From my eight year old -- an underwater space station. Basically a blob of water in space with a space station in the center. The outside would freeze solid and the inside would remain melted. A good source of water, self-healing (refreezing) if it was hit by a meteor, protection from cosmic radiation. Plus you could swim around and maintain the space station in scuba gear instead of a full blown space suit -- and no worries about floating away because the water gives you the ability to swim in any direction without thrusters. The more I think about it, the better I like it.-- terryo, Mar 28 2014 comets https://en.wikipedi.../wiki/Comet_nucleus [Voice, Mar 29 2014] Shameless self-promotion, reminded me of this... Low_20budget_20spacecraft [normzone, Mar 31 2014] Also reminds me of Space_20JamMore shameless self promotion [RayfordSteele, Apr 02 2014] Methane airplane http://spinoff.nasa...ne-Powered+Airplane [RayfordSteele, Apr 02 2014] Oil and Water in Zero G http://www.our-spac...er/liquids-in-space [MisterQED, Apr 04 2014] Planequarium Planequarium [theircompetitor, May 21 2014] I was thinking maybe you could put algae in the blob for CO2 recycling, but you'd lose other gases along the way, outgassing.
I think the biggest problem you'd have with an uncontained blob of even ice would be the tendency to vaporise. I suppose comets keep most of their ice, so maybe this is too long term to be of concern.
Also it would probably cost a pretty penny to transport so much water into orbit.
[+]-- skoomphemph, Mar 28 2014 Your kid has a great imagination. Cultivate it. [+]
And welcome to the 'bakery. This idea will generate a long anno stream, because it's very nearly possible and that starts everyone thinking.-- Alterother, Mar 28 2014 Welcome to the Halfbakery, [terryo]. You'll feel more comfortable when you accept that there's no way out.-- MaxwellBuchanan, Mar 28 2014 [+] good one, 'grats your kid. Warmth from the space station would keep the water nearest it liquid.-- FlyingToaster, Mar 28 2014 Welcome.Love this idea. Very Niven-esque.The Integral Kelp.-- 2 fries shy of a happy meal, Mar 28 2014 As long as you're okay with various rocks and gasses in your living quarters there's no need to ship water into orbit... (link)-- Voice, Mar 29 2014 If you're going to put in in earth (or earth's) orbit, you're probably going to need a sun-shade on one side, and lots of radiators on the other, possibly a heat pump or two to keep the shell frozen and the center livable. Put solar panels on the sunshade to make a virtue of necessity.
It's only going to work outside of the Roche limit, and ideally, you'd want it to be large enough to maintain it's shape through gravity, which is fairly massive (I'm honestly not quite sure how massive, Ceres is mostly water and manages it at ~10^21 kg, but Hygiea manages it at ~10^20kg and is rocky and which suggests it might be much lower for water. You're probably still looking to slam together several comet nuclei for that effect.
Otherwise, you're probably looking at putting a skin around the ice to keep from to much being lost to micro-meteor ablation and the like.
All that being said, I like the concept. Welcome to both you and the young-un.-- MechE, Mar 29 2014 It's going to need to freeze solid during any course corrections.-- WcW, Mar 29 2014 This is great. A few feet of water is an excellent radiation shield, water is a whole lot easier to swim around in than space. It is a phenomenal heat sink. You can even engineer it really easily... making bit frozen projections with a liquid core if you needed more heat sink area.-- bs0u0155, Mar 29 2014 My [+] is contingent on there being goldfish. Like canaries down mines, they could alert the astronauts to potential disasters, such as extremes of temperature, increased radiation levels, or a malfunction in the sunken treasure chest that releases bubbles.-- MaxwellBuchanan, Mar 29 2014 But.... how would they float on their sides at the top? Which way is up?-- bs0u0155, Mar 29 2014 "Up", for a goldfish, is towards its dorsal fin. I would have expected anyone to know that.-- MaxwellBuchanan, Mar 29 2014 Dibs on the Zamboni contract.-- FlyingToaster, Mar 29 2014 [Max] The only one true way out is through the mind . This could definitely be a stepping stone. [terryo] you must be full of pride, I would be.-- wjt, Mar 30 2014 This Idea has a problem known as "sublimation". Things near the Earth (and Mars) receive enough sunlight that ice will evaporate, and then be carried off by the Solar Wind. Your block of ice will need to be protected from sublimation, if it is any closer to the Sun than, say, the Asteroid belt.-- Vernon, Mar 30 2014 You'd want to start off with a plastic bag covering it, or you'd waste water waiting for the outside surface to freeze.
