Scout ship

From Tardis Wiki, the free Doctor Who reference

Scout ships were reconnaissance craft that could be detached from a mothership. Human spacecraft such as the Hydrax had three scout ships fronted with bolts of steel. One of these was used by the Fourth Doctor as a gigantic "stake" to kill the King Vampire. (TV: State of Decay)

The Sontarans had spherical scout ships that each contained a single Sontaran. (TV: The Time Warrior)