TARDIS


 * This is a general article on a type of vessel. For discussion of the vehicle used by the Doctor, see The Doctor's TARDIS and TARDIS (disambiguation). 

A TARDIS or TT Capsule was the main kind of space-time vehicle used by the Time Lords.

Name
"TARDIS" was an acronym. Susan explained to Ian Chesterton and Barbara Wright that she had "made up the name 'TARDIS' from the initials" of the full name, "Time And Relative Dimension In Space". (DW: An Unearthly Child) Although some Time Lords, like Castellan Spandrell and Romana, utilized the more generic name "TT capsule" (DW: The Deadly Assassin, The Pirate Planet), others were perfectly familiar with Susan's acronym. (DW: The Three Doctors, NA: Lungbarrow, BBCR/BFA: Human Resources) Some beings on the fringes of Time Lord society, like the Sisterhood of Karn, also knew the acronym without being prompted by the Doctor or his companions. (DW: The Brain of Morbius)

There was a slight discrepancy as to the precise meaning of the acronym, however. Vicki pluralized the fourth word when she explained the term to Steven, making it stand for "Dimensions". (DW: The Time Meddler) This interpretation seemed to hold for a time, being used by several subsequent companions and Doctors. (DW: The Wheel in Space)

Nevertheless, the singular Dimension, may have been "more correct", as the Doctor's fifth, eighth, ninth and tenth incarnations — as well as their respective companions — consistently preferred the original, singular form. (DW: Frontios, Doctor Who (1996), Rose, Smith and Jones, Turn Left)

Types
TARDISes were of two broad categories — exploratory and military. Of the two, TARDISes without armaments were apparently more common.

Exploratory
Most TARDISes were used merely for the observation of various places and times. This kind of TARDIS underwent much modification over the years. Each new model received a distinct number to differentiate it from other models. The numerical scheme was seemingly simple; the higher the number, the later the design had been produced. However, two types of numbering schemes may have been employed. The Monk called his version a "Mark 4", and the First Doctor's reaction seemed to suggest that he had a lower-numbered model. (DW: The Time Meddler) Subsequent incarnations and other Time Lords called the Doctor's TARDIS a "Type 40". (DW: The Ribos Operation) It is additionally possible that each type had several marks. Thus, both the Monk and the Doctor might have had "Type 40s", with the Monk's being a later version of a Type 40.

Whatever the case, TARDISes were generally referred to using the nomenclature Type X. For instance, the Second Doctor, while working for the Celestial Intervention Agency, was briefly assigned a Type 97 TARDIS. (PDA: World Game) The Fifth Doctor once remarked that he should have upgraded to a Type 57 TARDIS. (DW: Warriors of the Deep) In his eighth incarnation, he encountered the Type 102, which appeared to be a near-Human. (EDA: Alien Bodies)

Older models of TARDIS were forcibly withdrawn from service by the government of Gallifrey. By at least the time of the Doctor's fourth life, the entire Type 40 line had been retired from use. (DW: The Deadly Assassin) This policy ostensibly helped the Time Lords police the use of time travel by reducing the total number of TT capsules possibly in use at a given moment in time. Policing was further assisted by ensuring that individual units of the same model had the same key. Thus the Castellan's guards were able to easily effect entry into the Doctor's TARDIS. (DW: The Invasion of Time)

Military
On more than one occasion, the Doctor encountered heavily armed battle TARDISes armed with time torpedoes, first developed during his fifth incarnation or earlier. (DWM: The Stockbridge Horror, BFA: Neverland)

Features and functions

 * For basic information on TARDISes similar to the Doctor's, see Type 40.

Dimensionally transcendental
The signature feature of a TARDIS was that the interior exists in an different dimension than the exterior. The main application of this concept was that it was a different size on the inside than the out. With the exception of Iris Wildthyme and Professor Chronotis' TARDISes, this meant that they were bigger on the inside than the outside. (DW: The Robots of Death) The secondary, but arguably more important, implication was that they could travel by means of "disappearing here and reappearing there." (DW: Rose)

Chameleon circuit

 * See main article.

