Steel Empire is a horizontally scrolling shooter released on the Sega Genesis in 1992. Versions for the Game Boy Advance and Nintendo 3DS were released in 2004 and 2014, respectively. The game is scheduled for release on the Nintendo Switch in 2023.

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.