Vacuum

A vacuum was an area that was virtually empty of matter. The most commonly known was that of space. Most life forms could not survive in a vacuum for very long.

There were, however, those who were able to survive in the vacuum of space indefinitely or for extended periods of time. These included:
 * Time Lords, for limited periods. (DW: Four to Doomsday, TARDIS)
 * Daleks. (DW: The Parting of the Ways)
 * Cybermen. (DW: The Moonbase)
 * Toby Zed, while possessed by the Beast. (DW: The Impossible Planet)
 * Star Whale. (DW: The Beast Below)
 * Ahab. (K9TV: The Bounty Hunter)

Individuals killed by exposure to vacuum

 * Katarina. (DW: The Daleks' Master Plan)
 * Kirksen. (DW: The Daleks' Master Plan)
 * Varan. (DW: The Mutants)
 * Lynda Moss. (DW: The Parting of the Ways)
 * Scooti Manista. (DW: The Impossible Planet)
 * Chief Steward. (DW: Voyage of the Damned)