An obvious feature of all TARDISes was their ability to blend into their surroundings once they landed. If working properly, a chameleon circuit would assess the surroundings just before arrival and change the exterior to resemble a thing common to that landscape. (DW: An Unearthly Child, Rose, Boom Town) On the one occasion he got it working, the Doctor's chameleon circuit appeared to give him no control over the change, as it was an automatic circuit. (DW: Attack of the Cybermen) Later models may have allowed greater flexibility. The Master's ability to produce an ionic column in incongruous environments (DW: Logopolis, Castrovalva, Time-Flight), as well as the Monk's statement that he chose to make his TARDIS look like a sarcophagus (DW: The Time Meddler), perhaps indicated that the circuits of later models could indeed be manually operated. ''In Logopolis, it is implied that the Doctor could select what the TARDIS would look like. He even demonstrates to Adric how he would change the TARDIS into a pyramid, if the chameleon circuit were functioning properly.''

Organic machines?
TARDISes were incredibly complex machines, the nature of their construction was such that they were said to be grown rather than constructed (DW: The Impossible Planet), thus simulating a biological process though it is not clear whether this is indicative of the machine being biological in nature or simply so intricate and complex as to appear to mimic the processes of a biological entity. Due to the level of complexity in their construction, TARDISes had a certain degree of sentience, and could take independent action, such as when the Doctor's TARDIS resurrected Grace and Chang Lee (DW: Doctor Who (1996)), or non-Time Lords looking into the heart of the TARDIS had varying results. (DW: Boom Town, The Parting of the Ways) Due to conflicting evidence from various sources, such as other Time Lords and the Doctor himself it is unclear to what extent a TARDIS is alive, and whether that life extends beyond artificial sentience and into a biological existence.

TARDISes often "mourned" the death of their Time Lord pilots, even going so far as to commit suicide by flying into a sun or simply hurling themselves into the Time Vortex. The Fifth Doctor claimed there was "an elephants' graveyard" of TARDISes somewhere at the end of time. (BFA: Omega, The Axis of Insanity)

Because the TARDIS displayed these organic traits, the Doctor considered his TARDIS to be alive. He talked to and stroked parts of the TARDIS when he operated it. (DW: School Reunion) He diagnosed mechanical difficulties as medical conditions like "indigestion." (DW: The Runaway Bride) He once commented that a TARDIS was "more like a person." (DW: The Five Doctors) Even the Supreme Dalek invited the Doctor to "feel it die", when he believed he had successfully destroyed the TARDIS. (DW: Journey's End) In at least some situations, Time Lords could give up some of their life essence to power up a TARDIS. (DW: Rise of the Cybermen)

Rassilon Imprimatur
Before a TARDIS was fully functional, it needed to be primed with the biological imprint from the symbiotic nuclei of a Time Lord's cells. Known as the Rassilon Imprimatur, this gave them a symbiotic link to their TARDISes and allowed them to survive the physical stresses of time travel. Without the Imprimatur, molecular disintegration would result — a safeguard against misuse of time travel — even if the TARDIS technology were copied. Once a time machine was properly primed, however, and the imprint stored on a component (a briode nebuliser), it could be used safely by any species. (DW: The Two Doctors)

Other

 * See List of TARDIS components

The Doctor's TARDIS

 * See main article.

The Doctor stole his TARDIS. (DW: The War Games, Planet of the Dead) By the time of his fourth incarnation, all other Type 40s had been de-commisioned, save his and that owned by the Master. (DW: The Deadly Assassin) Following the events of the Last Great Time War, the Doctor believed that his was the last TARDIS in existence. (DW: Rise of the Cybermen)

Possessed by other renegades
The Master possessed at least two TARDISes. According to the Doctor, the Master's had a Mark II dematerialisation circuit. (DW: Terror of the Autons) The Rani, the Monk and Iris Wildthyme also had TARDISes, with the latter's possibly even older than the Doctor's.
 * See The Master's TARDIS, the Monk's TARDIS and Iris Wildthyme's TARDIS for more information.



Unique TARDISes
Compassion (a former member of the Remote) evolved into a TARDIS, the prototype of the sentient Type 102. (EDA: The Shadows of Avalon)

Copies of TARDIS technology
During the Doctor's second incarnation, the renegade Time Lord known as the War Chief provided similar time ships named SIDRATs to the War Lords to further the latter's plans of conquest. When they learned of this, the Time Lords placed the War Lords' planet in a time loop. (DW: The War Games)