Gerald Vincent Bull was a Canadian engineer who developed long-range artillery. He moved from project to project in his quest to economically launch a satellite using a huge artillery piece, to which end he designed the Project Babylon "supergun" for Saddam Hussein's government in Iraq.
Bull at the Space Research Institute of McGill University in 1964
The remains of the abandoned Gun from Project HARP in Barbados.
The GC-45 howitzer as designed and manufactured by Space Research Corporation
A section of the Iraqi supergun Big Babylon
A space gun, sometimes called a Verne gun because of its appearance in From the Earth to the Moon by Jules Verne, is a method of launching an object into space using a large gun- or cannon-like structure. Space guns could thus potentially provide a method of non-rocket spacelaunch. It has been conjectured that space guns could place satellites into Earth's orbit, and could also launch spacecraft beyond Earth's gravitational pull and into other parts of the Solar System by exceeding Earth's escape velocity of about 11.20 km/s. However, these speeds are too far into the hypersonic range for most practical propulsion systems and also would cause most objects to burn up due to aerodynamic heating or be torn apart by aerodynamic drag.
Therefore, a more likely future use of space guns would be to launch objects into Low Earth orbit, at which point attached rockets could be fired or the objects could be "collected" by maneuverable orbiting satellites.
The Quicklauncher spacegun
Two sections of the Project Babylon gun
Project HARP, a prototype of a space gun.
The firing of a space gun in Jules Verne's From the Earth to the Moon