A c/6 spaceship is a spaceship travelling at one sixth of the speed of light. The first such spaceship to be discovered was the dragon, found by Paul Tooke in April 2000. The first diagonally moving example was the seal, found by Nicolay Beluchenko in September 2005. Another orthogonal c/6 spaceship, 274P6H1V0, was found by Paul Tooke in March 2006. For the smallest known c/6 spaceship, see 56P6H1V0.
A Caterloopillar can theoretically be configured to move at c/6, but there are technical difficulties with speeds of the form 4n+2, and as of the end of 2017 this has not been done in practice.