Boeing Starliner Capsule "Trapped in Space"?

[Erie Fred]

The beancounters are assuming the 2 people are robots, that continue as normal.
Typical BoingBoing management, everything is a chart.

One of them get's sick, all bet's are off.
jettison the body maybe as it's cheaper, and then try to carry on as normal ?

 

[Morrisman]

I hope they had plenty of time left on their passports.

It'll be a bit of a bummer if they get sent back by border control because their passports have run out while they're up there.

Nobody gets sent back by Border Patrol, not in the UK anyway, they’re invited in with open arms, that much we’re all aware of.

 

[Robotstar5]

Nobody gets sent back by Border Patrol, not in the UK anyway, they’re invited in with open arms, that much we’re all aware of.

Landing a Starliner in Hyde Park would certainly throw the border patrol, they're used to dealing with large rubber dinghies on the beach

 

[Screwdriver]

Landing a Starliner in Hyde Park would certainly throw the border patrol, they're used to dealing with large rubber dinghies on the beach

They could do that, the Starliner crew module is designed for a hard landing (!) on solid earth.

Parachutes deploy (one hopes) and at the last moment, six big bouncy balls cushion the landing.

They do this so it can be reused but typically in areas of low population so that they can reconfigure the trajectory for a destructive reenty. Let's hope they don't have to make that call!

 

[voipio]

But I was taught that it is impossible to destroy matter just change it . If correct what into and where.

If wet clothes at room temperature, or thereabouts, were jettisoned into space, the water associated with them would boil, resulting in a lowering of the water temperature (think heat of vapourisation), until it reached 0degC, at which point any residual water in the clothing would freeze. The boiling would stop, and the remaining ice would gradually be lost by sublimation. This could take minutes to hours, depending on things like heat present from sunlight, the spacecraft's, and the earth's black body radiation, impinging on the clothes. In deep space, the clothes would cool down to the temperature of their surroundings i.e. the "black body" temperature of deep space, considerably slowing the rate of sublimation of the water ice (think comets surviving as water ice bodies for millions of years). During all of these stages, the water would remain intact as water molecules, either liquid, solid, or gas, unless it was hit by energetic particles, or interacted, and was able to react with, other substances.

 

[Screwdriver]

No I don't think that is correct. Certainly you can forget about water forming a solid at 0ºC in a vacuum. It think it's closer to -50º - 70º.

The tricky part in this thought experiment is the water being so spread out in wet cloth which will behave differently from a large mass of water say in a cup. If a sample is exposed to the near perfect vacuum of space, then all of the water will instantaneously be above its boiling point..

In a cup of water despite it literally boiling, it might also freeze due to the effect you mention above causing the temperature to quickly fall well below the temperature it would otherwise sublimate. This is theoretically due to the large volume allowing for cooling to occur more quickly than evaporation or sublimation. Once it has formed solid ice (or compacted snow!) so long as it is not exposed to a source of heat, It can happily sit there like, say, a comet.

For a smaller, less dense volume of water in clothing or the liquid in our bodies, that does not apply. All of the water/liquid will boil and will not be cooled by the latent heat of evaporation but instead crystallise and sublimate.

At least that's the impression I get. Having waded through a number of websites there does not appear to be a consistent story and perhaps surprisingly, no evidence for any experiment having been made...

Anyhow, it's definitely not 0ºC, that only works at STP and is not a fixed property of water.

 

[voipio]

If aqueous samples in test tubes are observed going through a freeze drying process, under vacuum, it it possible to see the water boil, as the pressure is reduced below atmospheric and, in doing so, the sample temperature falls until eventually the solution freezes, and stays at 0degC whilst it slowly reduces in volume, taking heat from the surroundings, until all that is left is the powdery residue of the solute that was in the sample. Water freezes at 0degC at normal atmospheric pressure, and the freezing point temperature changes very little, actually increasing very slightly (to about +0.01degC), as the pressure is reduced, all the way down to a good vacuum. The freezing point of water decreases under increasing pressure, reaching about -0.1degC at 10 Bar and -8.9degC at 1000 Bar, and this is why ice skating is possible, provided that the ice temperature is not too low.

