How long could you survive in the vacuum of space?

As the school year comes to an end for seniors, I traditionally show the film 2001: A Space Odyssey. In the film, astronaut Dave Bowman finds himself stuck in a small space pod, locked out of the main spacecraft, without the helmet to his spacesuit. Forced to enter through the emergency air lock, Dave is briefly subjected to the vacuum of space. Is it possible for him to survive? The answer, according to science fiction writer Geoffrey Landis, is YES. Landis, who referenced several sources, explains that a human can remain mentally conscious in the vacuum of space for about 10 seconds, and survive that environment for about 90 seconds. As soon as the astronaut hits the vacuum, air will be knocked out of the lungs through the nose and mouth. Space is a very cold and very hot place; without an atmosphere to even things out, the difference between sunlight and shade is 400 degrees F. The mouth and tongue may freeze, it will only take a short time for skin not exposed to the sun to get lightly frostbitten, and skin exposed to the sun will be badly sunburned. But that's about the worst of it inside of 90 seconds of exposure. Unless the astronaut tries to hold their breath...this will cause the lungs to rupture. So, as a safety tip, if you’re going for a space walk without a helmet, keep your mouth open. Eventually, like deep-sea divers coming up to the surface too quickly, gas bubbles will form in the astronaut's blood and soft tissues -- a condition called "the bends". Hypothermia, or a harmful drop in core body temperature, will set in, but is not a short-term concern. Link.