Doctor Who (1963–1989)
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The Ark in Space: Part Three 

Knowing that Noah has been infected by the Wirrn, the Doctor persuades Vira to halt the reviving of her people, knowing it will place them in danger as well.




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Episode complete credited cast:
Wendy Williams ...
Richardson Morgan ...
John Gregg ...
Gladys Spencer ...
High Minister (voice)
Wirrn Operator


Knowing that Noah has been infected by the Wirrn, the Doctor persuades Vira to halt the reviving of her people, knowing it will place them in danger as well.

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Release Date:

8 February 1975 (UK)  »

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Technical Specs

Sound Mix:


Aspect Ratio:

1.33 : 1
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Did You Know?


This episode takes place on the Nerva Beacon in 16087. See more »


Doctor Who: Absorbed? "We shall absorb the humans"? Endoparasitism?
Sarah Jane Smith: [to Vira] He talks to himself sometimes because he's the only one who understands what he's talking about.
See more »

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User Reviews

Fantastic sci-fi claustrophobia and parasitic alien attacks on humans - a classic forerunner of Alien.
18 November 2014 | by See all my reviews

Review of all 4 episodes:

Whether there is a direct influence from this on Ridley Scott's 'Alien' I do not know but either way it clearly foreshadows ideas seen in that film. It has humans in stasis for space travel, a claustrophobic atmosphere on a space vessel under attack, 'body horror' as aliens attack humans parasitically and a strong and intelligent female crew member taking a lead role. It is striking how this story has many similarities with that famous film which came a few years later and all those similar aspects are really good ones.

This story is top notch Doctor Who. It is intelligent, very entertaining, sometimes very funny, sometimes very scary (particularly for children), atmospheric and exciting with brilliant scripts and acting.

The Doctor, Sarah Jane and Harry arrive by accident on the space station Nerva which is an Ark of human knowledge, Earth history, culture and life. It contains specially selected representatives of the human race sleeping in stasis and being sent out from Earth at a time when the planet was threatened by solar flares. The time in stasis has gone way longer than intended (10,000 years) due to the station being attacked and sabotaged by an alien creature. This creature is a giant insect called a Wirrn. It has laid larvae on board and the Wirrn are multiplying and attacking with the intention of absorbing the humans and gaining all human knowledge into their collective intelligence. The human leader is touched by a Wirrn larvae and begins to slowly metamorphosise into a Wirrn.

The space station set is superb and the production in general makes the best of cheap effects. The story itself is interesting and thoroughly good quality throughout. The characterisation of the guest characters is excellent with the convincing acting and clever characterisation of 'Noah' who is being gradually taken over by the alien parasites well as the aforementioned strong female guest lead character (which in addition to the wonderful Sarah Jane gives us two top class female roles), and technician Rogin.

This is a top class story and a true classic with Tom Baker really establishing himself as an incredibly good Doctor in only his second story.

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