Thread: Integrity of water in space

What will happen to a ball of water (say, the mass of sputnik, ~100kg) in orbit?

We know that many comets are water. We know the space shuttle used to "atomize" and eject wastewater; the droplets froze and did not fizzle away into molecules. We know that an accidental icicle formed on the shuttle, did not boil off or sublime perceptibly, despite cycling through sun and shadow.

Am I right to assume my hypothetical ball would last just as long in orbit as most artificial satellites do?

I understand that liquid water in vacuum will violently boil, until the loss of vapor cools it to freezing. That's not really the question, and we can imagine this ball of water was pre-frozen at sea level before exposure to space.

I'm going to pose more interesting, related questions as the thread progresses.

:? Ball's still in my court. I'm trying to get a reality check here.


OK, next question:

We've got a ball 'o ice in orbit, about the size of a large igloo. An astronaut bores into it, and hollows out a little room. Plug the entrance, and pressurize the cavity with a hose or (daring) by breaking seal on spacesuit, inside.

Does the ball explode? Why didn't the spacesuit explode?

Our astronaut, now in pajamas, complains the room is too chilly. So another astronaut delivers a heater & battery, plugs that into some solar panels dangling off the ball.

Now the walls melt some don't they? And the ball must lose as much heat as is put into it. Is our astronaut about to die?

I'd imagine that ice does not have the toughness built into a space suit, and so would not survive being pressurised from within.

Comets - which do contain a lot of ice - are perfectly satisfactory for interstellar travel. They contain reaction mass for propulsion; water for consumption and farming; organics for food production. If I was a creationist I would be arguing that such a fortuitous combination of features smacks of intelligent design. 8)

@Ophiolite. You know where this is heading. Ball of liquid water, containing habitable air bubbles. Before we leap to habitation and travel, though, I want a better understanding of our construction material. From an engineer's perspective, and even a builder's perspective.

I arrived at the ball of water when challenged to design a self-sufficient orbital colony. "Just water" seemed more to the point (sustain life in space) than gee-whiz aerospace models of spaceships and elaborate steel structures. I reckon that if we simply amass water, and keep it liquid, nature will take care of most other problems.

In case anybody missed the jump, I'm proposing a ball of mostly liquid water, with large air bubble(s) in it, having a naturally frozen shell. This thread, I wanna learn how the shell works in space, or doesn't.

Originally Posted by sunshinewarrior

I'd imagine that ice does not have the toughness built into a space suit, and so would not survive being pressurised from within.

Doesn't this depend on the thickness of the ice? Atmosphere pressure is nothing like popular sci-fi, more like a very flat tire. But the problem is crucial. And even if my idea works in a vacuum, we still have the problem of stray nuts & bolts hitting it. Then what happens?

Suppose we make an ice composite with reinforcing fibre. That could be vegetable fibre - 15% wood pulp yields "pykrete" 3000psi compressive (like concrete) and better tensile than concrete. Or embedded wire & rebar as in reinforced concrete, over the top IMO and I see that as a cheat. I'd rather use pure water without any additives.

My first thought was to put the water in a bag. Like a spacesuit or some of our new ISS module designs. But the bag must be manufactured, it can't self-heal, it requires maintenance, it just seems like excessive packaging. Is that really necessary?

I want people to think about how they can kill this ice/water ball, and tell me how.

i do not think you could have ice in outer space. the pressure in outer space is 1.30471256x10^-16 atm and it has an averege tempature of 3 kelvin (-270) so if you were to look at a phase diagram of water you will see that it is in the vapor state. so even it you rased or lower the tempature it could never be a liquid or solid.

Originally Posted by unoscooter

i do not think you could have ice in outer space.

Well, there certainly is ice in space now. Plenty of it: Saturn's rings, asteroids, even moons of it. We've dumped water in orbit, and it forms ice.

