"Crater 101" is one of several "Captain Scarlet" scripts by Tony Barwick to include a mention of 10 July (the inscription on Nolan's charm states that the CB29 probe reached Neptune on 10 July 2058). Barwick liked to insert references to this date as it was his birthday. The script indicated that Lunarville 6 is smaller than Lunarville 7, which was destroyed in the episode of the same name. However, the two colonies are introduced with the same establishing shot, which was duplicated from the earlier episode for its appearance in "Crater 101".