Reviews Physics World  October 2020

Intrepid interstellar adventurers

Red rovers Current plans for a habitat on Mars could be just the start of human settlements in space. (NASA)

Ian Randall reviews Spacefarers: How Humans Will Settle the Moon, Mars, and Beyond by Christopher Wanjek

It’s the year 3000 and your great, great, great granddaughter is swimming in Kraken Mare, a gigantic lake of liquid methane and ethane, on Saturn’s moon Titan. The low gravity allows her to leap up and out of the water like a dolphin breaching. As she does so, her enormous eyes (inherited from her father, whose family evolved them on dimly lit Mars) peer through the lenses of her thermal suit at the surrounding deep-hulled sailboats zipping along. In the hazy distance, giant server farms pump out their excess heat into the usefully chilly –180 °C surroundings. Inside, trillions of uploaded human consciousnesses do, well, whatever the digital equivalents of brains-in-jars do, I suppose.

This vivid vision of future recreation is just one possibility teased out in the course of science journalist Christopher Wanjek’s enchanting new book, Spacefarers: How Humans Will Settle the Moon, Mars, and Beyond. The work is rich in detail, accessible, refreshingly frank and compellingly written – in fact, I would go as far as to declare it, hands-down, the most enjoyable piece of non-fiction I have read in years. Starting with a captivating review of humanity’s current progress on the path to settling other bodies in the solar system – from geopolitical drivers to financial constraints – Wanjek explores the challenges and motivations of recreating the Earth-like conditions necessary for our survival, out in space and on neighbouring worlds.

Of note is a running (and particularly candid) assessment of NASA’s activities and administrative challenges, which offered much food for thought. Launching from this foundation, the second half of the book sets out to envisage what our future in space might be like. They range from the current interest in returning to the Moon and the challenges of having sex in space – all the way to extracting helium-3 and nitrogen from Uranus to power future fusion reactors and populating the atmospheres of majestically spinning, orbiting cities assembled across the solar system.

It should be said that, for me, Wanjek’s work is stronger when engaging with present-day and historical material. The latter half of Spacefarers is (while no less riveting) obviously speculative, with all the incertitude that such an undertaking makes inherent. There is not a small amount of irony in that Wanjek kicks off the book by criticizing the depictions of space travel in film and, later, the fantasies of some futurists. While I suspect that I shall greet much science fiction now with a more sceptical eye, some of his suggestions (as alluded to above) hardly seem less fantastical.

There were a few aspects of Spacefarers that I did find frustrating. At various points, Wanjek envisages off-world settlements as being appropriate for a certain type of retirement community. Until the final third of the work, however, the reasons to create such a “space Miami” did not seem well articulated – the ultimate rationale seems to be to find a demographic of settler unconcerned by the long-term risks of heightened radiation exposure, the weaker gravity, and potential complications around gestating children.

In the opening chapter, meanwhile, a colourful anecdote about Russia’s first experiment to simulate the psychological and physical impacts of long-term confinement during an interplanetary mission – the usefulness of which was compromised by an episode of drunken fisticuffs and sexual harassment – would have benefitted from a more explicit condemnation of the latter behaviour. That is especially so in the light of the many challenges women face working in STEM fields, not to mention their general side-lining in space programmes to date. Instead, Wanjek immediately notes that a similar experiment conducted almost a decade later, the Mars500 mission, “went more smoothly, as Russia decided to exclude females” – a statement that manages to couple implications of victim-blaming with phrasing many consider to be derogatory as well as grammatically awkward. (Where’s the noun? Are we even talking about humans?)

Similarly, a later joke about the “obscurity” of the Italian Space Agency also read poorly. When added to the awkward implication in the same chapter that “grown men” are only justified in hugging and kissing with “good reason” (that is, celebrating successfully landing tech on Mars), it served to further the unfortunate overall impression that the author’s values might not be quite as progressive as his vision for humanity’s next steps off-world. This may be an accidental misrepresentation in poorly chosen words – and certainly these are minor points in an extensive work – but they sadly detracted from my ability to recommend this book with a total lack of reservation.