In the 2005 relaunch of Doctor Who, first season, the TARDIS was revealed as having a forcefield, which can stop the laser beam of Daleks.

In episode 13, it does stop the attack of Daleks when the doctor stepped outside of the TARDIS.

Although the doctor said the forcefield can stop anything, Jack Harkness said it can stop almost anything. So it means something can break the forcefield.

So when did the TARDIS start having a forcefield?

If it does not contain spoiler (I am watching the 2nd season, 3 episode), what is the thing that can break the forcefield?

3 Answers 3


The Doctor's TARDIS has probably always had a force field generator.

As far back as the 3rd Doctor there was mention of the force field. In The Three Doctors, the 3rd Doctor's exile to Earth is lifted as thanks for his help against Omega, and he explains that he will stay on Earth, so that he can repair it. It's mentioned again at times, for example, in the 5th Doctor's Four to Doomsday, where it protects the Doctor from outer space when the TARDIS door is open.

At some point between then and the 9th Doctor, the force field apparently ceases to work (the Doctor's TARDIS has never been in good shape). In The Parting of the Ways, Captain Jack Harkness used a tribophysical waveform macrokinetic extrapolator to create a force field around the TARDIS, and we see this integrated into the TARDIS console itself.

Although the force-field can protect the TARDIS against many threats, we do see that

the Dalek Crucible in Journey's End is capable of destroying the TARDIS, although it has been disabled, so perhaps the force-field was simply not in effect.

Out-of-universe, I expect that Captain Jack's comment was a hedge by the writers so that they were justified in having something threaten the TARDIS in later episodes.

When the 10th Doctor regenerates into the 11th,

the violence of the regeneration causes significant damage to the TARDIS interior. When we see it repaired/remodelled, the extrapolator is no longer visible. However, we do see force-field effects with the 11th Doctor's TARDIS, so either the extrapolator is merely no longer visible, or perhaps the original force-field generator was repaired along with the rest of the TARDIS.

  • 1
    The forcefield must still be there, as the 11th Doctor has opened the TARDIS doors several times while it's out in space.
    – user1027
    May 15, 2011 at 15:15
  • 3
    @Keen: he called that an "air shell" in The Beast Below
    – Nick T
    May 15, 2011 at 21:10
  • 2
    BTW: The Force Field is there in the latest episode The Doctor's Wife.
    – Richard
    May 16, 2011 at 6:30
  • 1
    @gunbuster: it can only extend a few feet beyond the TARDIS.
    – Jeff
    Jun 6, 2011 at 12:21
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    @Tony: He extended it just beyond the TARDIS so he could talk to the God of the Daleks in the first episode where he integrated it into the TARDIS. When they shoot (I believe, don't have it handy) you can see the field.
    – Jeff
    Jun 8, 2011 at 0:35

It is called an Tribophysical waveform macro-kinetic extrapolator. The Doctor got it from the last of the Slitheen family on Earth in the episode 'Boom Town'. He and Jack Harkness and integrated it into the TARDIS at that point.

The previous 'Air Field' served only to keep atmosphere (and pressure) in a vacuum. It had no capability to resist weapons fire.

When last seen, it was covered in the coral the TARDIS is made from, which indicates to some that it is being absorbed and integrated more directly into the TARDIS.

  • It could be argued that the TARDIS no longer possesses this force field after it "regenerated" in "The Eleventh Hour", or after it and the rest of the universe rebooted in "The Big Bang". Feb 19, 2013 at 15:29

FYI - In addition to the force fields and other safety measures, the TARDIS features the HADS, or Hostile Action Displacement System. If faced with an attack that could cause sufficient harm to the ship, the TARDIS can automatically take off and land a (supposed to be) short distance and time period away. It was used correctly in the original series adventure The Krotons, and malfunctioned in Cold War, sending the ship to the other side of the planet, several hours after its takeoff.

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