ITC had initially planned a 13-episode third season of the show (solely for the purpose of increasing the show's syndication package from 48 to 61 episodes, with some reports indicating it to have been running concurrently with a spin-off starring Catherine Schell as Maya). Unfortunately, not enough stations had placed renewal orders for the following season. It was rumored that had the show continued into a third season, Tony Anholt would've passed it up (after this episode finished filming, Anholt hired a new agent and went back to theater work where casting agents could see him in roles other than Tony Verdeschi). In a 1986 Starlog interview, Martin Landau expressed his belief that the real reason the show's third season failed to materialize was due to head of ITC Lew Grade's interest in branching out into motion pictures, which absorbed most of his finances. Schell confirmed this, stating that their third season was sacrificed to provide advertising budgets to support three different ITC films to prevent them from failing at the box office (The Cassandra Crossing (1976), March or Die (1977), Circle of Iron (1978)); the three films failed anyway at this series' expense. The only TV series Grade had funded after this show's second season (besides The Muppet Show (1976)) was Return of the Saint (1978), which only lasted one season due to its budget also being diverted toward Grade's film projects. Grade lost control of ITC in 1982; apparently, his film Raise the Titanic (1980) ended up sinking him.
This episode was made on a shoestring budget, as Season Two's funds had by now been depleted (one of the results being John Hug deleted from the cast, another being the lack of ceilings on the sets of the alien vessel, as well as none of the Alpha sections experiencing explosive decompression during the bombardment as previously demonstrated on War Games (1975)). All involved were aware this was the last episode, but at the time, the series finales didn't give any closure (possibly they were grasping at straws, hoping the series would be reinstated in the near future). Gerry Anderson and Fred Freiberger immediately started brainstorming ideas for a brand-new series, but nothing came to fruition. Anderson soon found himself flat broke, and experienced one failed project after another, including two films for the big screen; a thriller titled "Operation Shockwave" and a major space adventure called "Five Star Five"; both projects' financial support collapsed in 1978 and 1979, respectively, after months of pre-production (the latter causing many of his long-time associates to turn on him, as they had wound up unpaid for their work).
Johnny Byrne was appointed script consultant for Season Two of this series, and also contracted to write three scripts for this season. The three (written with the Season One format) consisted of "The Biological Soul" (which became The Metamorph (1976)), "The Face of Eden" (which became The Immunity Syndrome (1977)), and "Children of the Gods" (which Gerry Anderson regarded as the best thing he ever read). The Exiles (1976) by Donald James was penned around the same time. However, ITC intervened, filling the script editor role with American Fred Freiberger. When Freiberger came in as Season Two's producer and script editor in December 1975, he rewrote two of Byrne's scripts in his own style and to conform to Season Two's format ("The Face of Eden" only faintly resembling Byrne's script). Still, he wanted nothing to do with "Children of the Gods". Needless to say, Byrne had no love for this season or for Freiberger, but he had to honor the contract. So, he wrote this episode (in his opinion) very cartoonish to please Freiberger (as well as to mock him, knowing he'd love the script - it is an entertaining episode, but far below the intellect of Byrne's usual works). This series had been previously announced as cancelled as soon as this episode was completed. Freiberger's next project as a producer was for the fifth season of The Six Million Dollar Man (1974). That series was announced as canceled as soon as that season had come to a close, earning Freiberger a lousy reputation in the sci-fi community (earning the moniker "The Show Killer"), resulting from producing one season each of Star Trek (1966), Space: 1999 (1975), and "The Six Million Dollar Man", which all had wound up canceled after being in his hands. However, various people in the industry came to his defense (at least in the cases of "Star Trek" and "The Six Million Dollar Man"), claiming other factors were at work which caused those series' demise.
Original title: "The Return of the Dorcons", filmed 7 to 23 December 1976. This was the final shooting of the series until the fan-made Message from Moonbase Alpha (1999) (written by Johnny Byrne) was shown at the 1999 convention, featuring Zienia Merton as Sandra.
After plans for a third season of the show had been canceled, a letter-writing campaign was formed under the title "Save Space: 1999 Alliance" to try and bring the show back, but ITC failed to respond.