What if I exposed only my hand to outer-space

I made this thread about if something has died yet on space and it made me wonder, with the pressure difference, the unprotected skin and sunlight and so on; what if I have a space suit designed in such a fashion that my hand is the only bodypart that is unprotected while the rest of my body is adequatly protected.

What can happen to my hand? what if I make a slight cut on my finger? will the vacuum suck out all my blood? What happens if I touch the exterior of the spaceship - if its really hot or cold will it have the same effect as if I touched something really hot or cold on earth?

Also, what if it was my head that was exposed, except for my mouth and nose would be protected and supplied with oxygen; and if I had something to cover my ears. would my eyes burst? or the moisture of my eyes would go out? also, would sunglasses improve my situation at all?:cool:


It would depend on how quickly your hand was exposed to space. If it was sudden, then you have explosive decompression, and if you had a cut, then any dissolved gasses in your bloodstream (oxygen for example) will boil out and dissipate into space. This could be bad for your bloodstream I would imagine, though I’m not sure about the specifics. Likewise, solar radiation on direct skin could give you a sunburn pretty quick, if not ‘microwaving’ your hand nearly instantaneously :confused:

Many other posters have mentioned the ‘instant freeze’ effect doesn’t really happen because in a vacuum temperatures remain fairly constant, however in the instance of explosive decompression you can have a very rapid temperature drop (just look at how cold gas is when escaping out of a pressurized tank)

The closest real life incident approaching the OP is Joseph Kittinger’s (still standing) freefall record. Even a partial pressure leak with a glove on at not-quite-near-space created a seriously painful injury.

(How this guy lived thru all he did is amazing.)

Can you please back up the explosive decompression bit. There is only 14psi difference from in the suit and out. That’s about equal to 32 feet under water. I can swim straight to the surface from 32 feet under water if needed. There would be no explosive decompression provided my mouth was open.

For the OP, IANA astronaught(nor can I spell it) and IANA doctor but I’m gonna go with brusing of the hand, like a giant hicky at first, then swelling as fuilds are drawn into the soft parts of the hand. Continued exposure causing rupture of the skin over time as the fluids build up. Freezing cold temps as the moisture boiled off through your skin. Cracking of skin as it froze. Eventually, uncontrolled bleeding as the arteries became exposed to the vacuum, forearm bones eventually being ejected from the now open wound where your hand used to be, followed by the contents of your arm, expulsion of your lungs and heart, collapse of your chest cavity, with your brian sucked through the base of your skull into your now empty chest cavity with the fluids and organs of your abdomin eventually forcing your brains out through your arm so that only your sunken in head, deflated chest and legs remained in the suit.

No??? well maybe not, but I’m pretty comfortable up to the part of cracking of the skin as it freezes and maybe lots of bleeding.

Just a note.

But the current space shuttle eva suit has a pressure of 4.3psi and I belive the apollo suits were about 3.9 psi, pure oxygen, with low enough pressure to be flexible.

No suit would be 14psi as you would be resemble a totally rigid michelin man!

For a bit more info on Kittingers hand see http://www.sff.net/people/geoffrey.landis/vacuum.html

*Originally posted by bunyip *
**the current space shuttle eva suit has a pressure of 4.3psi


In that case, maybe the freezing starts before the swelling. I think 4.3PSI may still be able to give you a hicky.


The atmospheric pressure on top of mount Everest is only about a third of sea level, say 4.9psi.

When you wear a space suit or climb Everest its the partial pressure of Oxygen that matters.

Breathe 100% oxygen as in a shuttle emu suit and 4.3 psi is fine (with pre breathing and lowered cabin pressure to prevent the bends)

The Russian Orlan-M suit has a pressure of 5.7 psi and the improved Nasa markIII suit has a pressure of 8.3.(higher pressure due to rigid suit components)

originally posted by billy

That’s really funny, but I don’t know why. Astronaught is Latin for star nothing. It’s -naut. Was that a bad pun directed at NASA?

