How long can a human in outer space last without a spacesuit before exploding?

Category: Space
Published: December 17, 2012

By: Christopher S. Baird, author of The Top 50 Science Questions with Surprising Answers and physics professor at West Texas A&M University

Humans don't explode in space. Even though outer space represents a lack of air pressure, which usually counters the internal pressure in our bodies, our tissue is strong enough to handle the imbalance. According to Richard Harding's book "Survival in Space," the blood vessels can withstand the internal pressure without exploding. Humans do die if left in outer space without a space suit. But they die for the same reason as people who are left too long underwater: lack of oxygen. The Federal Aviation Administration reports in advisory circular 61-107 that humans remain fully conscious and useful for 9-12 seconds after being exposed to a vacuum. There are other dangerous effects that the spacesuits protect against, such as cold and radiation, but these do not cause immediate death, and they definitely don't cause explosion.

Humans exposed to the vacuum of space don't explode. In fact, if this astronaut's helmet popped off, he would be alert and conscience for several seconds. Public Domain Image, source: NASA.

Topics: explosive decompression, spacesuit, vacuum, vacuum exposure