The SHARP cannon. Hydrogen is compressed . in the tube on top, the gun barrel is on bottom. ... Suppose the barrel of the cannon is a mile long ( @ 1600 meter) and the final velocity v , the one with which the shell emerges, is the escape velocity from the surface of the Earth . ... However, inert payloads (water, food, rocket fuel etc. ) could in principle be sent into space using a huge "super-cannon. ... Next Regular Stop: #31 Far-out Pathways to Space: Nuclear Power . ...