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 Dimensions In Space". (DW: An Unearthly Child)


 * It was once indicated that she gave the Doctor the idea of the acronym when he was possibly the Other. (NA: Lungbarrow)

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 surposed 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) The "dedication plaque" in the Doctor's TARDIS referred to the ship as "Time and Relative Dimension in Space", favoring the singular form, (DW: Amy's Choice) but dimensions, makes gramatical sense.

Flight
TARDISes most often moved through time and space by "disappearing here and reappearing there" (DW: Rose), a process known as "de- and re-materialisation". This was controlled by a unit known as the dematerialisation circuit (DW: Terror of the Autons). They were also capable of flying through space like a conventional spacecraft, but doing so for prolonged periods could result in damage to the ship (DW: The Runaway Bride).

During flight, a distinctive grinding and whirring sound is often heard (DW: An Unearthly Child onwards). According to River Song, TARDISes are capable of materialising silently, the noise actually being caused by the Doctor leaving the brakes on during materialisation (DW: The Time of Angels). However, River may simply have been joking, at least about the brakes—other TARDISes seen in the show made the same sound in the course of their normal operation, and the Minyans' computer in DW: Underworld recognized the sound. Some fans theorize that leaving the brakes on may be to aid a singular Time Lord essentially flying a six-pilot ship, giving them more time to react, and that the Doctor did not realise that anyone could fly a TARDIS on their own without leaving the brakes on.

This sound has also been made by several other things; for example, at the end of DW: The Three Doctors, the Time Lords provided the Doctor with a new dematerialisation circuit which appeared on a table making this sound (since this is the part of the TARDIS which controls its materialisations, it may have been operating under its own power). The Doctor also modified Skagra's invisible spaceship to fly like a TARDIS and, again, this sound was heard (DW: Shada).

When a TARDIS materialises, it can sometimes result in strong wind and small tremors (enough to shake wine glasses) in the area in which it appears (DW: Love and Monsters, Smith and Jones, The Eleventh Hour,The Big Bang) This is most likely a side-effect of the TARDIS pressing itself into that particular area of space and time.

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 Doctor, while working for the Celestial Intervention Agency, was briefly assigned a Type 97 TARDIS. (PDA: World Game) The fifth incarnation of the Doctor once remarked that he should have upgraded to a Type 57 TARDIS. (DW: Warriors of the Deep) On another occasion, he noted that a Type 70 would allow him to break through a temporal distortion grid, but that his Type 40 was not cut out for such a "brute force approach". (BFA: Singularity) In his eighth incarnation, he encountered the Type 102, that appeared to be a near-Human. (EDA: Alien Bodies)

By 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
One of the key features of a TARDIS was that the interior existed in a 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: An Unearthly Child, et al)

The Doctor once explained the phenomenon by using two boxes, one smaller than the other, and placed the bigger of the boxes down and moving away from it so that the big box looked as if it could fit within the small box. Saying that if the big box could be accessed from the small box it would be bigger on the inside and that once they realized that it was a small feat making them bigger on the inside than the outside suggested.

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. This theory is further substantiated when the doctor enters the Monk's TARDIS and changes its appearance from a pillar of stone to a police box identical to his own TARDIS (DW: The Daleks' Master Plan). ''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 sapience, and could take independent action, such as when the Doctor's TARDIS resurrected Grace and Chang Lee (DW: Doctor Who (1996)), or someone – including 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 the average TARDIS is alive, and whether that life extends beyond artificial sapience and into a biological existence. Some more-advanced TARDISes, such as Compassion, have been fully-sapient beings in their own right.

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) In at least one case, the Doctor's TARDIS manifested an avatar to help him fight a mental battle, taking on the forms and personas of the various companions who had ridden within it – however, this was when the Doctor was in fact unconscious and was battling within his own mind. (IDW: The Forgotten).

A living TARDIS also had the capacity to become a Paradox Machine, something the Doctor described as 'cannibalism'. The Master built such a machine to sustain the paradox created when the Toclafane came back in time to kill their human ancestors. (DW: The Sound of Drums.

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. (DW: The Deadly Assassin) Following the events of the Last Great Time War, the Doctor believes that his is the last TARDIS in existence, (DW: Rise of the Cybermen) and is therefore protective of it.

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, the only one of that type, with the first generation of mass produced sentient TARDISes being the 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)

When the Skith probed the Doctor's mind they gained knowledge of the TARDIS and made their own version, the SKARDIS. (DWM: The Age of Ice)

When the Daleks gained time travel, they made a similar version of the TARDIS, the DARDIS. (DW: The Chase)

Number 79B, Aickman Road was a copy of TARDIS technology (DW: The Lodger)

Behind the scenes

 * Although TARDIS is correctly spelled in all-caps as an acronym, it is common for it to appear as Tardis in novelisations and original novels, TV listings, media reports, etc. In dialogue, the word is almost always used in the context of "the TARDIS" (referring to the Doctor's capsule) or "a TARDIS". An exception to this is the two Peter Cushing films, in which it is simply referred to as "Tardis" (with the lower-case implied).
 * On the sets for the TARDIS for Christopher Eccleston, David Tennant and Matt Smith there is a plaque saying the make model and chasis number of the TARDIS.