Originally Posted by Pong

My first thought was to put the water in a bag. Like a spacesuit or some of our new ISS module designs. But the bag must be manufactured, it can't self-heal,

It can if you make it from living tissue bioengineered for the environment.

Originally Posted by Ophiolite

make it from living tissue bioengineered for the environment.

Then I'd have to crawl around out there painting on sunscreen and massaging my meatball with lotions wherever it got a little chapped. No thanks and I wanna keep to current technology and capability besides.

You're right though I do have an organic cell model... fairly well developed but just now I want substantial criticism of my first assumptions. So, try and sublime it, rupture it, erode it with solar wind, hit it with an asteroid...

Well, for one thing, fast moving debris or meteors might flash-boil the water if it hits at fast enough speeds. That should cause some serious problems, no?

We'd get a sudden pressure rise, somewhat more than water geysering out of the hole could relieve. Water isn't very compressible, and ice isn't very elastic. So, cracks all around? Then water's flowing into the cracks and boiling/cooling as it nears the surface? Pressure's dropping then. Ears pop - I'd rate that a failure.

The gaping impact hole. More pressure loss. The bends - catastrophic failure. How quickly does such a hole close up? Does it help if large solids can float into it and help clot it?

EDIT: Reconsidered this scenario. Since we already have a large core air bubble, that should absorb much pressure of impact and internal boiling. So we "just" have the gaping hole to worry about. The inertia of water is much greater than air, so volume loss is going to be relatively slow... I mean, compared to traditional space station designs with, say, a window blown out. Will near-freezing water around the sides flow in, boil, and plug the hole?

My heart isn't set on proving the model can stand that kind of abuse, but it's fun to imagine. I'm more keen to learn if the model is basically stable.

water in space at any emp is always going to be a gas. it can form ice or water when it comes into a higher pressure like on a planet or maybe even a comet.

Originally Posted by unoscooter

water in space at any emp is always going to be a gas.

Please take a reality check. I've given you examples, just Google them or better yet go to any of a hundred NASA pages matter-of-factly describing water ice in space at all pressures. Rings, tiny asteroids, water dumps in orbit, it's well documented and ought to be common knowledge after all these years.

Could I get an educated opinion on this please?

Hi Pong?

Since when does water boil and freeze in vacuum? This was a false statement you're letting of, absolutely.
And then, further, '...That's not really the question....' Your arrogance amazes me. Or am I missing your
point here?

Matter, not so water, does heat up when being compressed, meaning, the room matter does take in was
narrowed. To create a vacuum, air was evacuated providing more space for other matter, like water, to
expand it's volume.

And that was meaning, the room water would take in was not narrowed but extended. Your thread was
made of false arguments, right?

Steve

Originally Posted by Pong

Could I get an educated opinion on this please?

if you were to look at a high school chemistry book you will see that when dihydrogen monoxide (water) is at 3k and around 1x10^-16atm it will be in the form of a gas. so if you were to pour water into space it will boil and turn into a gas.

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Originally Posted by unoscooter

so if you were to pour water into space it will boil and turn into a gas.

Okay that's so in high school texts. And it makes good learning in a chemistry class. :?

But listen: we did already pour water into space from the space shuttles, for years, and we quit that why? Because A) the water (urine actually) would form icicles and block the nozzle, even a heated nozzle, and, B) bits of ice were hitting the shuttle - these little snowflakes were massive enough to be dangerous.

There's a NASA "urine dump" video somewhere out there. I've watched it and honestly the supposedly "atomized" spray looks more like snow than vapour.

The solar system naturally features plenty of ice. And the sizes range from microscopic to large moon. Hunks the size of sputnik are plentiful.

Anyway, I didn't start this thread to argue whether Saturn's rings exist or not.

This thread is about why and how, ice does exist in space. What are its properties?

That's what I often said. Space was still widely unknown to us. We need to distinguish space on the one hand and
the vacuum.

