In movies/cartoons you see astronauts and people in spaceships opening doors and closing them again with no suits on. Is it possible in "real life" or would you die immediately? Because consider this:

  1. If we built some giant space colony/living facility (like in Star Trek), isn't there always the danger of someone opening a way outside from which you could die instantly if no one is in a spacesuit (if true?)?

  2. What about the fear of being in closed, confined spaces too long? Some people may panic and even kill themselves/others or become destructive in chaos from being trapped in an enclosed space colony.

Obviously an alternative to the long-winded process of terraforming other planets is to create safe ships to fly around in and live in. And future technology could prove this to be better than terraforming since a spaceship is magnitudes more versatile and easier to self-sustain and maintain than a gigantic planet.

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    $\begingroup$ I think the question can be improved if the last two paragraphs are removed completely; not really physics related. And even then, I would be surprised if this weren't a duplicate. $\endgroup$
    – BMS
    Commented Mar 23, 2015 at 5:15
  • $\begingroup$ Possible duplicates: physics.stackexchange.com/q/122993/2451 , physics.stackexchange.com/q/3076/2451 and links therein. $\endgroup$
    – Qmechanic
    Commented Mar 23, 2015 at 7:33
  • $\begingroup$ Don't think you would die immediately but you probably wish you could, as the exposure to vacuum sounds horrendous. en.m.wikipedia.org/wiki/Space_exposure $\endgroup$
    – user74893
    Commented Mar 23, 2015 at 11:49
  • $\begingroup$ There was a scene in 2001: A Space Odyssey where this was portrayed after a fashion. Analysis at the time, presumably some of it expert, suggested that the scenario was reasonably accurate and the astronaut involved had a reasonable chance of survival. $\endgroup$
    – Hot Licks
    Commented Mar 23, 2015 at 15:57
  • $\begingroup$ The Columbia astronauts were unconscious after 15 seconds of vacuum. Once I talked with a professional pilot, he said they were trained for, how decompression feels. There is no feel of asphyxia (it has a different biological reason), rather they feel their body very weighty. And unconsciousness comes very fast and unavoidable. $\endgroup$
    – peterh
    Commented Apr 20, 2017 at 20:59

3 Answers 3


The biggest, immediate problem with "openning the door" of a spacecraft is not that you would die immediately from exposure to the vacuum of space: you don't - you have of the order of minutes to do something about it.

The problem is the violent outrush of air. User rob offers this answer to the Physics SE question Do airlocks in space decompress violently as they do in movies?. With its containing vessel suddenly open, air, from its thermal motion, suddenly becomes a rush outwards that's really going to whack you big time: rob does a calculation that shows that being shoved by this outrush is to suffer the same order of impulse as you would being hit by a car.

If you are uninjured by the blow, once in space you could be quite OK if someone could get you a lifeline in a few minutes. Given the size of the blow above, it's likely going to need to be a long lifeline, but, as explained by Phonon's answer to the physics SE question What exactly happens to an exposed human body in space? if you get back inside in a minute or two, you'll likely be OK. You may need some hyperbaric oxygen treatment to lower any risk of "The Bends" - although your blood wouldn't boil violently, your blood may have micro-clots that divers for example have after an emergency free ascent in it. You may be also be really unlucky and be pierced to death by a micrometeorite, but this is not likely.

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    $\begingroup$ Although you could probably survive for a couple of minutes in vacuum, you would lose consciousness extremely rapidly (in a matter of seconds). So hopefully your survival plan doesn't require you to take any action to rescue yourself. $\endgroup$
    – David
    Commented Mar 23, 2015 at 10:08
  • $\begingroup$ Tangential (a story by Arthur C Clarke) story: Take a Deep Breath. It doesn't go too far into the hard science, but also makes mention of another possible problem... the unfiltered Sun sunburn. $\endgroup$
    – user20936
    Commented Mar 23, 2015 at 13:26
  • $\begingroup$ It's worth noting that the calculation in that answer for the force of outrushing air used a 20m^3 volume. That's much larger than a plausible personnel airlock would be. $\endgroup$ Commented Mar 23, 2015 at 14:26
  • $\begingroup$ It's also worth noting that taking a deep breath and holding it is about the worst possible thing you could do before opening the door - your lungs will rupture, and probably your chest cavity too. It's known among divers as "pulmonary barotrauma". $\endgroup$
    – Fax
    Commented Mar 6, 2020 at 19:33

people in spaceships opening doors and closing them again with no suits on. Is it possible in "real life"

No, it is not.

