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The Ark in Space was the second serial of season 12 of Doctor Who. It was the Fourth Doctor's first full, post-regenerative story. It proceeded from a mild-cliffhanger at the end of Robot, showing what happened after Harry Sullivan climbed into the police box in UNIT's laboratory. It importantly established the location of Nerva Beacon, which would be the narrative lynchpin of the season.

The Ark in Space had a somewhat tortuous scripting process, having slipped past two writers before its scripts were finally accepted. Both Christopher Langley and John Lucarotti tried and failed to write a script about a space station for season 12. Of the two, Lucarotti came closest. However, because he then lived on a boat anchored in the Mediterranean — and there was a postal strike afflicting Corsica — Lucarotti was essentially incommunicado to script editor Robert Holmes. It was impossible for Holmes to conduct timely consultation with the Doctor Who veteran. Lucarotti was paid fully for his work, and Holmes undertook a page one rewrite, retaining only the central concept of Lucarotti's tale. (INFO: The Ark in Space)

Despite its difficult birth, the story won kudos from the BBC Wales production staff. Russell T Davies once called The Ark in Space his favourite storyline of the 1963 version of Doctor Who, (DOC: Inside the World of Doctor Who) and Steven Moffat considered it the best Fourth Doctor story, (REF: DWM 457) while Barnaby Edwards confessed to being "petrified of the Wirrn" as a child. (CON: Do You Remember the First Time?) Tom Baker himself has also stated that, of all the stories he'd filmed, The Ark in Space was his favourite.

It was a particularly popular serial with contemporary audiences, as well. Part two, in fact, was the fifth-most-watched programme of its week, making it the highest-charting episode of the original version of the programme. In fact, it retained its crown until the transmission of Voyage of the Damned, which was the second-most-watched programme of its week.

From a production standpoint, it was the first story produced by Philip Hinchcliffe, the new producer after Barry Letts departed from the show. He established a new, darker and ostensibly "Gothic" style of storytelling during his time as the producer of Doctor Who, although this particular story only demonstrated the former trait, being more in the genre of the 'space opera horror' later popularised by Alien. Notably, a much later TV story, would inadvertently find itself mimicking a contemporary of the same genre.


The TARDIS lands on a space station orbiting Earth in the distant future. It's seemingly deserted, but the Doctor, Sarah and Harry soon discover that they are not alone. Thousands of humans are in cryogenic sleep, and while they've slept their Ark has been invaded. A parasitic insect race, the Wirrn, have taken control and threaten the very future of mankind.


Part one[]

An unseen presence approaches a space station orbiting Earth and silently infiltrates it. It reaches a human apparently asleep and unaware...

The Doctor and Harry take a look around.

The TARDIS materialises in a dark and stuffy room aboard an apparently unmanned station, due to Harry's inadvertent interference with the helmic regulator. Once the Doctor turns the lights on, the TARDIS crew decide to look around. Harry presses another switch, unknowingly trapping Sarah in a small control room where the oxygen is rapidly being consumed. By the time the Doctor and Harry find her, she is severely cyanosed. They then find themselves trapped with her. The Doctor repairs the oxygen servos just in time to save them all. He notices that the control cables have been bitten clean through.

As Sarah recovers on a nearby couch, the Doctor and Harry are attacked by an automatic sentry system which fires electronic bolts at any moving organic object, including people, a cricket ball and the Doctor's scarf. Meanwhile, Sarah is transported from the couch on which she is resting, and into a chamber where she hears two voices preparing her for a "journey".

The Doctor and Harry deactivate the auto guard by distracting it with Harry's shoes and discover that Sarah has vanished. Exploring further into the station, they encounter a slime trail in the corridor but continue into a restricted section holding hundreds of cryogenically suspended humans, along with animal and botanical specimens and an information store. Harry opens a berth and finds Sarah in suspension. He begins looking for a resuscitation unit to revive her and opens a cupboard — only to encounter a giant insect which lurches at him...

