“Space Brain” is episode twenty-one of season one of Space: 1999.
Commander Koenig finishes a jigsaw in his office, then opens the door to Main Mission, telling Sandra and Paul he’s turning in. It seems he’s set a new record for the jigsaw. On the way to his quarters, the commander hears a sound. All the comms are displaying gibberish on the screens but are otherwise non-functional.
Returning to Main Mission, the commander is told by Paul that it’s coming in on every channel. The staff arrive and Sandra has tracked the origin. The commander tells Alan to launch the standby Eagle. The Eagle approaches the source, which the pilot describes as being like an anemone. The Eagle is being wrapped with something and they lose communications with it. Whatever was trying to talk to them has also stopped and the commander tells Alan to take a rescue Eagle.
Something passes the Eagle as it’s heading out and then passes through Alpha’s defence screens. A meteorite covered in strange strands lands near Alpha. An Eagle collects the rock for analysis and there’s still no communication from Eagle 1. David says the rock came from near where Eagle 1 was last detected. Koenig tells Alan to look out for wreckage. Sensors aren’t working well, so the co-pilot, Kelly, will do a spacewalk to look.
Victor is examining the rock when the commander arrives. It’s very dense and very heavy; computer is calculating both. Dr Russell is telling the commander that the material on the outside when Victor interrupts. He has the weight of the rock and what it’s made of. One of the things is human tissue. They’ve found Eagle 1.
The commander tells Alan to abort and Alan tells Kelly to come back. He doesn’t respond. Alan heads out after Kelly and finds him floating in space. Kelly is taken back to the Eagle, then to medical. His brain readings are strange, given he’s full anesthetised. Kelly’s wife arrives and, after she’s taken back to her quarters, they notice that the monitor displaying Kelly’s brain patterns is displaying computer data now. David is contacted; he says that the computer is transmitting data to Kelly’s brain, then through him to the point where the Eagle was crushed and Kelly was affected. Then the strange glyphs appear again and David says the process has reversed. Koenig is concerned that computer may be being reprogrammed.
Kelly comes around despite efforts to keep him under. The commander lets him leave medical to see where he’s going. Which is the computer room. Dr Mathias contacts the commander, who says to contact David and wait until Koenig gets there. David arrives shortly after the commander; Kelly is reprogramming the computer so fast he can’t keep up with the details. Kelly proves very difficult to stop, until computer is turned off. Which seems to cause him physical pain.
The Moon is heading to the same place where Eagle 1 was crushed. This will not be good for Alpha nor, quite possibly, for the entity that’s there. Neither seems able to avoid the other.