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.

Considering there is a lot of commerce already going on undersea, if there is any good reason to keep people under there for long periods of time, there would already be companies providing those services. So what's the point of the gov't funding something like this, other than to have the gov't fund somthing like this?

If it's that important, but a money-losing proposition, then the people who want to see it done should get together, start a non-profit, and find some rich donors like Mr.Gates to provide them with the (tax-deductible) funds for it.

Forgive me for being a dimwit, but your post got me, as a layman, asking myself what would the effect of realeasing a certain amount of gas, say equivalent to that of a space colony into outerspace? Would it's mass compact it into ball, rendering it into a mini planet? I read of Jupiter being referred to as a gas giant. And as such (knowing, as I said, nothing) is there a miniature version of such a thing?

Sincerely,

Tom, the amount of gas in a space habitat would be fairly small. If the habitat had a catastrophe that resulted in the gas being released all at once, nearly all of it would dissipate into space, each molecule tending (in the absence of obstacles such as debris or other gas particles) to keep moving in the direction it was moving when released. If this happened close enough to Earth, and if the motion were slow enough, the molecules might be recaptured into Earth's atmosphere.

The amount of gas in even a lesser gas giant such as Neptune has a total mass greater than Earth with its water and rocks and supertankers and people who shouldn't wear swimsuits in public. Nor is it certain those planets are nothing but gas -- although stars are thought to be, and Jupiter has been described in some places as a proto-star (The "2010" movie makes something of this). But it's pretty certain that it takes A LOT OF GAS to create a gravity well sufficient to hold it all in one body.

We couldn't build enough space stations or habitats to contain that much gas.

Yes, gravity (which is the weakest force in the universe, other than the French army) is a very inefficient way to contain an atmosphere. You can do it with much less mass (many orders of magnitude) by simply enclosing it.

Thank you Kevin, for a prompt and enlightening response.

And you're right, people who shouldn't wear swimsuits in public do affect one's perceptions of gravitational pull.

Not that pull should come to mind when encountering such people.

Along the same lines as Raoul's comment, what about learning from the undersea colonies we already have, namely the US Navy's submarine fleet. Ballistic missle subs spend 3 solid months underwater, barring critical mishaps, and are filled to the brim with trained professionals selected for psychological stability as well as competence (also height). No doubt any space program could learn quite a bit. The boomer fleet engages in all kinds of perilous activity, including blind navigation (of a low maneuverability, high inertia vessel) while drilling the crew on the operation of complex equipment, not the least of which are ballistic missiles and the moral overhead that goes with using them. All of that within a framework of secrecy that protects them and their mission.

A bubblehead and an astronaut both face cramped living and working space, limited communications with home (this is getting better than it used to be, but it's still not great), being cut off from society, and having to act on orders that put the lives of the crew at grave risk, in addition to the risk they live with just by being where they are.

Submariners are, I think, more than adequate analogues for astronauts. Their major advantages over astronauts include a smoother launch, gravity all the way through the trip (sea-legs required, though), and provisioning that astronauts could only dream about, since it's so cheap to fill them with food.

A sub may be a decent analogue for "astronauts" in the limited NASA sense, but it's not for a space colony, which is a much more expansive facility. I now very few people who would be willing to emigrate to space if they have to live in submarine-like conditions.

I'd love to live undersea for a year in an enclosure, provided I could see out into ocean.

If you mean a few tens of feet down on a coral reef, sure. There is (or used to be) a hotel in Florida that had underwater rooms, and you had to be a certified diver to stay in them.

If you mean at the bottom of the Marianas Trench, you'd find little to look at, and the bills to keep the lights on to look at what there was would be horrendous.

No, I'm talk way down there, with those 100' glow worms. Maybe spot me a Coelacanth or some such prehistoric swimmy thing with vestigial fingers and elbows...

And we can just light the immediate 5 feet or so outward from the dome -- I'm content to just hang out there and see what swims or floats by...

Would you do it without reading material or internet connection? I think you might be disappointed at how little showed up to entertain you.

Why are we assuming that the undersea colony would be thousands of meters down, where there is no light and little life? This is the equivalent of putting the first space colony in the middle of interstellar space, far from any sun, planets, asteroids or comets.

In other words, the least sensible place to put it. Why wouldn't you put an undersea colony at a shallow depth where there is light, and fish and things?

Actually, I've answered my own question, because if you are shallow, then you may as well be in a
boat, which would be much, much cheaper, and dive down to the bottom whenever you need to go outside.

The point about a space colony is that the access to space is much more difficult that jumping over the side, so it makes a lot more sense to stay there once you are in orbit.

Doh!

Why can't I have reading material? I need to get off line and work on some writing, anyway...

Is booze allowed?