[1] The programme was notable for its combination of realistic spaceflight procedures, ensured by hiring BBC technical adviser James Burke, and its strong character-based writing.[11] Former actor Barry Letts had changed career into television direction in 1967 and had worked on series such as Z-Cars and The Newcomers before being asked to take over as producer of Doctor Who in 1970, where he first met Dicks.[16] The series was formally commissioned in December 1972 and would be made, as a co-production between the BBC and 20th Century Fox and the ABC network in America, during the break in production between Seasons 10 and 11 of Doctor Who.[17] The final two scripts, "The Dark Side of the Moon" and "The Gentle Rain" (later renamed "Castor and Pollux" and "Achilles Heel" respectively), were commissioned from John Lucarotti, a prolific writer whose credits included The Avengers, Doctor Who and The Troubleshooters.[20] Cast as David Caulder was Donald Houston, an experienced character actor, who had appeared in 633 Squadron and The Longest Day, and was known for playing authority figures.[citation needed] Ralph Bates, who was cast as Michel Lebrun, had first made a name for himself playing the Emperor Caligula in the Granada Television series The Caesars but was best known as a regular actor in the Hammer horror stable.[20] Recalling his guest appearance on Moonbase 3, in the episode "Behemoth", Peter Miles told TV Zone in 1991 that he was "asked to be like a gazelle and leap as I came down the hillock in full astronaut gear.[27] Filming continued at Ealing until 30 May 1973[2] before production moved to BBC Television Centre for the remaining scenes, mostly those set inside the moonbase, which would be recorded on videotape beginning on 18 June 1973.[2] Terrance Dicks has felt that Moonbase 3 was ultimately a failure: "The trouble was we built a too restrictive format for ourselves"[31] and that the series "lacked a sense of wonder and outrageousness".[32] Academic Peter Wright has said about Moonbase 3 that its "appeal to realism resulted in a disquieting sense of claustrophobia and isolation that undermined the optimism of its premise and captured the general mood of insularity felt (and often desired) in Britain in the early 1970s".