The Science Behind Building a Space Gun
An anonymous reader writes "Astronomer and gamer Scott Manley (more famous for his Kerbal Space program coverage) has created a fantastic video explaining the science behind building guns that could one day be used to launch payloads into space. It's not as easy as simply making a bigger gun, there's a whole host of unorthodox 'gun' designs which work around the limitations of garden variety propellants."
Everything is expensive. As to what to do with a gun, just launch water into space. It provides fuel, air, food, and of course water.