“Voyager’s Return” is episode six of season one of Space: 1999.
Eagles 1 and 2 have been launched as an object is approaching Alpha. Main Mission is getting a signal; the probe says that it’s Voyager 1. Commander Koenig tells the Eagles to turn back. Alan says they’re under attack. Eagle 1 gets away; Eagle 2 is destroyed.
Eagle 1 is tumbling; Alpha has no communications with it. Alan comes around and straightens the flight then speaks to Main Mission, asking what hit. Koenig says it was the Quellor drive, explaining that it’s an atomic engine for crossing space at incredible speed. But, according to Paul, an engine that’s so dangerous that being inside a nuclear explosion would be safer. Victor has the details of Voyager 1. Launched 15 years ago to explore the galaxy, to find habitable worlds. He’s excited it’s returning. Paul, rather less so. One way or another the probe will destroy them and they’ve got to destroy it. Victor wants to download the information first. They’re got 11 hours and Eagle 1 is returning.
In the commander’s office, Victor tells the commander he wants the knowledge from the probe. Dr Russell would too, but it’s too dangerous. The commander suggests contacting Voyager’s computer and reprogramming it to use the chemical engines. The doctor is not convinced.
A younger man is telling an older one about Voyager 1. The younger asks if they learnt nothing from Voyager 2. They want to shut down Voyager’s drive. The older, Dr Linden, says they can’t do that. In Main Mission, Victor is trying to get the probe to delete its command file but it’s refusing when Linden enters. He calls the professor and the commander over. He warns them that what they are attempting to do must be very precise, or it will trigger Voyager’s destruct mechanism. Linden is asked how he knows. Because before he came to Alpha, his name was Quellor.
At a meeting, David tells the commander, Dr Russell, Victor, Paul and Alan that Quellor’s name was changed by Earth Command before he came to Alpha. Paul says that Voyager 2 killed out 200 people, one his father. The commander says they aren’t there to pass moral judgement, but to decide whether Linden can help. Can Victor guarantee he can shut down the Quellor drive? He can’t. Linden is called in; he says it’s theoretically possible to shut down the drive. 20 years ago, he would have guaranteed he could do it. Now, he will do his best. After Linden leaves, Koenig says he doesn’t want his real identity known. Not even by his assistant, Jim Haines, who lost both his parents.
Linden is talking to Jim, then Victor arrives to speak to Linden. The latter thinks he knows why the drive didn’t shut down when near an inhabited planet. In Main Mission, the commander checks with Sandra that the probe is being monitored, then with Alan how he plans to deal with it if they can’t shut down the drive. Basically, shoot at it a lot. The commander then checks to see how Linden is making progress.
Eagles are launched in case Linden isn’t successful. Linden tells Jim they’ve finally done it, they’re ready. Jim asks how they did it. Only one man had the knowledge to do what they have done. Ernst Quellor. He shoves Linden away, damaging the equipment and injuring Linden.
Linden still thinks he can do it, but they’re running out of time. And Voyager 1 is being followed by alien ships. It seems the stupidly dangerous Quellor drive – seriously, who thought something that deadly was a good idea as an engine? – wiped out a couple of planets. They are not happy.