HERE IS A MODEL of the NAZI SILBERVOGEL Space Plane. It is unclear if they actually built it. Drawings captured after the war, show they were planning to do so. It had a Gravity Neutralization component in it. The purpose of it were to take bombs in to space, and fly it directly over the target and drop it out of space directly on to the target, and no one would know where it came from. Hmmmmmm - - nothing has changed. That is what the USA and Russia has developed now.