“Black Sun” is episode ten of season one of Space: 1999.
In Main Mission, Paul wants details on an asteroid. Sandra says it will pass close, but David says there is nothing to worry about. Paul wants damage potential anyway. Then a collision alarm sounds and the commander comes out. The asteroid’s course has changed and it will now hit Alpha in a minute. But the asteroid diverts again, missing them and heading off into space where it explodes. Then Paul says they are changing course. A camera shows them heading towards a black disc.
Eagle 1 is being piloted by someone called Mike. Eagle 1 is normally Alan’s craft; it’s probably not going to end well for Mike. He says the disc is big, round and black. Eagle 1 is near where the asteroid was caught and can’t detect anything. It even swallows a laser. Communications with Alpha are poor, though there’s nothing wrong with the equipment. Mike wants to head in further using his screens to protect him, as Alpha is heading towards the disc. Victor, meanwhile, has proved something that computer says the commander needs warning about. Mike his heading in, but is running into problems when Victor arrives in Main Mission. Eagle 1 can’t pull out and explodes, and Sandra, who seemed to have a relationship with Mike, faints.
Victor tells the commander that if anyone is to blame, it’s him. He suspected hours ago. Commander Koenig states a black sun. Yes; they will all be dead in three days.
Victor briefs the staff and Paul asks if they can avoid it. Victor describes the black sun – which sounds awfully similar to a black hole – and afterwards Paul asks again. Victor did answer the question in his description.
Commander Koenig and Victor explain that they can’t avoid the black sun, but the eight antigravity towers that stabilise gravity on Alpha could help create a forcefield over Alpha. They’ll use the Eagle generators for extra power and turn off computer. The forcefield will attempt to reverse the pressure of the black sun, compelling the pressure of the black sun to protect them. Dr Russell thinks it’s ingenious. Victor says it’s insane.
The doctor asks Paul where the commander is. He’s outside with Victor, though he says to Victor they shouldn’t be. The forcefield is activated and Koenig orders Alan to attack. The attack bounces off.
Back in side, and the doctor tells them they were stupid. Victor says there was a 98% chance they would be safe. She asks about the other 2%. The commander says they would have just died one day before everyone else. The whole thing was for morale; they don’t really think it will work. Dr Russell asks what the point is. Victor says the same reason she doesn’t give up on a patient until they’re dead. After he’s gone, the commander says they plan to launch an Eagle as a lifeboat.
Victor finds David with the computer; David really doesn’t seem to think it should be shut down. The black sun is draining power, though, and they need all the power they have.
Paul tells the commander that they’re being pulled in faster than expected. Koenig says they need more time to launch the Eagle. Paul says the only way is to activate the forcefield now to get more time. Koenig wants to save power, but Paul tells him it’s Alpha or the Eagle. Koenig contacts Victor and tells him to turn it on. During which Victor gets electrocuted, but his mechanical heart saves his life.
The Eagle is loaded with supplies but it can’t take many people. Commander Koenig and Victor really don’t think Alpha can survive. But clearly something is going to happen.