The Ark in Space is the second serial of the 12th season of the British science fiction television series Doctor Who, which was first broadcast in four weekly parts on BBC1 from 25 January to 15 February 1975. The serial is set more than ten thousand years in the future. In the serial, the insectoid aliens the Wirrn intend to absorb the humans along with their knowledge on board Space Station Nerva. Plot The TARDIS materialises on an aged space station. Sarah is overcome by lack of oxygen. While Harry and the Fourth Doctor explore, Sarah is transported away and placed into cryonic suspension by the station computer. Harry and the Doctor explore and realise the station is a kind of ark. Discovering Sarah, Harry searches for a resuscitation unit but discovers a mummified human-sized insectoid lifeform instead. A woman called Vira revives from suspended animation. Vira revives both Sarah and Noah, Space Station Nerva's leader. The Doctor tells Vira that Nerva's inhabitants have overslept by several millennia, thanks to the insect visitor that sabotaged the control systems. Noah and the visitors clash, and Noah accuses them of murdering a missing crewmate. Noah investigates the power room and is infected by an alien creature. The Doctor realises the alien insect laid eggs inside the missing crewman, who became an alien now inhabiting Nerva. Noah kills a crewmate, but recovers enough to order Vira to revive the remaining crew and evacuate, but the Doctor realises the alien pupae will mature too quickly for this. He proposes that they destroy the Wirrn while they are in their dormant, pupal stage. Dissection of the Wirrn corpse reveals the Wirrn are vulnerable to electricity. As he tries to reactivate the station power, the fully transformed Noah attacks him. Noah reveals that the Wirrn were driven from their home by human settlers and now intend to absorb all human knowledge. The Doctor plans to electrify the cryogenic chamber to prevent the Wirrn from attacking more of the human crew. Because the Wirrn have disabled the station's power supply, the crew decide to use the generators on board a transport ship docked at the space station. Sarah volunteers to crawl through a narrow conduit carrying the power cable from the ship, and the Doctor succeeds in electrifying the cryogenic chamber. Set back, Noah, as the Swarm Leader, offers the others safe passage from Nerva if they