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Has an astronaut (or cosmonaut) taken water out of a spacecraft to see if it boils or freezes?

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    $\begingroup$ You have answers to whether or not someone has done it. On a theoretical note, I will claim that It will freeze and boil simultaneously. Space is cold, but it doesn't itransfer heat very well so the liquid cannot freeze unless it simultaneously boils. It sounds crazy but there it is. It will boil, lowering it's temperature, it will freeze, increasing it's temperature, and keep on untill it is a haze of snow and ice. The boiled water won't go far, it will sublimate to ice/snow pretty much immediately. $\endgroup$ – Stian Yttervik Jan 27 at 13:50
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    $\begingroup$ While its not "outside of a spacecraft" in the sense I imagine you mean, this is a good video about water in a vacuum (or at least very low pressure). $\endgroup$ – Richard Ward Jan 27 at 14:45
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    $\begingroup$ No astronaut did this, it was known before that liquid water exposed to a vacuum would be partially boil and evaporate and partially freeze to ice. The ice would then sublimate, that is going from solid ice to water vapor directly without a liquid state in between. This may done using a good vacuum chamber on Earth. No need to waste precious weight of payload and time of an astronaut in a spacecraft to repeat an experiment already done. $\endgroup$ – Uwe Jan 27 at 21:50
  • $\begingroup$ See this Forbes article: water Will first boil violently and then cristalize to solide ice. $\endgroup$ – agtoever Jan 28 at 10:31
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I do not know of any time water was brought out of a spacecraft, but the astronauts regularly had to do a urine dump into outer space. Astronaut Mike Massimino talks about watching the urine freeze. He said they would all watch it, as it was something beautiful to see.

Here are some images of the frozen pee entering the Earth's atmosphere, as seen from the ground Space Shuttle Unleashes Magnificent Plume of Pee.

Pee (waste water) tossed into outer space by astronaut Kevin Ford, as photographed from Hungary

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    $\begingroup$ The Apollo fuel cells generated more water than the spacecraft needed, so the astronauts would periodically dump the excess overboard. It reportedly behaved much the same as the pee dumps. $\endgroup$ – Mark Jan 28 at 21:05
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The shuttle dumped both waste - and when not taking it to the International Space Station - excess potable water generated by the fuel cells.

Since this Hubble mission, STS-125, did not go to the space station, they had to dump both kinds of water. Here is a video taken from payload bay camera A. At about the 4 minute mark it's really streaming out.

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    $\begingroup$ Do the engineers need to take the propulsion effect into account for navigation? It looks like a propulsion engine of some sort to my non-savy eyes. $\endgroup$ – Pac0 Jan 27 at 22:53
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    $\begingroup$ @Pac0 The Apollo missions had to tell mission control when they emptied urine for this exact reason. During the Apollo 13 return the astronauts were explicitly ordered not to dump their... dump. "The ground, anxious not to disturb our homeward trajectory, told us not to dump any waste material overboard. What to do with urine taxed our ingenuity." from history.nasa.gov/SP-350/ch-13-5.html $\endgroup$ – Arthur Jan 28 at 15:28
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Bob516 has answered the question of what happens to water in space, but directly answering your question it would be highly dangerous to take a floating ball of water into an airlock and watch it as you cycle out as the first stage uses a scavenger pump to recapture as much air as possible, and the final stage involves valves that vent the rest of the pressure in a controlled fashion.

The floating ball of liquid water would tend to be sucked into both these systems and neither are something you want liquid water freezing and/or boiling inside since this will tend to rupture/block pipework you need to either finish exiting or get back inside.

So you would most likely not be able to see the water by the time pressure is low enough for things to happen, and then have to work out how to fix your airlock from inside.

