Space movies regularly dispatch characters through an explosively decompressed airlock. But how likely is such a rapid ejection, taking into account the victim’s location in the airlock and its volume? Assuming they are wearing a spacesuit, what is the best way to avoid expulsion, apart from grabbing something solid?
• By a sad coincidence, at about the time this question was published (21 April), an aircraft passenger was killed in a similar way. An engine explosion blew a piece of metal through a window and the air escaping from the plane blew (not sucked as the media put it) a passenger partially out of the window.
In practice, everything depends on the geometry. In a passenger plane, the volume of air inside is usually quite large compared with the size of the opening, so the air will be blowing out for some time until the pressure is equalised.
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In a spacecraft airlock, the door is likely to be larger than a plane window, and the volume of the airlock smaller, but the outside pressure will be zero. The pressure inside can’t be too low otherwise the spacecraft passengers will suffer from anoxia when not wearing spacesuits. So the pressure difference is greater and the initial blast will be stronger, but the lower volume means it will not last as long as on an aircraft. If you are near the airlock door, you could very possibly be blown out, particularly if you are standing by it since your effective cross-sectional area will be larger. If the door only opens partially, you are actually more likely to be blown out because the opening is smaller and the blast will last longer until the air in the airlock is exhausted.
Holding on to something to avoid being blown out will not help much: your grip is unlikely to be strong enough, and even if it is, your arm may be wrenched off. The best way to avoid such an accident is to enter only small airlocks with large doors, and stay near the wall opposite the door until the airlock is depressurised. Unfortunately, real airlocks tend to have small doors because large doors have to be stronger and are harder to seal.
The first fictional account of someone being dispatched in this way may be the defenestration of Oddjob from a plane by James Bond in Goldfinger, Ian Fleming’s 1959 novel.
Richard Parkins, Cambridge, UK
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