(Image credit: Getty Images/SCIEPRO/SCIENCE PHOTO LIBRARY) You've seen it in a thousand sci-fi movies : an astronaut is ejected into space and freezes instantly, then shatters like an ice cube. A hairline crack appears in a helmet, and a character asphyxiates in seconds, desperately pawing at their spacesuit as they sink to their knees, and their skin turns blue. Maybe a sleek ship is being chased by enemy fighters through a dense asteroid field, and one of them smashes into a massive space rock and is explosively atomized. Explosive vacuum exposure — the most misunderstood killer Douglas Quaid (Arnold Schwarzenegger) suffers the effects of the Martian atmosphere in the sci-fi movie "Total Recall" (Image credit: Tri-Star Pictures) The movie myth perpetuated by classics like "Total Recall" (1990) and "Mission To Mars" (2000) is that exposure to the vacuum of space would cause your body to immediately atomize and explode or, alternately, flash freeze to a solid block of ice the moment you leave a space with…