GodEngine
The GodEngine was a super-weapon created by the Native Martians (Ice Warriors) from remnants of Osirian technology left on Mars long ago. This device was capable of destroying a star by making it go supernova.
The weapon required a planetary mass to tether it against the subspace fields it generated but it was only operational in the absence of a bipolar magnetic field. One Ice Warrior group offered the Daleks the use of the GodEngine in return for the conquest of Mars for themselves which was why the Daleks were intending to remove the Earth's magnetic core.
To activate the weapon, a key was required which was actually shaped into the Sword of Tuburr. It was noted by the Doctor that the destruction of the GodEngine would fill subspace with exotic particles that would ruin the Icaron generator. (NA: GodEngine).