Part two[]

Nerva's first crew member revives.

The insect falls to the floor, obviously dead for a long time. The Doctor finds a medical kit but is unsure of how to use it. One of the sleeping pallets activates, and the occupant takes the medkit and sleepily uses it to revive herself fully. She introduces herself as Vira, First Med-tech, and demands to know what the TARDIS crew are doing aboard. She agrees to revive Sarah when she realises her suspension was an accident. Vira explains that solar flares were threatening to destroy Earth's ecosystem and that the government put a select group of humans in suspension on Space Station Nerva, so they could repopulate the Earth after five thousand years. She is astonished when the Doctor informs her that she has "overslept" by several thousand years because of the alien's sabotage. While she tries to revive the station commander, Lazar, or "Noah" as he is known, the power fails again.

The Doctor goes down to the station's infrastructure to effect repairs and sees a large, green grub in the solar collector, feeding on the solar energy. Noah revives and demands the TARDIS crew be removed before they contaminate the genetic pool. He arms himself and proceeds to the control room, where he stuns the Doctor. Vira notices that Dune, the station's chief technician, is missing from his pallet. Noah ascribes this to the "regressive" interlopers. He enters the infrastructure to look for any damage the Doctor may have done but is accosted by the grub, which touches his hand and renders him unconscious. Harry and Sarah find and wake the Doctor, only to be escorted back to the cryogenic section by Noah, who keeps his hand firmly tucked out of sight in his pocket.

As they return, Vira is reviving Libri, a young technician, who is instantly afraid of Noah when he first sees him. The commander begins to act erratically and insists the revivals be halted and that Dune is not missing, stating, "I am Dune", before storming out. The Doctor convinces Libri to go after Noah and stop him. He then proceeds to examine Dune's cryogenic pallet. He finds membrane from the alien queen's egg sac and concludes that the queen laid her eggs in Dune's body before she died, and the alien larvae have absorbed Dune's knowledge along with his body. Libri, meanwhile, finds Noah in the control room but cannot bring himself to shoot his commanding officer, who kills him before bringing his hand slowly from his pocket. He has started to metamorphose into an alien being.

Part three[]

The voice of the Earth High Minister comes over the station's P.A. system to deliver a rousing recorded speech for the awakening colonists, while Noah tries to fight the alien presence in his mind. He contacts Vira and transfers command to her, ordering her to get the sleepers revived and down to Earth as soon as she can. Before he loses control, he says the aliens are called the Wirrn and states, "We shall absorb the humans."

The Doctor and Vira go in search of Noah, leaving Harry and Sarah to revive two more crew members, Rogin and Lycett. Noah, more fully absorbed by the Wirrn, meets the Doctor and Vira in the main corridor and explains that the larvae are approaching adulthood. Vira takes what is happening to Noah very badly; the commander and she were "pair-bonded" for the colonisation.

Harry and the Doctor perform a brief autopsy of the queen and discover the Wirrn are a space-borne species. Vira begins to initiate the next phase of revivals but the Doctor convinces her to delay while he develops a plan to stop the Wirrn. Using the Ark's technology, he links his mind to the queen's neural cortex, experiencing her last few memories. Meanwhile, a grub breaks into the cryogenic chamber and kills Lycett. Harry and Rogin run to the armoury for fission guns, narrowly avoiding Noah, and drive the grub back into the air duct with the Doctor's help. The Doctor has learned that the queen was killed by the auto guard and decides to electrify the walls of the cryogenic section. He transmats Rogin and Harry to the control room before the power fails again and realises that the Wirrn must be pupating into adults. He goes down to the infrastructure to turn the power back on, but Noah has almost become an adult Wirrn and advances on the Doctor. The only thing that remains human about him is his face, and this then fades away to be replaced by the features of the Wirrn.

