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Space Calc
Doing the math, so you don't have to.

Ship Decompression


If you get a hole in your spacecraft, the air that's presumably inside it will of-course start rushing out. This calculator will (roughly) calculate how fast this happens, as well as the effect on any free-floating objects.

Note that this calculator assumes that the object remains inside the spacecraft and far away from the hole, and that it is well-approximated by the drag equation.

If the object is closer to the hole, the effects are complicated. Right at the hole, the effect is that the room's cross-sectional area and the hole's cross-sectional area are the same (set them that way below to get an estimate!). Off to the side or farther away, the effect is gentler, eventually converging to the values the calculator returns.

Outside the spacecraft, the equations change dramatically because the air diffuses outward.



Decompressing room's volume: Assume effectively infinite.
Decompressing room's cross-sectional area: (from circle radius or diameter )
Hole's cross-sectional area: (from circle radius or diameter )

Set hole's area the same as room's cross-sectional area

Please note: the hole's cross-sectional area cannot be larger than the room's! If a field seems to be ignoring your input, check that you're not trying to set an invalid value.


With Object
Object mass:
Object cross-sectional area:
Object coefficient of drag:


Derivation and Formulae

Technical Notes

I derived the equations that describe all this and presented my results on Google+, along with a Python script, upon which this calculator was based. The infinite-mass case has subsequently been corrected.

For an overview of real-life incidents and an approximation, see here. If someone can get me a copy of the cited 1953/1954 paper, I'll see if it's better than what I came up with:

Demetriades, S. T. "On the Decompression of a Punctured Pressurized Cabin in Vacuum Flight." Jet Propulsion 24.1 (1954): 35-36.