Often wrongly described as a remake of Genesis II (1973), Planet Earth is in fact a second and upgraded pilot film for the proposed series developed by Star Trek (1966-1969) creator Gene Roddenberry. It continues the story of 20th century scientist Dylan Hunt in the distant, post-apocalyptic future but there had been major changes in all areas – network CBS had passed on the first pilot, so copyright owners Warner Bros. Television took the idea off to ABC who seem to have thrown a bit more money at the second film, which was more action-packed and colourful and which also saw many cast changes – chiefly, Alex Cord was out as Hunt and in came the more charismatic John Saxon.

The second film doesn’t bother rehashing the back story – Hunt simply muses on his circumstances in his log (shades of Star Trek) at the start and then we’re off and running with a whole new story. Like Genesis II, the story is set in the year 2133 in the aftermath of a nuclear war. The Earth is healing itself and the people of Pax (either a country, a city or an organisation, it’s never clear) from are trying to restore civilization to the primitive tribes through science and technology. Dylan Hunt (John Saxon), the NASA scientist from 1979 who was cryogenically frozen and woke up in the 22nd century, leads a mission that is attacked by the primitive mutants known as the Kreeg, during which Pater Kimbridge (Rai Tasco replacing Percy Rodrigues from the first film) is badly wounded. His only hope is a surgeon named Jonathan Connor (Jim Antonio) who went missing some time earlier. Hunt and his team, Baylok (Christopher Cary), Isiah (Ted Cassidy, back from Genesis II) and Harper-Smythe (Janet Margolin) set off in search of him but fall foul of the Confederacy of Ruth, a matriarchal society ruled over by Marg (Diana Muldaur).

Planet Earth, with its skin-tight uniforms and more plentiful technology has a more pronounced Star Trek feel to it and it gives perhaps a better idea of what the proposed series could have been. It’s a lot more fun than the rather dull Genesis II but it still wasn’t enough to persuade ABC that the series was worth pursuing. It’s a more exciting film than its predecessor, and Marc Daniels, a veteran of Star Trek, directs with a bit more oomph than John Llewellyn Moxey could muster in Genesis II. But it was all to no avail.

Much of the problem lies again at the door of Roddenberry and the script he cowrote with Juanita Bartlett, later a producer and key writer on the hugely popular The Rockford Files (1974-1980). For all the surface changes, this is essentially the same story as the first film – Hunt and his team infiltrate a repressive society and lead a revolution to overthrow its autocratic leader. Yes, the costumes have been spruced up and the leading man is more interesting (if rather like William Shatner’s Captain Kirk) but it’s the same old same old and there’s very little anyone can do to disguise that fact. It looks good – the “sub-shuttle” set from Genesis II is pressed into service again and the University of California buildings at Irvine makes for an attractive stand-in for the Pax headquarters.

Star Trek had been at its most irritating when it succumbed to proselytising and there’s a tendency for Planet Earth to do the same sort of thing. Roddenberry’s heart was always in the right place, but he could often be heavy handed and far too literal. We get a few too many moments of Saxon staring wonderingly at the reborn landscape around him, pontificating about how we got here. And for all his liberal credentials, Roddenberry wasn’t above having his Native American character Isiah referred to as a “savage” going unchallenged and featuring that hoariest of sexist science fiction standbys, the man-hungry Amazon tribe (“Women’s lib,” muses Hunt, “or women’s lib gone mad?”). In fairness, Roddenberry later claimed that this storyline – which feels a bit like we’re watching someone’s sexual fantasy – was forced on him by the network.

Star Trek had gone through two pilots – The Cage and Where No Man Has Gone Before – before it settled down into the series, we all know and love so Roddenberry must have thought that there was still hope that someone would pick up the Genesis II series. But no-one did – ABC decided that The Six Million Dollar Man (1974-1978) was a better bet. Warners and ABC dusted down the basic idea, without Roddenberry this time (he’d given up by now and gone back to Paramount to work on the equally doomed Star Trek: Phase II) as Strange New World (1975) which made even bigger changes to the story and proved to be interminably dull. Andromeda (2000-2005) finally saw Dylan Hunt return, this time in the shape of Kevin Sorbo, though it only kept the most basic of ideas before talking off in a direction more inspired by Star Wars (1977) than Genesis II.