Relative Dimensional Stabiliser The Relative Dimensional Stabiliser ( simply called RDS or , more often , dimensional stabiliser ) was a component of a TARDIS control system , which allowed to cross the dimensional barrier ( TV : " The Invisible Enemy " ) or , in other words , which regulated the outer plasmic shell of the ship in relation to its exterior . Some of its functions and / or components include a chronostat and " synaptic adesion " . ( TV : " The Armageddon Factor " ) TARDIS . The relative dimensional stabiliser field prevented Andred from firing his staser in the Doctor ' s TARDIS . ( TV : " The Invasion of Time " ) The Fifth Doctor asked if there was a problem with the dimensional stabiliser , causing turbulence . ( TV : " Time - Flight " ) On one occasion , space pressure reduced both the interior and the exterior of the Doctor ' s TARDIS to minute size without affecting the passengers adversely . ( TV : " Planet of Giants " ) On Moldox , the War Doctor and Cinder jumped into his crashed TARDIS , laying on its side , and found themselves the right way up . He explained to her that the relative dimensional stabilisers prevented them to " fall " , since the inside could be orientated differently to the outside . ( PROSE : " Engines of War " ) Other uses . The item could be used to change the dimensions of living beings or other external targets . In 5000 , Professor Marius used the relative dimensional stabiliser of the Doctor ' s TARDIS to shrink down clones of the Fourth Doctor , Leela and Lowe , and enlarge the Nucleus of the Swarm , bringing it into the macrocosm world . ( TV : " The Invisible Enemy " ) By using the dimensional stabiliser of the Drax ' s TARDIS , the Fourth Doctor and his fellow Time Lord reduced their own size in order to catch the Shadow . ( TV : " The Armageddon Factor " ) The Sixth Doctor expanded the dimensional stabilisation field of Straxus ' TARDIS to an entire pocket dimension he was trapped in by a machination of the Master ; this let four other incarnations of the Doctor ( the Fourth , the Fifth , the Seventh and the Eighth ) to fully materialise with their own TARDISes in the dimension itself . This use of the RDS implied the destruction of the Straxus ' TARDIS . ( AUDIO : " The Light at the End " ) Behind the scenes . The video game " Attack of the Graske " referred to the dimensional stabliser in a gameplay mechanic as a yellow lever that helped the player at home fly the TARDIS to 19th century Earth . This same lever was operated by Sarah Jane Smith in " Journey ' s End " to assist in returning the Earth from the Medusa Cascade . As " Attack of the Graske " involves multiple choices of endings , this wiki does not consider it a . In Russell T Davies ' book " The Writer ' s Tale " , the full original draft of " Journey ' s End " has the Tenth Doctor stating that it takes " thousands of years " to grow a TARDIS . However , Donna uses her newfound Time Lord knowledge enhanced by human intuition to overcome this problem by suggesting : " . . . if you shatterfry the plasmic shell and modify the dimensional stabiliser to a foldback harmonic of 36 . 3 , you accelerate growth by the power of 59 ! " , which would presumably enable a TARDIS to grow within a human lifetime . The scene is included as a bonus feature with the series 4 DVD box set released in November 2008 .