rock and roll won't cut it

My current book is A City On Mars, by the Weinersmiths. The short-short summary is that space travel is really hard, and that people who are optimistic about a permanent human presence in space have mostly not thought about the problem hard enough.

I think I'm about halfway through? One of the quirks of audiobooks is that you can totally lose track of whether you are near the beginning or the end of a long book. This can be a good thing for fiction, where a small number of remaining pages can constrain how the plot might end up. (But it has its downsides, too.)

Anyway. The first parts of the book are about the technical problems of colonizing space. Many of these problems have solutions-in-principle: after all, there have been people living continuously on the International Space Station for a quarter-century now. But the International Space Station is, in its entirety, roughly the size of a school bus or three. It's certainly not large enough to host a self-sustaining colony.

(The authors prefer to use "settlement" rather than "colony," finding the former slightly less tainted by the history of conquest than the latter.)

Some discussions about whether a lunar or Martian colony might be self-sustaining will mention which chemical elements have been detected on those bodies. That sort of essentialist analysis has always struck me as silly, but the Weinersmiths have a pithy retort: compare the value of your cell phone before and after you grind it into a powder. Energy and material will always be at a premium. The most likely locations for settlements are underground. (Lava tubes, which form natural and stable underground caverns and whose existence is attested on both (I think) the Moon and Mars, are an attractive way to avoid an industrial excavation task.)

Some of the settlement challenges are environmental. Everybody knows about vacuum, which is even an issue in the thin Martian atmosphere. Many people know about radiation. Folks tend to be unsurprised when learning about how large temperature swings can get when going between sunlight and dark without any atmosphere to carry away heat. But a major challenge for settlements, already experienced by human lunar explorers and both lunar and Martian robots, is the regolith. Regolith is unweathered shards of glass and stone, which frequently acquires an electric charge and therefore sticks to everything. Lunar astronauts complained about how hard it was to get rid of. Rinsing with water is unlikely to be economical, given the expenses associated with water. And Martian regolith has a high concentration of perchlorates, which would poison plants unless the regolith under the garden were processed chemically.

The later parts of the book, where I am right now, are about "space law": what legal frameworks govern whether folks in space can do this thing or that thing? There both is and isn't a well-established set of international agreements. There is an Outer Space Treaty and a couple of sixties-era follow-on agreements, which are widely agreed to but rather vague on details. The book has a pretty interesting discussion about what law is, in general. After all, violations of "international law" by this or that state can really only be "prosecuted" by shame or isolation from the international community. In principle the Moon and Mars are an international commons, a la the Antarctic or the seafloor. There are some interesting questions about whose national sovereignty applies to what regions. But apparently the United States has promulgated a policy since about 2015 that private actors can claim private ownership of space resources by extracting them: you can't own territory, but you could own regolith.

This is kind of a sprawling and disorganized review of a long, thoughtful, and carefully organized book that I haven't finished reading yet. But! I recommend it.