So... what happens when it's hit by a ball bearing at 75,000mph ?-- FlyingToaster, Mar 30 2014 "I was born in a water moon. Some people, especially its inhabitants, called it a planet, but as it was only a little over two hundred kilometres in diameter, 'moon' seems the more accurate term....." RIP-- not_morrison_rm, Mar 30 2014 I think a blob of water in space would boil off due to near-vacuum pressure, no?-- tatterdemalion, Mar 30 2014 Could this not be done with jelly?-- MaxwellBuchanan, Mar 30 2014 Sublimation is only an issue if the mass isn't sufficient to retain the vapor by gravity. If it is, it will sublimate until the partial pressure of water vapor around the sphere is sufficient to prevent further evaporation.
If it isn't, see my above on recommending a thin skin.-- MechE, Mar 30 2014 You realize this is another reason to hollow out the moon.-- 2 fries shy of a happy meal, Mar 30 2014 I'm stll all mathed out from black body stuff, or I'd try to run up some figures on this, but I don't think sublimation is going to be a big problem if you keep the ice smooth (ie: transparent).-- FlyingToaster, Mar 30 2014 /course correction/ Why would it need to be solid during course corrections, WcW? Would an engine or tug on the outer shell not suffice?
This does have the smell of High SF about it. not_morrison, what is that water moon quote from? Is that David Brin? Startide Rising?-- bungston, Mar 31 2014 bungston - The Algebraist.
Not as in bungston, the algebraist. Unless you are good at algebra..in which case...oh, I give up...-- not_morrison_rm, Mar 31 2014 [Vernon] you may be right about the sublimation rate, at least according to a graph I found... if the sphere was a black body, then orbiting around the Earth it'd equilibriate at about -20C, at which point the sublimation would be measured in cm of depth per hour. Ouch.
But it's not a black body. It doesn't absorb all the radiation thrown at it. Getting the temp down to -70 or 80 and you're talking 1cm every 10,000 hours or so.-- FlyingToaster, Mar 31 2014 Very imaginative idea. And, welcome.-- the porpoise, Mar 31 2014 I like this. It's one of those ideas you could easily discount for boring practical reasons - but then you can think - unless...
Suppose we coated it with a thin film of something to prevent water loss. Ideally self-healing, but at least not something which would tear when punctured. If it's frozen, then a layer of paint might do - and you can then just repeat the process every now and then, or patch any cracks.
You'd need at least one robust entry/exit portal. Two or more would probably be best, for efficiency, redundancy and safety. Then we could have a hollow core, connecting at two poles. Larger ships could then fly through without having to turn round.
You might also want to put up solar panels on the sunside. This would get that external temperature down, and you can use the joules in the middle to keep the living space temperature up as a side-product of doing useful work.-- Loris, Mar 31 2014 [+] Yes, and I see this grabbing comets that pass by, to cultivate the required mass, & then some.