The observations you describe where made in space, where there are other effects on the water like the sun, or,
any normal surrounding conditions (temperature ) missing. Water freezes at 0°C and boils/evaporates at 100°
C. Also, there was no water in space known elsewhere then on earth, which gives it a status symbolizing some
normality for humans. as if we will try to transfer cultural data like freezing and boiling point to space, which was
not a good idea since we can not blur the view on what happened due to the fact space was not to explore by
conventional means, therefore it was no environment that could be survived exploring it (sensing space ) like
sensing the elements on earth.

So there are effects which are coming from other sources. It's not only about the vacuum. We all do know about
water floating freely in a space ship. There was not any magic happening to the water, which then was floating in
space, not in vacuum. In cold outer space regions it could freeze, as well as it could alter its state to becoming
a gas being closed to a source beaming heat. But, this was due to heat or the missing of heat, not due to vacuum,
I expose.

Here on earth, water exposed to vacuum will not boil and freeze afterwards, due to the vacuum. You firstly should
discharge such thinking. It was being plain wrong. Observable information do say something else.

ok under the sircumstances you have given it is imposible for dihydrogen monoxide to be in the form of gas. sence space has such a low presure the boiling point of water is lowered so it is not 100C anymore. it is so low that water could boil at 1000C or 100C or even 0C. so at any tempature water will boil and turn into a gas.

Originally Posted by Pong

I'm going to pose more interesting, related questions as the thread progresses.

*sigh*
This thread is a conveyor belt, the airplane cannot rise above.

Originally Posted by unoscooter

ok under the sircumstances you have given it is imposible for dihydrogen monoxide to be in the form of gas.

... first off, why do you feel the need to call it dihydrogen monoxide? water or h2o work fine. thats besides the point, yes ice can and does exist in space and can exist with little or no pressure, in fact being under no pressure would make the ice stronger...

comets are made out of ice and to my knowledge they do not have atmospheres and are in space, hence no pressure and 3 kelven. if you havent noticed, they are not made out of gas. i have the feeling im gonna get nowhere with this guy so ill just stop and get back to the topic....

europa's a good example of what your talking about, albeit larger. but remember its insides are kept liquid by tidal forces. anything like what your talking about would quickly freeze from the outside in without some source of heat...

haha i have the same feeling im not gonna get anywhere with you either...

Originally Posted by medlakeguy

in fact being under no pressure would make the ice stronger...

? Continue...

Originally Posted by medlakeguy

anything like what your talking about would quickly freeze from the outside in without some source of heat...

That's my understanding, roughly. However I think the loss of heat is wherever bubbles form, which should be throughout the volume. When we try a container of water - on Earth - with vacuum, bubbles form anywhere, and appear to form a bit more often near the surface. As for vacuum boiling a ball of water in space, nobody knows exactly how this will play out. Bubbles and boiling behave strangely without gravity (without buoyancy).

Originally Posted by medlakeguy

...without some source of heat...

That was my post #2. Suppose we have an ice ball, any type of ice ball so long as it's sturdy, then apply heat to the core with electric element or whatever. Some ice melts and becomes less dense, 'cause water's funny. So what's happening to the structural pressures of this ice ball as we add energy? Now it wants to implode? Can we gradually inject an Earth atmosphere (inside the water) to balance negative pressure of melting? Is this ball of ice and liquid water and air, stable for any useful span of time?

To add an atmosphere to a ball of water wouldn't work I guess.

Originally Posted by Steve Miller

To add an atmosphere to a ball of water wouldn't work I guess.

I agree. But if the water has an ice shell, stronger than a pop can, then what? Pressure at sea level is about 15psi, pressure inside a (room temperature) pop can is about 36psi. So our ice must be thicker than aluminum pop can, because ice is not so strong.

? Continue..

well, a little stronger. water's freezing point gets lower when its under pressure so ice in space would behave as ice would on earth if it was a few degrees colder at the same temperature.

