WMG: Space: 1999

The explosion that hurled the Moon across space was magnetic, not atomic in nature

  • Perhaps it affected the quantum field and caused the Moon to slip between normal and hyperspace at random intervals.
    • In three episodes of the first season ("Black Sun", "Collision Course" and "The Testament of Arkadia") and possibly a fourth ("War Games"), it's either theorized or shown outright that a "cosmic intelligence" had a hand in the original lunar explosion and the Alphans' later travels.
    • Not much wild in that idea. David Hirsch of Starlog Magazine proposed the idea of a Mysterious Unknown Force having a part in the survival of Moonbase Alpha way back in 1980, and the idea has been taken up by many fans.
    • The Expanded Universe novels go on to elaborate further on the "cosmic intelligence" part of the plot. Most definitely, it has had a hand in keeping the Alphans alive for so long.

The whole "Moon knocked out of orbit" situation is just a very elaborate hoax