Part four[]

Vira appears at the top of the stairs and fires her stun gun at Noah, allowing the Doctor to get clear. Noah asks Vira to stay and listen to his proposal. If she and the awakened crew-members take the station's shuttle, he will order the swarm to let them go. The Wirrn will absorb the remaining sleepers and become a technologically advanced race, like the human pioneers who displaced them, centuries before, from their homeworld in the Andromeda Galaxy.

Vira refuses to abandon the Ark, and the crew try to come up with a way to ensure power will reach the Doctor's electric bulkheads. Sarah suggests the shuttle Noah mentioned and volunteers to carry a power cable through the service conduits to the cryogenic section.

Noah, now almost entirely a Wirrn, holds the station hostage.

As she proceeds past the Wirrn, they try to stop her and the shuttle crew from performing their tasks. Two Wirrn are repelled by a test burn from the shuttle's engines. Sarah gets stuck in the conduit and the Doctor uses reverse psychology, complaining that she is useless in an emergency and not nearly as tough or resourceful as she thinks she is, to help her get through. Sarah fights her way free, only to realise she has been "conned" by the Doctor. The electricity keeps the Wirrn at bay, but Noah threatens to turn off the oxygen, which the Wirrn don't need.

The Doctor tries to remind Noah of his human past and urges him to lead the swarm back into space where they belong, but Noah claims "I have no memory of the Earth." The entire swarm breaks into the shuttle's cargo hold and tries to reach the bridge. Vira sets the controls for automatic take-off and disembarks, while Rogin and the Doctor remove the synestic locks that hold the shuttle down. Rogin sacrifices himself by removing the final lock. He is killed by the shuttle's exhaust. As the Doctor wonders if Noah led the swarm aboard the shuttle on purpose, Noah radios the station and says goodbye to Vira before sabotaging the shuttle, making it explode in space and proving his humanity had won. Vira vows to get the sleepers revived and down to Earth, but without the shuttle they will have to rely on the transmat. The Doctor, however, notices that the transmat receptors on the ground are faulty and volunteers to beam down with Harry and Sarah to fix them. After they have done so, Vira smiles — the first human emotion she has shown — and then returns to her duties.


Uncredited cast[]


Uncredited crew[]



Foods and beverages[]



Story notes[]

