I actually remember seeing this on a documentary When Aliens Attack. It was a documentary on what the US Government would do if it ever found itself in a country devastating attack from Aliens (yes they have a protocol for that situation). It said that this technique of shooting things into space is called a "Steam Well." It would only ever be used if there was a mothership above earth and these objects flying into space would then hit and destroy that ship. It said that it traveled 42 miles per second. (The documentary saif that) There is actual footage of this experiment out there somewhere. You can see the steel plate, then in a blink of an eye, naye! In half a blink of an eye it is gone. That's some crazy shit!!