Fourth Sector

From Tardis Wiki, the free Doctor Who reference

The Fourth Sector was the fourth sector of the Mutter's Spiral, fifty days and many billions of miles out from Earth. Planets in the sector included New Sarum, Ta in the Pliny system, Lobos, (TV: The Space Pirates) and the human colony world New Houston. (AUDIO: The Yes Men)

Argonite, the most valuable mineral known to humans, was only found on the planets of the Fourth Sector. Eighteen Earth Government space navigation beacons were scattered across the sector, millions of miles apart. Maurice Caven's space pirates targeted the beacons and cargo ships in the sector for their argonite. (TV: The Space Pirates)