  • The story's working title was Ark in Space (without the "The"). This was also the title given in Radio Times for the 69-minute compilation repeat of the story, as first broadcast Wednesday 20 August 1975. The Australian VHS release of the story in January 1989 also uses the title Ark in Space.
  • In part one, the opening title sequence was tinted pink and green, making it appear brown rather than the usual blue (even the light on top of the TARDIS is brown). This colour tint was never used again.
  • The Nerva sets are reused for Revenge of the Cybermen.
  • The whole story bears resemblance to the Ridley Scott film Alien released in 1979.
  • It is only mentioned once by Vira, but Noah's real name is Lazar; "Noah" being a joke on his role on Nerva.
  • Aside from an extra, Brian Jacobs, as Technician Dune; and two voice-over artistes, Gladys Spencer and Peter Tuddenham, no-one but the regular cast appears on-screen in part one. This had not occurred since The Edge of Destruction aired in the show's first season and would not happen again.
  • Vira was written to be black and possibly Haitian, but this was changed by the director.
  • The original script was written by John Lucarotti and he was paid for his work; however, script editor Robert Holmes had to do extensive revision and received the on-screen writer's credit. Lucarotti's storyline included an Ark, an uninhabitable Earth, humans who had overslept and aliens who had entered the Ark in the meantime. Noticeable differences include the race of the aliens and that the Doctor went to the Ark intentionally. Lucarotti's aliens, named the Delc, had the ability to replicate instantly. This would have been Lucarotti's fourth script for the show and his first since the William Hartnell era.
  • John Lucarotti had given the story individual episode titles, not realising the use of these had been discontinued after The Gunfighters. The episodes were named "Buttercups", "Puffball", "Camellias" and "Golfball".
  • Elisabeth Sladen is credited as "Sarah Jane" in Radio Times for part two.
  • Gladys Spencer is credited alongside Peter Tuddenham as "Voices" for part one, and as "High Minister's Voice" for part three.
  • The 69-minute compilation repeat of the story was heralded by a small Radio Times article entitled Encore, Dr. Who, which was published alongside the programme listings for Wednesday 20 August 1975. This read as follows: "When Ark in Space was first shown earlier this year, it got the best viewing figure ever for a Dr. Who story. Now it's being reshown as one 70-minute programme (6.35 BBC1); and it's only two more weeks until a new Dr. Who series begins with a story set around Loch Ness — and with a RADIO TIMES feature." (original published text)
  • Christopher Masters (Libri), John Gregg (Lycett) and Peter Tuddenham (Voice) were uncredited on-screen for the 69-minute compilation repeat of the story, though they were credited in Radio Times; while Gladys Spencer (High Minister's Voice) was omitted entirely from the finished programme. The Radio Times programme listing was accompanied by a black-and-white illustration by Frank Bellamy depicting the Doctor, Space Ark Nerva, a Wirrn, and one of the Cryogenic Chamber's upright sleeper pallets, with the accompanying caption "Dr. Who (Tom Baker) explores the intergalactic threat to the human survivors aboard the Ark in Space: 6.35". (original published text)
  • This is the last non-season opener to introduce a new producer.
  • There was originally a scene where, in the final stages of larval infestation, Noah's head splits open and cracks in a torrent of acidic goo, that was cut because it was too graphic. There are conflicting reports on if the scene was ever filmed, and if it was, the scene was lost.
  • A scene was filmed where Noah confronts Vira and begs her to kill him to end his agony, which Philip Hinchcliffe decided to cut as it was too dark. The scene in the aired episode cuts from a shot of the Doctor looking on to a shot of him glowering and looking harrowed from a similar angle in a different room, with the door shut and no indication how they got away from Noah. Kenton Moore, who played Noah, expressed his opinion that he was furious about the scene going because it was crucial to the whole story. The missing scene is lost.
  • In the original script, the conclusion of part four had the Wirrn going off into the depths of space, having been led away from Space Ark Nerva by the fully transformed Noah — an ending presumably written by Robert Holmes to allow for a possible sequel to the story. However, the BBC feared that the possibility of the Wirrn surviving would frighten younger viewers, forcing Holmes to kill them off instead.
  • Robert Holmes thought that the Wirrn looked like a "knackered Muppet".
  • The serial was repeated on BBC Four, as part of its "Science Fiction Britannia" season in 2006. Parts one and two aired on 27 November; and parts three and four on 4 December.


  • Part one - 9.4 million viewers
  • Part two - 13.6 million viewers
  • Part three - 11.2 million viewers
  • Part four - 10.2 million viewers

Filming locations[]

Production errors[]

If you'd like to talk about narrative problems with this story — like plot holes and things that seem to contradict other stories — please go to this episode's discontinuity discussion.
  • During the first episode, when Sarah Jane is trapped in another room, Harry asks "Is she in the TARDIS?" The Doctor responds "Impossible, I've got the key." However, if you look close, the door to the TARDIS can be seen as cracked open slightly.
  • There is a piece of very poor editing done when the half-mutated Noah confronts Vira and the Doctor as they move along the corridor (probably done to remove the more grotesque aspect of the scene). Noah is still talking and then somehow the door slams shut, cutting him off. Yet it is not clear who does this or what exactly happened. A part of this scene, in which Noah asks Vira to kill him before he turns completely into a Wirrn, was cut because it was felt it might be too disturbing for children.
  • Just before Noah shoots Libri, as he says, "You fool, Libri", a crew member can clearly be heard coughing.
  • The Wirrn falling out at the first cliffhanger interrupts the Doctor talking — but he's not talking at the start of part two. Actually, he's talking in both, but his lines fade out more in part two. In both cases the Doctor is not watching Harry open the cupboard, so he has finished speaking when the dead Wirrn crashes to the floor.
  • One of the frozen humans can be seen blinking.
  • When the Doctor and Harry move the screwed-in table there are no mounting holes for the screws to go in.
  • The space station noticeably "wobbles" as it orbits above Earth in the opening shot.
  • The empty chamber that held Dune is tinted or stained orange-yellow in part two, but it was the same colour as the others in the previous episode. The individual capsules light up when the revival process starts, but since Dune is absent, the red light indicates some kind of fault.
  • When Vira climbs out of the cryogenic capsule, the styrofoam comprising the capsule squeaks.
  • The "holes" in the floor, probably meant to evoke the drainage holes (scuppers) in a ship's deck, can be seen to be painted on when the Doctor detaches the table.


