I had this weird dream where a futuristic USA, to save money, started converting old submarines into spaceships. This got me to wonder how long a modern sub would survive in space, if it were magically transported there. Lets assume the sub is nuclear powered and fully operational.
Any ideas?
I think a major problem you’d have to deal with is cooling the vessel, space is a pretty good insulator.
I’d think on the order of hours. Subs are dependent on the intake and discharge of water to operate. They’d lose reactor power immediately and run on the battery until it died. They wouldn’t be able to make oxygen. The hull would become very hot or very cold, depending on the sunlight.
Well, IIRC, sub patrols are on the order of six months. They’re limited only by the food they carry. But then again, they make their own oxygen and freshwater from seawater. Where ya gonna get that in space?
[hijack]
Better just call the Air Force. Anecdotally, I hear we (the USAF) are taking steps in the direction of spacecrews anyway. . .
[/hijack]
Tripler
Oh, and are your subs boomers or fast-attack?
First off - the nuclear power plants on USN vessels all require gravity to work. Even without that problem, power generation is problematic without a heat sink to keep cooling the condensers. And without the heat sink, there’s no way to keep the condensers as low pressure, so again, you’ve lost power very quickly.
Then there’s the batteries. AIUI nuke power subs have much less battery endurance than the old D/E boats. I think we’re talking on the order of a few hours of emergency power - not 12-24 at near normal operations. That’s assuming that the batteries still work without gravity. Again, this is just AIUI, but I believe that sub batteries are still unsealed lead acid batteries. Once inertia gets involved at all, you’ll have concentrated sulfuric acid running through the battery compartment, with a corresponding loss of power to the rest of the boat.
Then there’s the heat issue - modern subs spend most of their time in near freezing water - 34-35 F. They’re black to be harder to spot from the air. There is some insulation, but again AIUI, a sub is more usually putting heat into the environment from the reactor plant one way or another than it’s worried about cooling - because the sea makes for such a lovely heat sink. The sun would be putting a huge amount of heat into the hull, with no where for it to go. And on the inside, there’s the reactor doing much the same - even if it’s been shut down the moment they find themselves in orbit! In space, the heat generated by human bodies is a not insignificant issue, too.
My vote is going to go to heat stroke killing the crew before CO and CO[sub]2[/sub] poisoning can do them in. With smoke from the battery fire being a distant third place.
But, Tripler, I think that you’d be better off using sub crews to build your spaceship crews from, than air crew. I’ve heard stories about what air crew can do when they get off their shift and they have to fit an extra body into the barracks room. And I’ve never met an airman who knows how to ration water use. 
Heh. The Botany Bay from the original Star Trek episode “Space Seed” was a kitbashed submarine model: Memory Alpha | Fandom
In’d think that instant transport from underwater to space would cause decompression sickness (the bends). How quickly does that kill you?
Conversely,
Generally that’s not an issue - the atmosphere that the crew experiences inside the hull is nominally still one atmosphere. I’m not going to claim it’s exactly 1000 millibars, but it’s going to be close to that. And will remain that even when the sub is in orbit.
After all, if the sub can keep, say, 100 atmospheres of pressure from leaking into the hull, when it’s at test depth, it’s going to probably have the same effectiveness at keeping the single atmosphere of pressure inside the hull when it’s suddenly got stresses in the other direction.
Is that true? My engineering knowledge is lacking here, but I thought it would be problematic that the force on the hull reverses directions.
Probably, but it probably wouldn’t be factor-of-100 problematic.
While an off-the-shelf sub wouldn’t work, it does seem to me that it wouldn’t take very much modification to make it work. Give it some very large heat-sink “wings” that can be deployed after launch (with a silvered side facing the Sun and a black side facing out), cover the batteries, and add a different system for oxygen, and you’d probably be fine.
