The total of Jupiter's known moons presently stands at 79. Number 13 was discovered in 1974 and named Leda, which presumably means that this film is set in the mid-1970s; although no Atlantean civilisation relocated from Earth was noticed by its discoverers and no manned spaceflight there has yet been attempted (possibly because it is only 6 miles across).
After emerging from the V2 in which they made their three-week trip from Earth, the crew wander about deepest Hertfordshire for a bit before returning to what appear to be standing sets from previous historical productions at Elstree Studios at Borehamwood. The memorable use of excerpts from Borodin's 'Prince Igor' (acknowledged in the credits) pre-dates the use of Strauss in '2001'; but 'Fire Maidens from Outer Space' also shares with Kubrick's film the presence of Maya Koumani. (Prominently featured in the opening credits and as one of the dancing Fire Maidens, Ms Koumani later gets some dialogue, whereupon she is identified by name as what sounds like 'Nyssa'. In '2001' she appears as Dr Stretyeneva, one of the Russian delegation that meets Dr.Floyd at Space Station V.)
Interestingly enough, although there isn't the usual woman among the five-man crew (which includes the reassuringly familiar faces of Paul Carpenter, Sydney Tafler & Harry Fowler) - presumably because there'll be plenty of them were they're going - two of the six senior staff shown gathered round the radio at Mission Control are women.