Home video and audio releases[]

DVD releases[]


  • Commentary by Elisabeth Sladen, Philip Hinchcliffe and Tom Baker
  • New CGI Model Sequences - Choose to watch the story with the original space-station model shots replaced by new computer-generated effects.
  • Unused Title Sequence
  • Original Model Effects
  • Trailer for Episode 1
  • Photo Gallery
  • Who's Who
  • Space Station Schematics
  • Howard Da Silva Intros (Region 1 only) - Continuity announcements by Howard Da Silva, included in the 1978 Time/Life distribution of The Ark in Space to North American television stations.
  • TARDIS-cam
  • Interviews with Roger Murray-Leach and Tom Baker
  • Production Subtitles
  • Easter Egg - 16-second spot featuring Tom Baker promoting the Doctor Who Exhibition Blackpool. To access this hidden feature, press left at Tom Baker Interview on the Special Features menu. Another promotional spot for the exhibition appears after the closing credits of Part Four. (On the Special Edition DVD release, press left at Photo Gallery on the Special Features menu.)
  • Easter Egg - 30-second shot of a production clapperboard used for Part Two of The Ark in Space. To access this hidden feature, press up at Part One on the Episode Selection menu.


  • Region 1 (special edition) 2013


  • The original release back-cover contains a typing error which states that the serial started airing on 23 January when it actually started on 25 January.
  • Editing for the DVD release was completed by the Doctor Who Restoration Team.
  • Viewers have the option of replacing the model shots with new CGI effects.
  • As with many serials released on DVD pre-2006, The Ark in Space was subsequently re-released as a special edition, with additional content:
    • A New Frontier: Making The Ark In Space
    • TV Movie Version: Special 70-minute compilation of the story.
    • Doctor Forever!- Love & War, Documentary examining the Virgin/BBC novelisation range with Russell T.Davies and Mark Gatiss.
    • Scene Around Six
    • 8mm Location Footage from Tom Baker's first story
    • Radio Times Listings, Doctor Who Technical Manual, Crosse and Blackwell and Nestlé promotional material in Adobe PDF format.

Digital releases[]

This story is available:

  • in non-continental iTunes stores (Australia, Canada, the UK and US) as a stand-alone story;
  • on Amazon Video (UK) as Season 76 of Doctor Who (Classic) series;
  • for streaming through BritBox (US) as part of Season 12 of Classic Doctor Who.

VHS releases[]

This story was released on VHS in compilation form in Australia and the UK in 1989 in PAL format (BBCV 4244), though the Australian release was several months prior to that in the UK. The Australian release was titled Ark in Space, and the sleeve credited Elisabeth Sladen and Ian Marter as well as Tom Baker.

The story was re-released in "Complete & Unedited" (i.e. episodic) form in 1994.

Laserdisc releases[]

  • This story was released in episodic form on Laserdisc by Encore Entertainment in 1996.

Audio releases[]

Excerpts from Dudley Simpson's score, arranged by Heathcliff Blair, were released by Silva Screen in the early 1990s on their compilation CD Pyramids of Mars: Classic Music from the Tom Baker Era (FILMCD 134).

External links[]