If it was gathering comets to help sustain the gravity & water required, then why stop there? Just keep harvesting & grow this puppy into another moon, but this time, controlled.-- sophocles, Mar 31 2014 Only problem I can see with the comet-grabbing idea is that if you grab a comet, it grabs you. You'd have to have a way getting your target comet to steer itself in a favorable direction, otherwise the "new neighbour" might drag you off to some destination neither of you would survive.-- skoomphemph, Mar 31 2014 [skoo] yes, the pesky momentum problem. But, that could be solved by tracking 1,000's of comets, & then tweaking their trajectories (via small remote probes) to make sure they collide at the same time, from opposite directions, with comets of the same mass. All quite doable, of course.-- sophocles, Mar 31 2014 Wow. Thanks for all of the interest. I AM proud of that little guy -- he has a lot of ideas, some really interesting (immediately after thinking about this he "upgraded" to an under-LAVA space station so he kind of jumped the shark there ... then there was the cow-powered airplane that shoots cows out of the back for propulsion with giant trampolines to catch them aaaand the conveyor belt that shoots the cows is powered by ocelots!)-- terryo, Mar 31 2014 Maybe a layer of oil on the outside would prevent sublimation. And also keep it from freezing? I want the manta ray spacefarers to be able to jump out into bare space and land back in the water.-- bungston, Mar 31 2014 This whole idea reminds me of a scifi short that I read in a compilation; different premise, yet parallel notions. I'll try to find it.-- Alterother, Apr 02 2014 Anything to do with Blue Champagne, John Varley?-- normzone, Apr 02 2014 ...cow-powered airplane... would he settle for a cow poo powered airplane?-- RayfordSteele, Apr 02 2014 ^^ No, but it has the left-field feel of Varley's best work.-- Alterother, Apr 02 2014 I don't think cows shoot them out fast enough to power a plane.
And now for some reason (or non-reason, more likely) I now suddenly remember that a cow once stood on my foot. She was a Friesland, and was just the last part of a chain reaction caused by one of her sisters getting spooked by her food crib.
When a cow stands on your foot, there's nowhere to run to. You just stand there discovering what an expressive face you have when it comes to expressing pain.
Perhaps if you spooked the cows they'd fire out their cow pats at a higher speed?-- skoomphemph, Apr 02 2014 I've got my eye on the Jersey up the road ... oops, wrong online community! I mean ...
I was just implying ...
Well it's like this ...
hng .. grng .. er later ...-- skoomphemph, Apr 02 2014 I had a Clydsedale do that to me on purpose once. Ornery bastard. You're right, there is really very little to be done about it.-- 2 fries shy of a happy meal, Apr 02 2014 Avoiding barnyards is a step in the right direction.-- Alterother, Apr 03 2014 That's what I was trying to explain to the Clydesdale.-- 2 fries shy of a happy meal, Apr 03 2014 At least the cow did it accidentally. And at least a cow weighs only about 500 kg if she's huge. I thought Clydesdales were gentle beings. I'll watch myself next time I'm around one. (I know you have to be careful of palfreys, because often they bite, but I thought one could always trust a heavy horse.)
The police heavy horses are trained to lean against the perps they run down, apparently. It requires a wall to work with, but there are plenty of those around.-- skoomphemph, Apr 03 2014 Cudos (+) (terryo) Jr. for the idea. I agree with (Loris) this is one of those ideas that you immediately dismiss and then think but... I originally came up with the same result as (bungston) and thought oil film skin but that won't work (link). Maybe ferrofluid?-- MisterQED, Apr 04 2014 //Cudos (+) (terryo) Jr. for the idea.// I think you mean "kudos".
"Cudos" is either Latin for "mint", Lithuanian for "marvel" or Sao Paulo street-slang for "testicles".-- MaxwellBuchanan, Apr 04 2014 //oil film skin but that won't work//
If your puddle is large enough to hold together under it's own gravity, it will work, albeit very slowly.-- MechE, Apr 04 2014 Having the perimeter bound by phospholipid bilayers has a nice feel to it..-- bs0u0155, Apr 04 2014 wax ?-- FlyingToaster, Apr 05 2014 I just realized that floating around in water would (pretty much) negate the effects of extreme acceleration. Unless I'm wrong. Which happens. My thinking is that the body is WAAAY closer to water in density to water than air and a little acceleration would only pull the lungs one way, and the bones the other a little bit....-- bs0u0155, May 21 2014 /Cudos" is either Latin for "mint", Lithuanian for "marvel" or Sao Paulo street-slang for "testicles"./
Or in my case, all three.-- bungston, May 21 2014 random, halfbakery