Blon Slitheen intended to use this to escape early 21st century Cardiff, blowing up Earth and riding away on the subsequent shockwave of energy. After they realised her plan and captured her, the Ninth Doctor and Jack Harkness confiscated it and connected it to augment the recharging of the Doctor's TARDIS. Knowing that anyone who would arrest her would have confiscated the extrapolator, Blon programmed the board to connect the nearest alien power source — in this instance, the TARDIS — to open the Cardiff Space-Time Rift. The strain of pulling the ship apart opened the Heart of the TARDIS and regressed Blon to an egg. The extrapolator remained connected to TARDIS systems. (TV: Boom Town)