

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