However I think the loss of heat is wherever bubbles form, which should be throughout the volume.

as far as zero gravity boiling, i really have no idea. i get the feeling that in space and under no gravity the water might not "boil" in the sense we know, but just scatter (have a large amount of steam coming off it but no bubbles) any liquid doing this would get rid of heat very fast and you'd have an ice shell in no time... maybe, im just guessing here

Is this ball of ice and liquid water and air, stable for any useful span of time?

my guess is no, what about just a ball of ice? (i.e. comet) that's very stable, now imagine you drill down into it and build whatever facilities you need out of conventional materials like metal or plastic and keep it well insulated, waters there to be melted, solar powers available on the surface, you could stockpile food or grow it yourself with artificial light... do-able?

Originally Posted by medlakeguy

a little stronger

Something within the scope of this topic: there are many types of water ice. One type for every possible arrangement (or misarrangement) of the crystal lattice. Of course these have different properties. The naturally occurring space ice is mostly "amorphous ice" meaning that it doesn't have much or any grain to it - it's similar to liquid water, or glass. It's a bit denser than terrestrial ice but I imagine weaker because it isn't "fibrous" (?). Pure amorphous ice has the nifty quality of being clearer than glass. Of course after getting beat up by asteroids for a billion years it's not too glassy looking.

The model I'm looking at has crystalline (terrestrial type most likely) ice forming from cold water at standard atmosphere, and migrating very slowly to the surface as that surface is shed off by solar wind, impacts, and sublimation. So at least it begins as type number one, hexagonal (Ih). I've read that ice may change configuration, but if/how a stable lattice would break down to amorphous in space, I'm unsure about. Maybe sublimation followed by immediate deposition of those same molecules?

Originally Posted by medlakeguy

as far as zero gravity boiling, i really have no idea. i get the feeling that in space and under no gravity the water might not "boil" in the sense we know, but just scatter (have a large amount of steam coming off it but no bubbles) any liquid doing this would get rid of heat very fast and you'd have an ice shell in no time... maybe, im just guessing here

When we boil pressurized water without gravity, one large bubble forms at the source of heat, because there's no buoyancy to rise the bubble(s) "up". However our low pressure boiling has no source. I think your guess about what would happen to water suddenly exposed to space is a good one. Flash foam and the bulk of it frozen in an instant. Perhaps the consistency of a hard meringue?

Anyway, that scenario isn't likely, because any water we send to space would be cooled and depressurized much less quickly as it is mechanically unloaded to orbit. Or it would be pre-frozen prior to launch. Or it's ice harvested in vacuum already. So the question is ice in space, not water.

Originally Posted by medlakeguy

Is this ball of ice and liquid water and air, stable for any useful span of time?

my guess is no, what about just a ball of ice? (i.e. comet) that's very stable, now imagine you drill down into it and build whatever facilities you need

You just described a ball of ice and liquid water and air, stable for some useful span of time. Pretty well what I have in mind. Except that comet ice may be crummy stuff, structurally. So you must allow a much thicker shell... more mass to frozen shell means less to usable volume.

Originally Posted by medlakeguy

build whatever facilities you need out of conventional materials like metal or plastic and keep it well insulated

Insulation in space is a funny thing. Though space is technically very cold, it is also a fantastic insulator, being near-vacuum. Like a thermos. A space station (e.g. the International Space Station) accumulates heat in a big way, mainly by solar energy pumped in as electricity, that must ultimately resolve as heat. So the ISS has this circulatory cooling system and big radiators half the size of its solar panels to shed that heat. As for direct sunlight heating on the hull, simple white paint and really flimsy thin layers of insulation take care of that.

A colonized ball of ice would need to dump a load of heat too. Insulation between the ice shell and interior would actually help cook the residents. Radiators seem necessary. I think that if one dumped most heat that way, a modest heating could also conduct out through the shell and radiate off the surface. A little sublimation is tolerable and even helpful (more on this later) if one can take on water to replace that.