For the record, I have absolutely nothing to contribute. I’m just here to listen and throw smart-aleck barbs.

hmmm…my brain would exit my body through my arm hey…that could cause permanant damage…not good…
I have my doubts about microwaving my hand though, I don’t understand why in outer-space you would only become cold really slowly but become really hot really fast…

Anyone has more details on the boiling under my skin? what would happen to my boiling blood when it re-enters the pressurised part of my body?

I can swim straight to the surface from 32 feet under water if needed. There would be no explosive decompression provided my mouth was open

There would,however be an explosion in your lungs if you were to hold your breath. So simply keeping your mouth open in addition to breathing normally is in order. It’s called Lung Expansion Injury.

Swimming up to the surface isn’t an analogous situation. When you are in water, there is an even pressure on your body. Basically your body is like a plastic bag filled with water. If you bring the bag to the surface it doesn’t expand, so the bag doesn’t burst. At all times there is an even pressure on the bag which is matched by the pressure inside the bag.

But if you get a powerful vacuum cleaner and put the vacuum cleaner hose right onto the plastic bag, there is now a force on the skin. There is an even pressure on the rest of the bag, but less pressure at the hose. So the plastic will break and all the water will leak out into the vacuum cleaner. This is the same situation as if you thrust a hand out of a spacesuit. In a way, it’s a worse situation than if you jumped out of the airlock - at least there will be no differential pressure on your skin. (Breathing would be a problem though.)

That said, I’m not sure if 14 psi differential pressure is enough to break the skin. But if the skin does break, the pressure differential will push all your blood out through that hole.

Yes, and you can probably figure out from my post I am aware of this and hence, my disclaimer. And it’s not breathing normally if I’m rushing to the surface, most likely I can only exhale. I mean, why rush to the surface if I can breath where I am? But now we’re both splitting hairs don’t you think?

That’s a fine analogy but I thought my description of the brains being pushed out the arm by the guts was more colorful. It’s the same effect as some boring old water being sucked out a bag by a vacuum cleaner, and the OP wasn’t asking about vacuuming water bags… :stuck_out_tongue:

Have you ever sucked on a bleeding cut? Mouth suction creates a few lbs of pressure diff. Just suck several times harder to simulate vacuum.

rule of thumb: 15PSI is the same as putting an object under a lead rod that’s 30" long and one inch across. So, imagine that such a rod is crazy-glued to your skin and is dangling downwards. That’s the 15PSI pressure diff on one square inch. Do the same to the rest of your skin surface. I think your hand would tend to swell up huge, but only until the swelling was halted by the stretched skin.

From all that I’ve read of Cecil and this message board, I’d feel safer sticking my hand out an open window on the space shuttle than, say, clipping my nails with a weed-wacker. Something I saw on the History Channel said that Kittenger’s hand (or the hand of somebody who was doing dangerous experiments on balloons in the upper atmosphere) did indeed become about the size of a baseball glove, but there were no permanent injuries.

From the site provided by ftg, I read this quote:


Who else has?!

If you live at sea level, your blood pressure is approx. resisting 1 atm of air pressure.

Take away the air suddenly + retain the blood pressure = poof.

Meaningless and unwanted contribution:
Aster: greek, star (identical in latin); nautes: greek, sailor. Starsailor!


Do NOT place any portion of your body outside of your craft. While the nature and extent of your injuries may be of debate, the inherant danger of this reckless behaviour is not.

We cannot be responsible for anyone who attempts this at home.

Presuming there is a seal around your arm, you’ll be fine. Vaccuum won’t freeze your hand; actually, it will be quite comfortable. Space is a good insulator. NASA actually experimented with this. After an hour, the guy doing it stopped because he was getting to much blood in his lower arm, but it was fine.

I seem to remember Arthur C Clarke dealing with this in one of his books - I think it was “Earthlight”. He had the crew of a spaceship being rescued via spacewalk though none of them had spacesuits. He stressed the need for keeping the mouth open to avoid explosive decompression, and got the guys to deep breathe on pure oxygen for several minutes befgorehand so their systems were flush with oxygen. He gave them about 5 minutes to cross from one ship to the other.