Vacuum exposure

Vacuum

An anatomy of death in low pressure

An unprotected body in hard vacuum does not explode and does not freeze solid. It boils, briefly, at the temperature it already is. What follows takes about a minute, and then a very long time.

Depicts the death of a human being. The images are speculative reconstructions; the physiology is not.

Scroll to begin descent

PartI

Ebullism

T + 00:00 → 00:10

The water in his blood remembers it was always a gas.

Below roughly 6.3 kilopascals — the Armstrong limit — water boils at body temperature. Pressure does not need to reach zero for this; it only needs to fall far enough, and it falls in under a second. Vapour leaves first from wherever the body is wettest and least enclosed: the mouth, the sinuses, the surface of the eyes.

An astronaut spins in the mouth of an airlock, backlit by hard white light, a turbulent cloud of vapour bursting from his mouth and nose. His face is lost in the glare.

The same face, closer: the eyes reddened and glazed, ice gathering along the lashes, vapour streaming from the nose and mouth across the frame.

PartII

Anoxia

T + 00:10 → 00:15

The thrashing stops before the falling does.

Lungs are no use now; at this pressure they empty rather than fill, and holding a breath only ruptures them. What is left is the oxygen already dissolved in the blood between the lungs and the brain — nine seconds of it, perhaps fifteen. It runs out mid-motion. The body does not slow down. It simply stops being driven.

The same astronaut, limp and drifting in a bright white corridor. The vapour has gone. Nothing about his posture is intentional any more.

PartIII

Edema and Frost

T + 00:15 → 01:00

He is not freezing. He is evaporating, and the leaving takes the heat with it.

Vacuum is an excellent insulator — there is nothing to conduct heat into. So the body cools the only way left to it, by boiling its own moisture away, and the surface frosts while the tissue underneath continues to swell. Roughly twice its volume, held in by the suit. The cold is a symptom of the drying, not the cause of the death.

A tight view of the suit's collar ring and shoulder, every surface furred with fine white frost. The face above is a shape in deep shadow.

PartIV

And Beyond the Infinite

T + YEARS

Nothing out here is coming to take him apart.

Decomposition is something living things do to a body, and there are none. No microbes, no oxygen, no weather, no water. The desiccation finishes itself and then stops, because there is nothing left to remove and no process to remove it. What remains keeps its shape, keeps its heading, and keeps them both for longer than the word 'years' is useful for.

Years later, in deep space lit only by cold blue starlight: the suit is cracked and faded, drawn tight over a shrunken body. Where the face was there is a dark hollow inside the neck ring.

1 : 4 : 9

He will arrive somewhere, eventually, entirely unchanged.

Nothing out here is dense enough to erode him, warm enough to thaw him, or alive enough to consume him. Preservation is not something being done to the body; it is simply what happens when every process that would undo it is absent. The suit will outlast the mission, the agency that launched it, and most likely the language its checklists were written in.