Originally Posted by medlakeguy

do-able?

I've got more sketched out, and I think it is. But we ought to try and prove the basic structure bad. If good, then proceed.

Evaporative annihilation. We know that little grains of ice around Jupiter and as near as the asteroid belt sustain sunlight for ...er, many... years without evaporating. What of Earth orbit? The fact that we don't have any natural ice around here suggests it doesn't last so long. On the other hand, we know that little flecks sprayed into orbit do survive as long as we've observed them. What I think is happening, is, the evaporation (by sunlight) removes so much heat, this more than compensates and so the speck does not heat enough to maintain a boil. It just loses surface molecules slowly. ? Then even a puny ice-sputnik should last longer in high orbit than anybody cares to reckon. ?

Originally Posted by Pong

Originally Posted by Steve Miller

To add an atmosphere to a ball of water wouldn't work I guess.

I agree. But if the water has an ice shell, stronger than a pop can, then what? Pressure at sea level is about 15psi, pressure inside a (room temperature) pop can is about 36psi. So our ice must be thicker than aluminum pop can, because ice is not so strong.

To do what? What are you aiming at? The thread was about the integrity of water in space, right?
Not about stem cell cloning.

Originally Posted by Steve Miller

To do what? What are you aiming at? The thread was about the integrity of water in space, right?
Not about stem cell cloning.

If I asked about the "integrity of clear acrylic in space", would you refuse to discuss that material as space station windows?

Add something useful, or don't comment.

Wait a moment,

Did I read Ophiolite's post correctly?

You know, I never thought of that idea before, Why doesn't NASA try to strap an unmanned satellite to a passing comet, then when it is farthest from our sun, launch it further into space?

That would sure as heck save a lot of fuel!

Later, if these unmanned satellites seem to fare well, we could somehow land a manned spaceship on the comet and launch off from it! It's like an inter-planetary bus route!

Originally Posted by SuperNatendo

somehow land a manned spaceship on the comet and launch off from it! It's like an inter-planetary bus route!

Except the bus doesn't stop, so you've got to run at bus speed to board... no fuel saving that way, in frictionless space. BUT if there was a pop machine aboard the bus and you were thirsty it might be worth riding. AND if it were raining cosmic radiation you might wish to save your gonads behind a few tons of ice hull.

Comets are a good source of water, and, I think, easily refined and molded construction material. Melt the interior and latent spin should separate the water, crud, and valuable traces. Cast it into Lego blocks or just a big purified sphere 'o goodness.

Originally Posted by Pong

Add something useful, or don't comment.

Sure. This seemingly was your last clue always. To be talking to a mirror. An other thought, you can not
draw information from this thread without giving, here or an other place, now, prior or later on. An other
lesson you still need to learn.

So check on your attitude and keep on trying to behave like a human being.

Originally Posted by Steve Miller

Originally Posted by Pong

Add something useful, or don't comment.

Sure. This seemingly was your last clue always. To be talking to a mirror. An other thought, you can not
draw information from this thread without giving, here or an other place, now, prior or later on. An other
lesson you still need to learn.

So check on your attitude and keep on trying to behave like a human being.

settle down there betsey

You just described a ball of ice and liquid water and air, stable for some useful span of time. Pretty well what I have in mind. Except that comet ice may be crummy stuff, structurally. So you must allow a much thicker shell... more mass to frozen shell means less to usable volume.

well yes and no, i was thinking about maybe inhabiting some man made caverns on a comet, in this case the crummy structure might actually be helpful in that it would be easier to drill and build with.

just drill down about 20 meters and hollow out whatever space you need.

like i was saying before youd probably need to line your cave with some other material as ice doesn't make a good foundation for much of anything. you'd have to keep it well insulated so your climate controlled cave dosent melt the ice and methane surrounding it and fall apart

i guess the only problem with this design would be that the comet would have to be pretty far out there as it would be very unstable in the inner solar system... pure ice would be more stable, but now that you mention it sublimation would be a big problem. just look at how much material comes off any comet this side of the asteroid belt...

it'd defiantly need to have a shell of some kind...

