The X-L (short for "Extra-Large") series is a series of American-made space rockets automatically piloted by "see-through" robots. As a tradition, each vessel is traditionally named after the manner of its predecessor's destruction.
- Mushroom Cloud X-L 2
- Shrapnel X-L 3
- Pancake X-L 4
The X-L series are based on the 1962 science fiction-themed children's television show Fireball XL5, which was produced by Gerry and Sylvia Anderson. In The League of Extraordinary Gentlemen: Black Dossier, Mina Murray and Allan Quatermain stole Pancake X-L 4 which is destroyed by a collision with a mountain, exploding in a huge fireball and implicitly earning X-L 5 its name.
The robot pilots made of "perspex" and which are named "Ronald or Roderick" is a reference to Robby the Robot from the 1956 movie Forbidden Planet.