Japetus

Japetus, also known as Kaldor, was the second moon of Saturn. Its geography included at least one vast desert, which held minerals including zelanite, keefan, and lucanol. (PROSE: Legacy)

The most prominent structure on the moon was Kaldor City, one of three original man-made colonies on the moon, populated by humans with sandminer robot servants that tended to their whims and also helped manage the sandminers themselves. The city itself was surrounded by the Outer Zones, which were inhabited by less wealthy members of the society. (AUDIO: Occam's Razor, PROSE: Legacy) The sandminers which collected minerals from the deserts needed to keep moving to avoid sinking into the sand, and windstorms constantly swept over the desert. (TV: The Robots of Death)

By the 29th century, the Founding Families, descendants of the original terraformers, were well established as the governing body of Japetus, in charge of the powerful Kaldor City Corporation. (PROSE: Legacy, AUDIO: Occam's Razor) While the people of Japetus were aware that they were descended from off-world colonists, they purposefully isolated themselves from any contact with other planets for generations, as the Company feared that it might lead to loss of profits. (AUDIO: Occam's Razor).

The Fourth Doctor and Leela visited Kaldor in the 29th century, and became involved in a plot by Taren Capel to make the robots kill all humans. (TV: The Robots of Death)

Years later, however, the people of Kaldor were in contact with other planets and launched spaceships such as The Lorelei. (AUDIO: Robophobia) By the 39th century, minerals were sent to Io for distribution throughout the Galactic Federation. (PROSE: Legacy)

Centuries after the colonisation of Kaldor, an UV-1 robot began to reprogram Super-Vocs to turn them against humans, but this plan was stopped. (COMIC: Crisis on Kaldor)

Behind the scenes

 * In the book Doctor Who: 100 Scariest Monsters, Kaldor is misspelled Caldor.
 * The comic Crisis on Kaldor has the Doctor stating the planet's name to be Kaldor, while the name was previously only thought to be applied to the city.