Two weeks were allotted for shooting the episodes (versus a 6 or 7 day shoot on Star Trek), so even without reshoots, overruns and the like, it would've taken 48 weeks just to shoot everything. Year One took even longer that that, though, because early on, Lee H. Katzin (who had been hired to be one of the main directors on the show) kept dragging his feet. He was very slow to get footage shot. The pilot took 23 days to shoot (almost twice as long as allotted) , and it was way overlong! They screened the pilot for ITC and everyone panicked. It was overlong and dull. Gerry Anderson had to go back, cut a bunch of stuff out (he had been a film editor at one time), then write new bridging sequences and take 3 more days to shoot new footage to make the episode come out at 50-ish minutes and still make sense. When the new version was shown, ITC basically said to Gerry, "you saved our bacon!" Anderson gave Katzin another chance (on "Black Sun"), but instead of the allotted two weeks, it took three-and-a-half weeks to shoot! After yet another overrun, they decided not to use him anymore. There was also a one-month break in June/July of 74, and a random week off here or there, but mostly, production kept to an episode every two weeks, for the most part.