Any sane engineer will build doors that open inward, or have latches that over-center when closed so it is simply impossible to open an airlock in a pressurized vessel. An aircraft, for example, has about 6-8 tons of pressure holding the door against the frame. Superman himself won't open the door against that much force, simply because the handle will break off.

In sci-fi shirtsleeve airlocks the air is held in by a forcefield, the door can then be opened and closed with impunity.

If you really want to know what happens to humans in explosive decompression situations (it's not pretty) search for the Byford Dolphin decompression accident.

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    $\begingroup$ "6-8 tons of pressures..." Tons is not a unit of pressure $\endgroup$
    – Sean
    Commented Mar 23, 2015 at 11:20
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    $\begingroup$ @Sean pounds per square inch is a unit of pressure, aircraft doors are a well-known size, solve for force / door and reduce to largest convenient unit. $\endgroup$
    – paul
    Commented Mar 23, 2015 at 12:25
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    $\begingroup$ Superman could definitely open a door held shut but such a small amount of pressure. He has enough strength to bench-press the weight of the Earth easily for five straight days in the New 52. Please read up on your comic book superheroes before using them in Physics answers :-) $\endgroup$
    – TylerH
    Commented Mar 23, 2015 at 16:36
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    $\begingroup$ In the Byford Dolphin incident, the initial pressure was 9 atmospheres, which explosively decompressed down to (I assume) 1 atm, for a differential of 8 atm. Suddenly decompressing from 1 atm to hard vacuum is 1/8 the differential, which means much less chance for things to explode messily. $\endgroup$ Commented Mar 23, 2015 at 18:43
  • $\begingroup$ @TylerH if you read a few more words of that sentence you will see I am not questioning the Man of Steel's strength, I am doubting the strength of the handle he pulls on. If he grabs the door elsewhere it will damage the door which will prevent the "closing it again" part. $\endgroup$
    – paul
    Commented Apr 3, 2015 at 14:40

Bad Things Happen

The air, as it has no pressure or enough gravity to keep it in the ship, will attempt to expand. Air, in fact, attempts to expand to fill the container it is placed in. If there is no walls to the container, like on a planet, it will only be stopped by gravity.

When the airlock is unsafely open or a hole is made in a spaceship, the air inside attempts to fill the void of space. Space is really big, as truly pointed out in many scifi movies, despite their other many other false claims about it. This means the the air pressure practically drops to zero, as practically all the air moves out of the spaceship in a terribly feeble attempt to fill the void.

Depending on how quickly the air moves out, and how large the hole is, you may have a few seconds or less to realize your fate. Scishow does an accurate and entertaining video on being exposed to the vacuum of space. You actually go unconscious really quickly, as your bodily fluids boil off your exposed surfaces (including your lungs). The oxygen pressure in your blood drops, and you black out. After that, you do an interesting freeze/burn combo as the sun cooks you on one side and you freeze on the other. It does not sound pretty.

Fighting Claustrophobia

Windows. This may be the number one reason to have windows on your ship. Being able to see out, a feeling of a very open space, will help those with claustrophobia fight their fears, or at least give them refuge from them.

If you're the type of sci-fi reader who believes in holodecks or other VR, they can help with that, too. Ultimately, this isn't a physics question, but a better one for the cognitive sciences stack exchange.

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    $\begingroup$ Space is so big indeed, that the simple Avogadro explanation about air filling the void is no longer fully accurate - in fact once outside the airlock, your air molecules won't ever meet again so that usual laws of gases don't apply. The molecules just start (and keep) moving straight away at their thermal velocity of some hundred meters per second. $\endgroup$ Commented Mar 23, 2015 at 7:09

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