The sublimation rate of water from a frozen surface is highly temperature-dependent, being relatively rapid when the ice temperature is close to the freezing point, and decreasing almost to zero in the coldness of deep space. At around -20degC (i.e. freezer temperature) it is possible to see the effects of sublimation, by way of ice crystals in sealed packs of food.

The body is somewhat different to wet clothing in space. The saturation pressure of water at 37degC is about 0.9 psi, similar to the pressure required to inflate a balloon so, provided the "bag" of tissues that effectively form the "body containment vessel" can withstand this pressure (the body doesn't explode when blowing up a balloon), then the fluids contained within the body wouldn't boil away in a vacuum, apart from the moisture in exposed mucous membranes. Apollo capsule pressure was 5 psi absolute whilst in orbit, with the astronauts breathing pure oxygen, in order to maintain blood oxygenation levels. It should be possible to go down to 3 psia in pure oxygen, and survive, but be quite uncomfortable, due to water evaporation from exposed mucous membranes. I'm pretty sure that NASA would have done the necessary testing.

 

[Screwdriver]

I don't think we disagree that much tbh. The subject is highly influenced by the exact scenario, for example with the volume of water and how it is contained having such a dramatic effect on the outcome. That is particularly true for whether or not water in a vacuum will freeze at 0ºC which is almost a non sequitur since it is such an artificial circumstance anyway. I did try to find some definitive answers but I got as many different answers as I asked questions.

I am happy to defer to your superior knowledge since I have very little practical experience and no formal training. I do find the subject quite fascinating though especially since water exhibits quite extraordinary properties under a variety of circumstances.

 

[Misterg]

I did try to find some definitive answers but I got as many different answers as I asked questions.

What you need is the phase diagram for water - it shows what state it will be in at different temperatures and pressures. Only at very high pressures is it still a liquid below (roughly) 0°C - the red bit on the diagram.

So when they hang the washing out on the ISS, they start with liquid water at 25°C / 1 atmosphere (in the green bit).

Reduce the pressure (i.e. move vertically down the chart) until you hit the dividing line between liquid and vapour - this is where it will boil.

As the liquid turns to vapour (boils) it will lose energy (latent heat of vapourisation) so its temperature will drop. If you keep reducing the pressure the conditions in the remaining water will track along the border of the vapour phase (the brown bit) until below the Triple Point when the remaining liquid water will freeze. (It will freeze at +0.01°C, so a slightly warmer than at atmospheric pressure.)

Keep reducing the pressure, and the conditions will keep tracking the border of the vapour phase for as long as there is some ice left. At really low pressures, you will have solid ice at about -60°C which, in the absence of external energy, will just sit there. If there is external energy (sun shining on it, etc.) the ice will sublime straight to vapour.

 

[Morrisman]

Damn, but there’s some clever people on this forum.

 

[Greeves246]

Washing. So that’s why there was a woman on the crew. But can she do ironing in zero gravity? Seriously, on these long term flights to Mars, if there was a pregnancy would childbirth be a problem in space?

 

[Screwdriver]

What you need is the phase diagram for water - it shows what state it will be in at different temperatures and pressures. Only at very high pressures is it still a liquid below (roughly) 0°C - the red bit on the diagram.

Yes I am familiar with the phase diagram. However it represents a static snapshot of classic behaviour, not how the properties vary over time. Also according to that diagram, the freezing point for water is -50ºC at 1Pa and while you can trace a line "straight down" from 0ºC from STP, in our thought experiment, the water is instantaneously exposed to a vacuum. The -50ºC freezing point keeps popping up in answers for "what is the freezing point for water in a vacuum".

The behaviour appears to vary hugely depending on the volume of water and the container its in. That's why I am still of the opinion that it cannot be said to be 0ºC but an opinion is of no merit if there is no hard science to back it up.

What is VERY interesting of course is the vast number of "types" for this "simple" substance. I did write an article once on the properties of thalassogens inspired by Isaac Asimov. I'll see if I can dig it out if anyone is interested.

 

[voipio]

What you need is the phase diagram for water - it shows what state it will be in at different temperatures and pressures. Only at very high pressures is it still a liquid below (roughly) 0°C - the red bit on the diagram.

