We might make it beyond Mars—but only if we can build radiation shieldsby Frank Close / December 22, 2015 / Leave a comment
The Soyuz TMA-19M space ship blasts off for the International Space Station from Baikonur cosmodrome, Kazakhstan, Dec. 15, 2015. The Russian rocket carries British astronaut Tim Peake. ©AP, Dmitry Lovetsky Read more: Alien megastructures: we shouldn’t search for ourselves in the stars Read more: Water on Mars: we need to be careful how we investigate other worlds When Major Tim Peake arrived at the International Space Station, it was the climax to a dream that began for me 11 years ago. In 2004 the Royal Astronomical Society asked me to chair a review of the pros and cons of Human Space Exploration. The United Kingdom had a long and successful tradition in robotic ventures into space, but had held back from exploration by humans. Small is beautiful, so I kept the committee to just three people. My colleagues were Ken Pounds, former chief executive of the Particle Physics and Astronomy Research Council, and as such responsible for much civil research in space, and John Dudeney, Deputy Director of the British Antarctic Survey, and veteran of 20 trips to Antarctica. The experiences of scientists who have been isolated for long periods in the Antarctic base could be invaluable in preparing astronauts for extended trips into space. The 2007 report of the UK Space Exploration Working Group, worked on by Frank and the British National Space Centre. When we began, we were sceptical about the advantages of humans over robots. Where humans are involved, risks escalate, as do the costs. Yet by the time we completed our report, in 2005, we were strongly supportive that Britain should get involved in human space exploration. This led to UK Space (BNSC as it then was) to ask me to chair a large group of experts to evaluate the question, on their behalf. In 2007 we recommended that a British astronaut at the ISS could be a first step. Little did we dare to hope that we would see this happen. Why were we enthusiastic, and what did I learn from these studies? First, and most obvious perhaps: reality is not like Hollywood. Exploration of space beyond Mars seems likely to be forever the preserve of robots. This is not simply because of the vast costs, huge time-spans and the psychological implications for astronauts and their families, though these alone are sufficient to give pause, but because of a natural phenomenon: radiation in space. Cosmic rays, the solar wind, and other high-energy particles are ubiquitous. Their effects on human tissue can be lethal. A journey to Jupiter, for example, would subject an astronaut to the equivalent of radiation treatment for cancer over every bit of their body. In short, they would be dead. On Earth we are protected from this lethal cocktail by the magnetic field and the atmosphere. Unless some way is found to create some radiation shield, which can be transported along with the rocket and crew, this seems to be a showstopper. In the absence of that, Mars is the likely limit. Even Mars is at the limits of what may be acceptable, however. The effects of radiation are cumulative and, as any oncologist knows, wrapped with probabilities. Thus it is not so much “you are safe as far as Mars and then its lethal” as “there is a 50% chance than in the next 50 years you will have received a lethal dose”. Once one accepts this, one’s image of the “ideal” astronaut might change. The Hollywood image of a glamorous young female, as personified by Anne Hathaway in Interstellar, is not at all advisable. With up to 70 years of life to look forward to, and yet to have children of her own, the radiation odds would be awful. Contrast with an astronaut of more mature years. A fifty year old might be quite happy to know that in fifty years’ time they “only” have a fifty percent chance of anything bad happening to them. One of the joys of our enquiry was to discover that many of our preconceptions were way off the mark. So beyond the orbit of Mars, the outer planets, their satellites and the asteroids, look likely to remain the preserve of robotic probes. Wonderful advances have already been made this way during the last 50 years. The Voyager spacecraft has even travelled beyond the limits of the solar system into deep space. As for Mars, and the Moon, however, humans have a lot to offer. Robots are excellent for first exploration, with cameras to transmit close up images, landers with robotic arms that can take and even analyse samples, by which we have learned much already and will continue to do so. They are first rate when programmed about what to look for. Humans, however, have the ability to generalise and to recognise and act on serendipity. We can make on the spot decisions in ways that robots – at least for now – cannot. While Mars is loved by US presidents and by Hollywood, it is at the limits of where humans are likely to venture. By contrast the Moon is relatively near – only about ten times more remote than geostationary satellites. The far side of the moon is permanently shielded from the Earth, and as such is a unique place in the cosmos where all radio and other electromagnetic “noise” from our planet is obscured. As a site for radio astronomy, therefore, this would be ideal in principle. To make it so in practice would require some human presence, at least in the initial stages of preparation. The Moon is also likely to be rich in minerals. Robots can drill, but in reality problems arise: a drill gets stuck or broken; samples reveal that a better location is elsewhere, any number of issues that humans can deal with in ways that robots cannot. One opportunity, which impressed us and we highlighted in our report, has already been realised with Tim Peake’s adventure: the inspiration for a new generation of potential scientists, engineers and technologists. The two committees, which I chaired, were populated dominantly by children of the era of Yuri Gagarin and Apollo, and the radio thriller: “Journey Into Space”. We recall the impact that human space exploration had on our generation. The Apollo missions were correlated with an upsurge in American PhD’s in science and technology, for example. We drew specific attention to the potential inspiration that a British astronaut could have for children in the United Kingdom: “We find compelling evidence that the outreach potential for HSE can be a strong positive influence on the interests and educational choices of children towards science, engineering and technology.” As thousands of excited children watched Major Tim Peake blast off from Kazakhstan, I saw that prediction come true. Now I hope that some of the other benefits, which we identified, will in due course also come to pass. Every journey begins with a single step.