Solar wind
From Tardis Wiki, the free Doctor Who reference
Solar wind was charged particles emitted by stars. They could be used to travel through space, pushing an object along like a sailboat.
The ships in the race for Enlightenment travelled by solar winds. The Buccaneer was designed to be able to move in the slightest breeze of solar wind. (TV: Enlightenment) The Veltrochni Dragon cruisers also travelled by harnessing solar winds. (PROSE: The Dark Path)
The Isolus naturally travelled through space via solar winds. (TV: Fear Her)
Kastria was protected from solar winds by a barrier set up by Eldrad. After he shut it down, the planet was ravaged, leaving it barren and lifeless. (TV: The Hand of Fear)