View attachment 460319
So when they hang the washing out on the ISS, they start with liquid water at 25°C / 1 atmosphere (in the green bit).

Reduce the pressure (i.e. move vertically down the chart) until you hit the dividing line between liquid and vapour - this is where it will boil.

As the liquid turns to vapour (boils) it will lose energy (latent heat of vapourisation) so its temperature will drop. If you keep reducing the pressure the conditions in the remaining water will track along the border of the vapour phase (the brown bit) until below the Triple Point when the remaining liquid water will freeze. (It will freeze at +0.01°C, so a slightly warmer than at atmospheric pressure.)

Keep reducing the pressure, and the conditions will keep tracking the border of the vapour phase for as long as there is some ice left. At really low pressures, you will have solid ice at about -60°C which, in the absence of external energy, will just sit there. If there is external energy (sun shining on it, etc.) the ice will sublime straight to vapour.

I like that explanation. Just worth noting that the ice temperature, below the Triple point, won't immediately decrease to the new value shown in the chart, as the pressure drops further. The phase diagram represents equilibrium conditions, and lowering the pressure will "upset the equilibrium", favouring sublimation. The heat of sublimation is numerically similar to the heat of vapourisation, so the ice cools as sublimation proceeds, but the rate of sublimation is (much) slower than boiling, so the rate of ice temperature's fall will be correspondingly slower.

 

[Misterg]

The -50ºC freezing point keeps popping up in answers for "what is the freezing point for water in a vacuum".

That doesn't mean it's correct, though.

 

[8ob]

The capsule was launched with two astronauts on board on June 5th and meant to return on the 13th June. That was scrubbed as was one one later scheduled return and they have now put the date back in to July. The problem is that a number of leaks have occurred in the helium gas system which is used to push propellants out of their tanks and to a number of small rocket thrusters which control the movement of the capsule. For a safe re-entry, the capsule will need to to be very accurately positioned and orientated, so thrusters falling off-line could be catastrophic.

Apparently, there is already consideration of using one of Elon's SpaceX capsules to bring the crew back. https://www.bbc.co.uk/news/articles/c6pp29gdwe6o
Tough times at Boeing

That poor guy is trapped in there with a very aesthetically challenged she , only one way of escaping

Bob

 

[voipio]

That doesn't mean it's correct, though.

The -50degC figure is the temperature at which water vapour, at a pressure of ~5Pa, tends to turn to solid. It's not strictly freezing, which is conventionally the transition from liquid to solid. Rather, it's more akin to vapour deposition, or condensation of matter, or just condensation, really, just straight to solid.

Note also that, although the phase diagram in post #89 stops at 1Pa and -60degC, the solid/vapour transition line will continue downwards, and leftwards, as the pressure drops still further.

 

[Screwdriver]

That doesn't mean it's correct, though.

I know right, as @voipio points out above, the various properties interact over time so without empirical evidence, it's as much a guess as anything.

Even the question "at what temperature does water freeze in a vacuum" is flawed without really going into detail on the exact starting conditions.

I wonder if it might be possible to ask this question of the ISS crew - "what happens to your washing if you hang it up outside on a space washing line".

I bet it stinks like a chicken coup in there now...

 

[voipio]

Not forgetting that super pure water can exist in a supercooled state, until something starts off the process of formation of the solid state, at which point it's temperature rapidly ramps up towards 0degC, through the release of the latent heat of solidification.

 

[Screwdriver]

Not forgetting that super pure water can exist in a supercooled state, until something starts off the process of formation of the solid state, at which point it's temperature rapidly ramps up towards 0degC, through the release of the latent heat of solidification.

"Alloys" of water behave in ways not dissimilar to that of metals in that the merest whiff of some contaminant and its physical properties change radically.

If nothing else, it reminds us that while we have discovered much about our universe, there is a heck of a lot more out there yet to be found.

 

[Robotstar5]

Washing. So that’s why there was a woman on the crew. But can she do ironing in zero gravity? Seriously, on these long term flights to Mars, if there was a pregnancy would childbirth be a problem in space?

All part of the training