Interstellar travel
From Tardis Wiki, the free Doctor Who reference
As observed by the Third Doctor, human interstellar travel within the Milky Way galaxy was "pretty routine" by the 26th century. (TV: Frontier in Space)
The Fifth Doctor noted that the rocket pads of a spacecraft were too small for interstellar travel, reasoning that it came from Androzani Minor. (TV: The Caves of Androzani)
The Twelfth Doctor found that a sea creature produced fuel suitable for interstellar travel. (TV: Thin Ice)
