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 Martians, also known as the Invaders, are the main antagonists from the H.G. Wells 1898 novel The War of the Worlds. Their efforts to exterminate the populace of the Earth and claim the planet for themselves drive the plot and present challenges for the novel's human characters. They are notable for their use of extraterrestrial weaponry far in advance of that of mankind at the time of the invasion.