Frontios

Frontios is a planet that the the Doctor visited during the course of his adventures.

Location
Frontios is located in the Veruna system.

Further Information
Frontios' atmosphere is close to that of Earth - Humans, Trions and Time Lords are able to breathe without requiring special apparatus. The soil composition appears to be mostly low-level scree and porous rocks. Beneath ground level, there is a vast network of tunnels mined by the Tractators in an attempt to turn the planet into a gravitic motor. Stone suitable for quarrying and building material is also available.

Human Colonisation
At the very periphery of the Time Lords sphere of knowledge, Frontios became home to a fledgling colony of human refugees who were one of the last Humans to leave the Earth in a ship captained by Captain Revere.

Frontios was not the original destination of the colony ship, but it was pulled off-course by the Tractators (led by the Gravis) and crashed into the planet, where the surviving crew and colonists were bombarded with meteors, and randomly selected for enslavement in the Tractators' mining machines.

After the removal of the Gravis, the Tractators became harmless, earth-burrowing creatures. No mention has been made of their removal from the planet, so most likely they co-habit the planet with the human colonists. (DW: Frontios)