Originally Posted by medlakeguy

Originally Posted by Steve Miller

Originally Posted by Pong

Add something useful, or don't comment.

Sure. This seemingly was your last clue always. To be talking to a mirror. An other thought, you can not
draw information from this thread without giving, here or an other place, now, prior or later on. An other
lesson you still need to learn.

So check on your attitude and keep on trying to behave like a human being.

settle down there betsey

Well, you'll think about your comment when you will be in need for my help.

Good bye!

Steve

Originally Posted by Steve Miller

Originally Posted by medlakeguy

Originally Posted by Steve Miller

Originally Posted by Pong

Add something useful, or don't comment.

Sure. This seemingly was your last clue always. To be talking to a mirror. An other thought, you can not
draw information from this thread without giving, here or an other place, now, prior or later on. An other
lesson you still need to learn.

So check on your attitude and keep on trying to behave like a human being.

settle down there betsey

Well, you'll think about your comment when you will be in need for my help.

Good bye!

Steve

haha ok then

Originally Posted by medlakeguy

just drill down about 20 meters and hollow out whatever space you need.

...pure ice would be more stable...

I guess one good way to hollow a comet would be to melt the interior (say, with mirrors) and pump water out. What to do with all the water/ice we extract? Why not use that, instead of the comet? If you're going to bring the appropriate tools anyway.

Hm... the heat drill & pump setup could be modified for steam propulsion? Then purify AND reposition the water (to Earth), all without bringing any fuel to speak of?


Some very showy material does come off comets near the sun, true. And these are "dirty" snowballs, so much of the exposed surface must be rocks that unlike the ice "binder" don't evaporate. On the other hand, these comets approach closer than Earth and have done so millions of times.

I'll grant that sublimation should be minimized.

So you reckon ice near Earth needs protection from sunlight or it'll evaporate too quickly? Then either shrouding it with insulation, keeping it in shadow, or otherwise restricting sunlight is necessary. I don't suppose that's much to ask. Sputnik-sized, we could drape a garbage bag around it - not any cheap old black garbage bag, but a modern white garbage bag. Or, more durable, random weave fibreglass matting, not unlike the fuzz that certain cacti grow for shading. Just enough to reduce sunlight, comparable to asteroid belt or Jupiter. How's that?

Originally Posted by medlakeguy

ice doesn't make a good foundation for much of anything

We don't need a foundation where there's no gravity. For example, you can float a pup tent, in an air bubble, in a water blob, in a comet. These things just don't move around of their own volition. Some light cordage could keep everything in place, with people yanking around. The air gap I think answers your wish for insulation.

Can you tell I hate the idea of hauling any more mass off Earth than is absolutely necessary?

Originally Posted by medlakeguy

Originally Posted by Steve Miller

Originally Posted by medlakeguy

Originally Posted by Steve Miller

Originally Posted by Pong

Add something useful, or don't comment.

Sure. This seemingly was your last clue always. To be talking to a mirror. An other thought, you can not
draw information from this thread without giving, here or an other place, now, prior or later on. An other
lesson you still need to learn.

So check on your attitude and keep on trying to behave like a human being.

settle down there betsey

Well, you'll think about your comment when you will be in need for my help.

Good bye!

Steve

haha ok then

Thumb up!

A spacewalk accident provides more information. What happened, was, an astronaut got cut through his suit. He didn't notice at the time. Later they found blood had flowed into the gash and froze tight, so the suit maintained pressure.


I'd love to see some experiments done with water in space station airlock.

Originally Posted by Pong

A spacewalk accident provides more information. What happened, was, an astronaut got cut through his suit. He didn't notice at the time. Later they found blood had flowed into the gash and froze tight, so the suit maintained pressure.

