A Mass Driver is a large Railgun that fires large multi-ton blocks of metal or rock at a very high velocity, used to bombard planetary surfaces from orbit. When such massive objects impact a surface at a significant fraction of the speed of light, kinetic energy is converted to thermal energy, resulting in an explosion as powerful as a small nuclear bomb, but without the radioactive fallout and other secondary radiation effects. Mass Drivers are now carried moslty in external turrets on larger warships and many transports.
Behind the Scenes[]
Mass Drivers show up frequently in science fiction, and are one of the more scarily realistic technologies in the genre, but those in TI are more specifically inspired by those from Babylon 5 and The Moon is a Harsh Mistress.