The last battle of the Third Dalek War was fought on the planet JT227.
History
Spindroids were used to mine the planet as it was radioactive. They guarded it from space in satellites that ringed the world. Humanity's discovery of Promethium 62 meant that the Daleks were at last retreating from human space, as it helped to break Dalek forcefields, forcing the Daleks out of star system after system. However, the Daleks found the source of the element: JT227. They arrived and appeared from hyperspace in the parts of every one of the two hundred satellites orbiting JT227.
The Spindroids went on full alert and fought the Daleks faster and harder than humans ever could. The Daleks breached only a few of the satellites. Although their Promethium-hardened casings couldn't withstand Dalek firepower well, the Spindroids destroyed the Daleks, armed with their own blasters and deadly blades. After the disastrous defeat, the Daleks vanished from the human front. (PROSE: The Match of the Daleks [+]Loading...["The Match of the Daleks (short story)"])