Charles Murtaugh proposes building an undersea colony to test out social conditions in a space colony, with the rationale that it is a similarly harsh environment, and could prove out predictions about the state of civil liberties in such a place.

There are a couple of problems with this. The first is that I don’t know anyone who wants to live at the bottom of the ocean (I know lots of folks who’d like to live in space). I won’t go into the reasons for this right now, but just state it as a fact, at least in my experience. I’ll be interested in hearing of any counterexamples.

The second is that the undersea environment is much, much harsher than the space environment. The only thing that’s easier about it is the cost of accessing it. Everything else, from a habitat-design standpoint is tremendously more difficult.

It’s much easier to design to a vacuum than many atmospheres of negative pressure. The hazards of firing a gun in a well-designed space colony are vastly overblown (pardon the expression), but damaging a negative pressure vessel with a large amount of overpressure would result in an instantaneous and catastrophic collapse.

The third is that space provides interesting and potentially-useful environments for industrial production (large amounts of energy and materials, cheap vacuum, weightlessness). If the ocean were a good environment for technology development/production, the dolphins would have beaten us to the technological punch.

For these reasons (and others) I think that we’ll have space colonies long before we have undersea colonies, but I’m interested in counterarguments.