Соңтар эксперименті: Жердегі сынақтар мен қауіп

The Sontaran Experiment is the third serial of the 12th season of the British science fiction television series Doctor Who, which was originally broadcast on BBC1 on 22 February and 1 March 1975. The serial is set on Earth more than 10,000 years in the future, immediately after the events of The Ark in Space. In the serial, the Sontaran Field Major Styre (Kevin Lindsay) performs experiments on humans he trapped there as part of the Sontarans' invasion stratagem.

Following on from The Ark in Space, the Fourth Doctor, Sarah Jane Smith, and Harry Sullivan teleport down from the Nerva space station to Earth, ostensibly uninhabited. However, the system is not functioning well, and the Doctor begins repairing it. The other two explore the surrounding area, but Harry falls down a crevasse and Sarah goes to seek the Doctor's help. He is nowhere in sight. Roth, an astronaut, finds Sarah. He is obviously distressed, and explains that he has been tortured by an alien that lives in the rocks, together with its patrolling robot. He takes Sarah towards the astronauts' campsite, but refuses to approach it, suspecting the astronaut Vural of collusion with the alien. Three of the astronauts have captured the Doctor. They believe Nerva to be a legend, and tell him in turn that they had picked up a distress signal from Earth. They came to investigate, but their ship was vapourised when they emerged, leaving nine of them stranded. Then they began to vanish one by one. They blame the Doctor for this. Roth appears and the astronauts chase him, while Sarah frees the Doctor. Roth loses the others and meets up with Sarah and the Doctor. The Doctor also falls down a crevasse, and the robot returns, capturing Roth and Sarah and bringing them to the alien's spacecraft. The alien is Field Major Styre of the Sontaran G3 Military Assessment Survey, who has been experimenting on, and killing, the astronauts. Roth tries to escape but is shot dead by Styre. Styre reports back to his Marshal via a video link. The Marshal is impatient for the intelligence report (without which an invasion of Earth cannot take place), but Styre admits that he has been delayed in his experiments. Styre subjects Sarah to a series of terrifying hallucinations. The Doctor, free from the hole, has reached her and rips off a hallucinogenic device from her forehead, but she falls unconscious. The Doctor, enraged, attacks Styre, but the Sontaran easily fends him off. Styre shoots him unconscious (believing it to be fatal) when he runs away. The robot, having captured the three remaining spacemen, brings them to Styre's ship, where it is revealed that Vural had tried to make a deal with Styre in exchange for his own life. However, Styre intends to experiment on Vural anyway. The Doctor recovers, disables the robot, and meets Sarah and Harry. He confronts Styre, goading him into a hand to hand combat. While they fight, Sarah and Harry free the astronauts, and then Harry climbs towards Styre's ship to sabotage it. Styre almost wins the fight, but Vural attacks him, saving the Doctor at the cost of his own life. Styre, now low on energy, heads back towards his ship to recharge, but the sabotage causes it to kill him. The Doctor informs the Marshal that not only has Styre's mission failed, but that the invasion plans are in human hands. This is enough to ward off the invasion, and the three can return to Nerva, or so they think.

Working titles for this story included The Destructors. These two episodes were initially part of a six episode arc, but Philip Hinchcliffe made the decision to split the arc into the four part Ark in Space and this two part story, sharing the same director and budget. To save money, Hinchcliffe decided that Ark would be entirely recorded in the studio and this story would be entirely recorded on location. He also settled on the Sontarans because they could re use the Sontaran costume from The Time Warrior and therefore save the expense of designing a new alien. This was the first two part serial to be broadcast since 1965's The Rescue and the last until 1982's Black Orchid. Although the serial was the third to feature Baker, it was actually the second shot, hence the out of sequence production code. This was only the second serial in the history of Doctor Who (the first being 1970's Spearhead from Space) to be shot entirely on location, in this case at Hound Tor on Dartmoor. However, unlike Spearhead from Space and the location material for other serials, the production was mounted entirely on videotape using early portable video equipment, rather than on the usual 16mm film. This use of location video was remarkable for the time, but technical problems are evident in the final programmes. This was also the first and only Doctor Who story where there were no interior scenes at all. During shooting, Baker broke his collarbone. However, because part of his costume was a large scarf, he could conceal the neck brace he had to wear following the injury. For action scenes, he was doubled by regular stunt performer Terry Walsh, shot from several face concealing angles. The recording of both episodes was completed in a week.

Glyn Jones, who played the astronaut Krans, wrote the First Doctor serial The Space Museum (1965); he was the only person both to act and write for Doctor Who during its original 1963 89 run. The Sontaran Experiment contains the last major role played by Kevin Lindsay before his death in 1975 of a heart condition.

A novelisation of this serial was written by Ian Marter, who appeared in the serial as the Doctor's companion Harry. It was published by Target Books in November 1978. The novelisation differs from the TV version by having the travellers arrive in the TARDIS. The Sontaran plan here does not involve war with the Rutans but a planned conquest in alliance with another clone species.

The Sontaran Experiment was released on VHS in October 1991 as a double video with Genesis of the Daleks. In October 2006, it was released on DVD on its own or part of the Bred for War box set, along with The Time Warrior, The Invasion of Time and The Two Doctors.