Current Reading - November 2025: A City on Mars and Soonish

I recently finished A City on Mars: Can We Settle Space, Should We Settle Space, and Have We Really Thought This Through? by Kelly and Zach Weinersmith. Earlier in 2025, I read Soonish by the same authors, and it left a lasting impression.

The books are clearly related, but they approach technological possibility from different directions. Soonish asks what may become possible and why it has not happened yet. A City on Mars asks a more uncomfortable question: even if something becomes technically possible, does that mean we are ready to do it?

My interest in space settlement is hardly abstract. Falling launch costs, reusable rockets and the expansion of commercial spaceflight have made human activity beyond Earth feel less remote. But that is also the first useful correction offered by the book: improved access to space is not the same thing as a viable settlement.

A rocket can transport people and equipment. It cannot by itself keep a population healthy, maintain a closed ecosystem, resolve disputes, raise children or establish a legitimate government. I later explored the narrower story of reusable rockets becoming infrastructure, but infrastructure is only the beginning of the settlement problem.

Cover images: Soonish and A City on Mars by Kelly and Zach Weinersmith, published by Penguin Press. Used here for purposes of review and commentary.

On the technical side, A City on Mars largely confirmed what I already suspected. Propulsion, radiation shielding, life-support systems and reliable food production are formidable problems. The book’s treatment of human health and reproduction also makes clear how little experience we have with maintaining a permanent population away from Earth.

Where the book surprised me most was in its treatment of law and politics. I had given relatively little thought to the Outer Space Treaty, the prohibition on national appropriation or the responsibility states retain for activities conducted by private companies.

The authors’ comparisons with Antarctica and the deep seabed are useful because these are places beyond ordinary national territory where access, exploitation and environmental responsibility have required international rules. The analogies are not exact, but they expose the same basic problem: shared spaces do not govern themselves merely because nobody is supposed to own them.

I remain less convinced than the authors that an early space race would readily spiral into war. The immediate commercial returns from a permanent settlement on Mars appear too uncertain to produce a straightforward struggle over profitable territory.

My original confidence on this point was probably too easy, however. States do not compete only for immediate profit. They also compete for strategic position, prestige, technological advantage and the ability to prevent rivals from establishing control first. A location can become politically important before it becomes economically productive.

The book therefore did not persuade me that space settlement should be stopped. It persuaded me that governance cannot be treated as paperwork to complete after the rockets are ready. Rules created after infrastructure has already been deployed tend to inherit the interests and accidents built into that infrastructure. We can already see a smaller version of this problem in orbital debris and the cost of cleaning up space infrastructure.

Of the two books, I still found Soonish the more immediately engaging. Its movement between robotics, biotechnology, energy and other emerging technologies produces a steady succession of surprises. Its curiosity is expansive and infectious.

A City on Mars is narrower and more sceptical. It stays with one ambitious idea long enough to expose how many separate problems are concealed inside it. That gives the book more depth, but less of the exhilaration that made Soonish so enjoyable.

Both books are interested in the future, but neither treats invention as magic. Technology changes what is possible; it does not decide what is sensible, legitimate or just. The rocket may be the most visible machine required to settle another world, but it may not be the most difficult one to build. The harder machinery may be the institutions needed to keep the settlement human.