In the first season episode “Magic Mirror” Judy is seen to be dictating a letter to her “dear cousin Joan.” We are not told through whom she is related to Joan, but the Alpha Control Reference Manual identifies Joan as the daughter of Maureen’s elder sister. On numerous occasions over the course of the series Dr. Smith boasts of his forebears to impress either the Robinsons or an alien. On one occasion (“The Astral Traveller”) this attempt at boasting of his family connexions backfires when it turns out that his ancestors were the mortal enemies of the ghost Hamish.