Sontaran scout ship
Sontaran Scout ships were large, spherical vehicles created by the Sontarans to scout ahead before a fleet to investigate or infiltrate the enemy.
Jingo Linx was forced to deploy his scout ship but it was damaged and he had to land on earth where he and it were destroyed. (DW: The Time Warrior)
Styre used his scout ship as a base on earth in the future while he experimented on humanity (DW: The Sontaran Experiment)
Three scout ships attacked the Space Station Chimera, after which one- piloted by Stike- landed near Seville. After this it was placed in clear and then destroyed when it was set to self destruct. (DW: The Two Doctors) In this story the scout ships are named as Sontaran Battle Cruisers not scout ships by the computer on the space station Chimera.
Several scout ships orbited the main Sontaran flagship during the Sontaran invasion of Earth. (DW: The Sontaran Stratagem / The Poison Sky)
Kaagh was in a scout ship as he crashed to earth. with his arm strap he was able to move the ship to hidden location and even make it invisable, he also had chemicals in his ship. (SJA: The Last Sontaran)