The Production Guide
Writer's Guide

10 THE STORY

Now, having described to some extent the Moon Base Alpha lifestyle, we must immediately state that all of that is true, only for a limited time. Because, in the very first show of the series, the Moon will suffer a massive atomic explosion in an unhappily man made accident. As a result, a chunk of the Moon will be ripped off and flung into space, causing the Moon itself to go careening out of orbit and headlong into the void, with the Moon Base upon it. Communication with Earth will be broken and the Moon Base will be left upon its own to survive, to seek a friendly planet to colonise, and to defend itself against other space-lives, for now they are invading aliens.

We can postulate, by the way, that the very nature of the horrendous accident allows the Moon Base people to survive somewhat because the crater exposed by the Moon chunk being ripped off becomes a source of raw material, necessary to be fashioned into essentials for Moon Base living.

The "chunk of the Moon" being ripped off is not seen in the series.