Was this true? The compression must have been very low. From which source did you get it?

This sounds more like the incident that befell Captain Joseph Kittinger when he stepped out a the gondola of a balloon at 102,800 feet for the longest free fall flight to date. One of his suit wrist connectors was loose. His hand swelled up and sealed the leak.
A quick google reveals that we are nearing the 48th anniversary of his jump - August 16th.

Originally Posted by Ophiolite

This sounds more like the incident that befell Captain Joseph Kittinger when he stepped out a the gondola of a balloon at 102,800 feet for the longest free fall flight to date. One of his suit wrist connectors was loose. His hand swelled up and sealed the leak.
A quick google reveals that we are nearing the 48th anniversary of his jump - August 16th.

Wow, that's genuine!

Originally Posted by Steve Miller

Originally Posted by Pong

A spacewalk accident provides more information. What happened, was, an astronaut got cut through his suit. He didn't notice at the time. Later they found blood had flowed into the gash and froze tight, so the suit maintained pressure.

Was this true? The compression must have been very low. From which source did you get it?

This page. But I've learned it was a puncture (not cut as I said) from small rod stuck into the astronaut's flesh which may have stayed put throughout the walk. It's unclear if frozen blood was helping to seal the hole.

I'd love to see some airlock experiments with bags of water, punctured bags, etc.

The astronauts suits are being made of several layers, right? They seem to have sharp edges up there!

Originally Posted by unoscooter

i do not think you could have ice in outer space. the pressure in outer space is 1.30471256x10^-16 atm and it has an averege tempature of 3 kelvin (-270) so if you were to look at a phase diagram of water you will see that it is in the vapor state. so even it you rased or lower the tempature it could never be a liquid or solid.

You're forgetting that you can't apply the normal rules because frozen water is a crystal. It doesn't behave like ordinary solids because part of its solid-ness comes from the odd kinds of chemical bonds between the oxygen and hydrogen.

Originally Posted by Pong

:? Ball's still in my court. I'm trying to get a reality check here.


OK, next question:

We've got a ball 'o ice in orbit, about the size of a large igloo. An astronaut bores into it, and hollows out a little room. Plug the entrance, and pressurize the cavity with a hose or (daring) by breaking seal on spacesuit, inside.

Does the ball explode? Why didn't the spacesuit explode?

Our astronaut, now in pajamas, complains the room is too chilly. So another astronaut delivers a heater & battery, plugs that into some solar panels dangling off the ball.

Now the walls melt some don't they? And the ball must lose as much heat as is put into it. Is our astronaut about to die?

Here the question is how much heat is that ice ball losing per hour to the space around it? If it's a little, then we won't want to get it too warm in there. If it's a lot, then you're going to need one very very powerful heater to keep it warm in there.

Of course, you can always adjust the relative size of the ice ball to the chamber until you get a proper fit.

If it's like a space station containing human activity (lights, motors, warm blooded animals) then it needs cooling not heating. Even space suits have big radiators on the back. Technically space is very cold but it is also a near-perfect insulator.

How to regulate?

If temperature increases, internal ice melts resulting in pressure drop.

I would like to add ecology to stabilize things. For example increased internal air pressure (from too cold) would enrich water, so more aquatic plants, so more organic heat. That kinda thing has worked before. :wink:

Hi Pong!

Typed nicely, but wrong trace. Anyway.

Steve

Originally Posted by Pong

If it's like a space station containing human activity (lights, motors, warm blooded animals) then it needs cooling not heating. Even space suits have big radiators on the back. Technically space is very cold but it is also a near-perfect insulator.

How to regulate?

If temperature increases, internal ice melts resulting in pressure drop.

I would like to add ecology to stabilize things. For example increased internal air pressure (from too cold) would enrich water, so more aquatic plants, so more organic heat. That kinda thing has worked before. :wink: