Next: INTERIOR EXITS Up: TIMESHIP: EXTERIOR & INTERIOR Previous: THE DOOR LOCKING MECHANISM Contents
The defensive shield mechanism operates across the door area whilst the door is open. The shield is designed to separate the interior and exterior environments, preventing cross-contamination. In particular, interior air pressure will be maintained when the doors are opened in a near-vacuum such as outer-space. The shield may be discernable in that travellers walking through the doors may experience a pressure change. Such an environment change may be fatal, and it is recommended that atmospheric density jackets are worn are worn in extreme pressure conditions.
The lockjammer effect is the result of the intentional jamming of the ship's locking mechanism; it will not accept, release or allow any movement of the key, and it works it tandem with the secondary locking mode. When the lockjammer operates, the lock and key are effectively jammed, both are now useless. The purpose of this effect is that if any intruder tries to gain access to the TARDIS and fails, they will not be able to try again. The downside of this effect is that no-one can now enter the TARDIS, not even the proper owner.
The lockjammer device simply creates a low powered forcefield within the lock, by focusing the light beams through a set of small crystals. The light beams are usually used for identification of the key, but with amplification can be used to create a low powered force-field. The force-field ensures that the lock is impossible to activate.
If the locking mechanism becomes jammed or damaged then the TARDIS must be taken back to Gallifrey for repair. Most of the locking mechanism repairs can be carried out by the owner of the TARDIS if they understand the principles of the lock. However, great knowledge of the individual locking system in required. If the TARDIS keys are stolen, the whole locking system must be realigned and reset, and new keys cut to fit the new lock, as if the key has been stolen it may have been copied, and this allows the thief another chance to break in, thus violating Time Lord regulations. The ship provides a facility for cutting new keys; a key-cutter is pre-installed and is located in the central lobby. The machine has the ability to cut several shapes of key, all of which fit and operate the lock.