In Britain, the second season was broadcast over the course of two years, with part shown in the autumn/winter of 1976-77, then a season break until August 1977, with new episodes running into the autumn. The first ITV region to finish the series was LWT (London) which broadcast the final episode ("The Dorcons") in November 1977. Some ITV regions did not conclude the series until 1978, and one region (HTV Wales) did not show the final episodes until 1984.
Barry Morse decided to leave the series after Season 1 had ended. An explanation of his absence was written into the first episode of Season 2, "The Metamorph", but never made it to the finished episode. Dialog was to indicate he had been in a faulty spacesuit.
Moonbase Alpha's final fate was revealed in a short fan-made film shown at the 1999 convention, where original cast member Zienia Merton reprised her role as Sandra Benes and described the final abandonment of Moonbase Alpha for their new home on an unnamed planet.
The trivia item below may give away important plot points.
The number of days since the original explosion ranges wildly between 300 and 3000+ in Helena's opening logs throughout the series. If we use Maya's joining the crew as a marker, Helena has said that their journey is in to the thousands of days before we ever meet Maya. However, after Maya's arrival, her logs continue to bounce from anywhere between 300 and 3000+ days.