For really large scale water in space there is project highwater

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    $\begingroup$ This answer only seems correct if you assume a "floating ball of liquid water", which wasn't part of the OP's question. It seems reasonable to assume instead that the water can be brought out in a sealed container and then released. $\endgroup$ – JBentley Jan 27 at 17:51
  • $\begingroup$ @JBentley I wonder what kind of container would be needed. At 20C the vapor pressure of water is only 0.023 bar, so a zip-lock bag might or might not be strong enough to maintain sufficient pressure to keep it from boiling and popping open. $\endgroup$ – uhoh Jan 28 at 1:16
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    $\begingroup$ @Uhoh - proves nothing but just vacuum bagged a ziplock bag of 90% water inside a jar and it stayed sealed. Believe the sealer pulls down to about 15% of one atmosphere. Was dead certain it was going to burst everywhere but seems ziplock bags are tougher than I thought. Would still not want to share an airlock with one (or have a ziplock space suit!) but looks like a reasonably tough bag and a sharp edge would do the job from the purely practical perspective. $\endgroup$ – GremlinWranger Jan 28 at 2:08
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    $\begingroup$ @GremlinWranger that's fantastic!! I don't know on which SE site I can ask "how strong are ziplock bag seals?" in order to provide you a venue to post a photo and materials and methods section. Thanks for the info and initiative! $\endgroup$ – uhoh Jan 28 at 2:13
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    $\begingroup$ @uhoh Would really want a proper vacuum gauge do post as more than a comment but had always been curious after seeing mention of the Soyuz suits having a twist and tie seal and the Space shuttle escape bubbles having a zipper. When it comes down to it, one atmosphere is not that much as long is the area it applies over is small relative to the structure of the seal but was cool to see for myself. $\endgroup$ – GremlinWranger Jan 28 at 2:22
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The Apollo astronauts on the Moon took water out of their spacecraft the Lunar Module. It was enclosed in their backpacks and was used to cool the astronauts by removing excess heat in a sublimation cooling plate. It was a porous plate, one side exposed to the lunar vacuum, the other side was part of the cooling water loop.

Liquid water filled the pores and evaporated to the vacuum removing heat and causing the remaining water in the pores to freeze and block the pores. The water ice then sublimates (going directly from solid ice to gaseous water vapor) removing additional heat. If the ice in a pore is fully sublimated, the pore is filled with liquid water again and the process repeats.

The sublimation cooling plate was a critical and essential part of the suit life support system. As every other part of the suit, it was tested very thoroughly on Earth in vacuum test chambers.

The astronauts did know very well before launch what happens to the cooling water in their suits and backpacks. No need to do any experiments with water on the moon anymore. They could rely on the functionality of the cooling system.

But water was used to cool also the Lunar Module and the Command/Service Module in a similar way.

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Water at room temperature will boil when exposed to low pressure. This can be seen in experiments on Earth:

Boiling water at room temperature in a vacuum chamber.

Whether the water freezes before it all boils off will depend on the quantity of water. Very small droplets (such as the jettisoned urine mentioned in the other answers) will cool faster, and therefore freeze faster, than a big bucket of water. Also, formation of ice is enhanced by having a place to nucleate the ice crystals. So whether the water makes contact with ice crystals or another suitable surface for nucleation will determine how fast it freezes:

Supercooled liquid water freezing on contact with ice.

At low enough pressure (in space!), water is guaranteed to eventually boil or freeze, since liquid water is not stable at low pressures.

This phase diagram shows that the liquid state is not stable below 611.657 Pa of pressure, irrespective of the temperature. After the water freezes in space, it will evaporate (sublime) directly from the solid phase to the gas phase.

enter image description here

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It would be an interesting experiment for a space-walking astronaut to take a water-filled balloon outside.

If you consider the sequence events:

  1. As he either passed through an airlock (or depressurised a capsule in prep for exit), the balloon - filled only with water - would expand somewhat as the pressure fell to zero;

  2. But, if we imagine here a balloon material strong enough not to split, the water would, as the pressure headed for zero, move towards.. boiling;

  3. But, at the same moment if exiting the craft, the temperature experienced by the ballon would drop to an extremely low level - which should freeze the water fairly rapidly into a solid sphere.

It would be interesting dynamics to see which effect dominated: presumably, all down to the timing of exit, the rapidity of pressure drop alongside the rapidity of temperature fall.

Quite possibly the water - containing the dissolved gases of the capsule air - would partially 'boil' internally, momentarily - but while remaining cold, remember, and purely due to the pressure drop - so air bubbles would form, as in a boiling kettle, before the temperature drop took over and froze the liquid to solid.

I would guess you would get a 'cloudy' ball of ice, full of trapped air bubbles.

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  • $\begingroup$ The water needs to boil under very low pressure to cool down and freeze partially. The other part is the exhausting water vapor.. The water vapor will remove heat, not the pressure drop itself. The ballon experiences no temperature in a vacuum as there is no heat transport by gas movement. Only heat transport by radiation or veaporation is possible. $\endgroup$ – Uwe Jan 28 at 9:53

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