Ring Around the Moon. Season 1, Episode 19. First broadcast Thursday 15 January 1976.

This month, the people of the mythical planet Triton are so (understandably) keen to avoid any contact with the human race that they send a large yellow lightbulb to capture the Moon and issue urgent demands for the entire contents of the base’s OneDrive. These demands mostly involve abducting Helena and inserting things into her brain, giving Barbara the chance to try out a bewildering array of new facial expressions.

The Infernal Machine. Season 1, Episode 18. First broadcast Thursday 8 January 1976.

This month, Leo McKern turns up on the Moon with his enormous scary spaceship husband, who threatens to kill everyone on the base and decimate its sizeable collection of Kenner die-cast model vehicles. But there’s also a moving depiction of grief here, and some kind of attempt to explore why exactly we all continue putting up with each other.

The Last Sunset. Season 1, Episode 17. First broadcast Thursday 1 January 1976.

This month’s mysterious immortal beings are — as usual — keen to avoid meeting the crew of Moonbase Alpha, but instead of simply killing everyone on the base, they decide to give them everything they ever wanted. Inevitably, things turn out very badly.

Another Time, Another Place. Season 1, Episode 16. First broadcast Thursday 18 December 1975.

This month, an unexpected scripting anomaly returns the Moon to Earth’s orbit, where it will inevitably crash into another slightly older Moon, killing everyone on the base. But in the meantime, we experience a strange and elegiac meditation on having nowhere to belong and on our subjection to the vagaries of time. Haunting and inexplicable.

The Full Circle. Season 1, Episode 15. First broadcast Thursday 11 December 1975.

This month, a picnic on a verdant new planet — fresh air, space buggies, aggressive and bloodthirsty lice, hitting people with rocks, and menacing people with burning knives. But, for once, no one wants to kill everyone on the base, except the audience, probably.

Earthbound. Season 1, Episode 14. First broadcast Thursday 4 December 1975.

This month, to our surprise, Christopher Lee turns up on Alpha, not to kill everyone on the base for once, but just to be terribly nice to everyone. But Alpha harbours a villain of its own, one even deadlier than Christopher Lee, but mostly to himself.

Matter of Life and Death. Season 1, Episode 13. First broadcast Thursday 27 November 1975.

In this month’s long-delayed first regular episode, Barbara’s zombie husband returns from the dead to warn Koenig about Alpha’s planned Operation Exodus — a plan which will (inevitably) kill everyone on the base. But does he listen?

End of Eternity. Season 1, Episode 12. First broadcast Thursday 20 November 1975.

This month, Peter Bowles drops Jonty and Charlotte off at school before heading over to Pinewood Studios to spend the day throwing security guards at each other and threatening to torture and kill everyone on the base. While wearing a surprisingly lovely outfit.

Guardian of Piri. Season 1, Episode 11. First broadcast Thursday 13 November 1975.

Just six weeks ago, famous miserable bastard John Koening was saving the entire crew from the horrific prospect of eternal bliss in the company of the hottest models the 1970s could offer. This week, he’s doing the same thing, only this time he’s brought a gun.

Black Sun. Season 1, Episode 10. First broadcast Thursday 6 November 1975.

This month’s eerie and irrational space anomaly is, of course, intent on killing everyone on the base, and so with no hope left, the crew have no choice but to discover love, tranquility and grace. And to learn the valuable lesson that certain death is never certain when everyone is still contracted to do another twenty episodes.