Telcontar, the two things to remember, are that the expansive stresses on the hull when it goes from 90 ATM pressure to one are not going to be all that different from going from 90 ATM external pressure to zero ATM. The hull is already designed to accommodate a great deal of changing stresses just by existing as it does. The stresses involved in keeping the atmosphere in the hull without any external pressure are going to be different from those stresses the hull is designed for. It’s just that the design factors involved are going to be so over engineered for the situation we’re talking about, that I don’t think it will be that big a problem.
More importantly is that I’m not trying to claim that there’d be no leakage from the hull to the outside. Just that in the time available before one of the other fatal conditions I suggested happened, that leakage would probably be negligible. Ship hulls always leak.
On preview: Chronos, I agree that it seems likely modifications could be made to work with a sub in space. Just that without them, things don’t look good.
Even after you solve all these initial technical problems, the question remains whether the vessel can make it to the planet Iscandar within a year’s time.
[last hijack, I swear–if we want, I’ll open a new thread]
There were some articles I read that dealt with the speed of operations, i.e. airplanes flying around vs. the relatively slow moving submarines, and how the Air Force was better equipped and trained to handle that environment. That, and I’ll even offer that the USAF has more experience in aerospace ops than does the Navy (satellites, missiles, heck even our U-2 and SR-71 drivers are wearing space suits). But, I digress. . .
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You guys hit on what I think is the biggest limiting factor–the reversal of pressures on the hull. I don’t think the sub would work: the construction of the hull would be completely different. IIRC, sub hulls usually get stronger with compression because the pressure compresses pieces together–failure of the hull happens when one particular piece fails at a certain depth. However, take the SR-71, where the frame is loose(r), and as the frame/body heats up due to airspeed, metals expand quite a bit, completing the airframe. I’ve heard anecdotes from quite a few guys (including a pilot) that the SR-71 actually leaked while on the ground until it heated up enough.
Tripler
Oh, and how would you launch the sub’s weapons–no water for steam!
How much protection would the hull give against radiation?
A thick steel hull would give pretty good protection, I would have thought. Better than that available on the Space Shuttle, where weight is minimised.
I’ve long thought that, if we ever get around to building actual spaceships (as opposed to meticulously hand-crafted spacecraft) that they would have more in common with naval vessels than airplanes, in terms of size, complexity, crew, power generation, etc.
AIUI, the thick steel is more of a hazard than help with respect to the high energy cosmic rays one will encounter in orbit.
With pair production, the presence of an atomic nucleus is necessary to have the photon convert to an electron/positron pair. My training was that a heavier nucleus was more likely to act as the focus for a pair production event than a lighter nucleus. So, having large amounts of metal exposed to the same gamma flux can actually result in more biologically damaging radiation near that metal than a light skin, like the Space Shuttle, would allow. My guess is that the thickness of a sub’s hull would be enough to allow for a dramatic increase in the sorts of radiation that can affect biologic tissue, without being thick enough to act as shielding for the secondary effects. With respect to high energy photons, as damaging as they might be, it’s generally considered better to let them pass through a space ship unimpeded, unless it’s possible to effectivley shield against the secondary effects.
(I hope Stranger will show up to expand on this, and correct me if I’m wrong about this.)
There will be areas in the hull that will be fairly well shielded, I think - but that’s going to be because of the effects of various water or fuel oil storage tanks, not because of the metal in the hull.
Reversal of pressure would be a problem for a static tank or chamber. I work with vacuum chambers; their joints and doors are only designed to resist compression. On one of them, we just close the big door (about 3 ft in diameter) and finger-tighten two bolts. Once the vacuum pump is turned on, the air pressure keeps the door closed and airtight. If you tried to pressurize the thing, either the bolts would break or the door would just warp and let air escape.
But a submarine is a vehicle, it’s designed to vibration, shock, bending stress, etc. So it may very well be strong enough to remain airtight in vacuum.
Gamma rays energetic enough to cause pair production are pretty darned rare, but high-energy protons that can cascade to other particles are relatively common. So the point remains, that thick shielding isn’t necessarily your best bet.
