The End of Astronauts: Why Robots Are the Future of Exploration

This is a new book by two astronomers, Donald Goldsmith and Martin Rees, in which the past and future of the exploration of the solar system and beyond is discussed in some detail. As the title suggests, the continued suitability of astronauts for this purpose is a running question throughout the book. Chapters cover projects involving near-earth orbits, the moon, Mars, asteroids, space colonization, the costs of space exploration and space law. No firm conclusions are reached, and the two simply finish by saying that the exploration of Mars is about to become the focus of many groups.

The greatest single obstacle to hands-on space exploration is gravity, because a lot of energy is required to leave the earth's atmosphere. Furthermore, manned space flights are far more expensive than unmanned flights, because the systems necessary to support human life are much heavier than the systems necessary to support robots. Although there have been situations in which a human presence on a space mission has been more efficient than a robotic presence, advances in AI are rapidly closing the gap. One of the disadvantages of human astronauts is their susceptibility to cancer caused by various forms of radiation, which consequently requires heavy shielding on manned flights. Other human requirements in space also increase weight in comparison to robots.

Because of the problem of the earth's gravity, the exploration of other planets and asteroids would be less costly and easier if the missions originated on the moon or other objects with weak gravity. For this reason, there will probably be permanent bases on the moon relatively soon. The far side of the moon would also be an excellent location for telescopes. The authors don't draw distinctions between missions based on scientific advancement, popular enthusiasm, billionaire hubris, commercial interests or geopolitics, so there is no clear perspective defining which activities are appropriate – I found this a little disappointing. They are simply predicting what is likely to happen next. So, in a few years there will be bases on the moon, and in about forty years there may be bases on Mars, the moons of other planets or asteroids. Among the motivators are international competition, the mining of rare elements, curiosity about whether life exists elsewhere in the solar system and the potential development of space habitats for humans. The moon contains helium-3, which could be used to generate energy. The moon, other moons, Mars and some asteroids contain water, which could be useful if bases or colonies are developed. Besides the possibility of human colonies on Mars, some people envision colonies in large, rotating cylinders in space or on the moons of other planets. The authors dutifully mention the hostility of non-earth environments to humans. 

On the whole, I found the book informative about a topic that is likely to become far more important in the future. However, the focus on technical facts omits many of the significant problems associated with non-earth habitation by humans. If the authors had consulted biologists and sociologists, they might have provided a fuller picture of the hazards of space for humans. To me, they have overlooked the fact that, as earth-evolved organisms, humans are unlikely to feel at home anywhere other than on earth or an extremely close simulation of it. I think that living in a Martian colony would probably be like living in a small, remote motel somewhere in Nevada, without the possibility of opening a window or going outside unless protected by a special suit. The authors discuss the terraforming of Mars, i.e., the conversion of Mars to an earth-like habitat. Although that could conceivably occur in the distant future, there is no guarantee that people would be happier there than they are here. Moreover, if humans were to leave earth because it became too crowded, polluted, hot or violent, why would anyone expect that space colonies wouldn't also become too crowded, polluted, hot or violent? If the colonists were trying to escape poor governance on earth, why would they think that they would find better governance in a space colony? I think that, with all the expense and risk associated with human travel to and residence in space, an analysis of what it would take to make living on earth more desirable and sustainable ought to have been made. We have the ability to painlessly reduce the population here by limiting the number of births, and we have the technology to solve the problems of climate change. In particular, it would be far easier to terraform earth, returning it to an earlier state, than Mars or anywhere else, and in this respect the book is extremely shortsighted. In a similar vein, the authors are neutral on speciation. It is true that speciation occurs on its own, as species adapt to changes in their environments, but, speaking for myself, I am perfectly happy being a human. As far as I'm concerned, Elon Musk and his friends can all become cyborgs and move to Mars. Good riddance!