Sontaran scout ship

Sontaran scout ships, also called battlecruisers (TV: The Two Doctors) or battlespheres, (AUDIO: Starlight Robbery) were large, spherical spacecraft used by the Sontarans to scout in advance of a fleet to investigate or infiltrate the enemy.

Usage
When the Sontarans joined the Alliance, formed to imprison the Eleventh Doctor in the Pandorica and save the Universe, several Sontaran scout ships were part of the Alliance fleet which arrived at Stonehenge in 102 A.D. (TV: The Pandorica Opens)

In the 13th century, Jingo Linx was forced to deploy his scout ship, but it was damaged. He had to land on Earth where he and it were destroyed. (TV: The Time Warrior)

In 1522, a Sontaran scout ship crashed in China. (COMIC: Dragon's Claw)

UNIT believed that a Sontaran scout ship crashed in Tunguska in the early 20th century, though they weren't entirely sure. They kept some of this wreckage in the Vault. (AUDIO: Tales from the Vault)

Several scout ships orbited the main Sontaran flagship during the Sontaran invasion of Earth in 2009. (TV: The Sontaran Stratagem / The Poison Sky) Kaagh was in one of these scout ship when it crashed to Earth. With his arm strap he moved the ship to a hidden location and even made it invisible. (TV: The Last Sontaran)

In 2010, UNIT Underbase contained a Sontaran scout ship. (COMIC: The Age of Ice)

In the early 21st century, UNIT's Vault contained a fragment of a Sontaran scout ship. (AUDIO: Tales from the Vault, The Screaming Skull)