Continuity mistake: When John is trapped in the electrical anomaly he tries to answer the radio and it is shown exploding. When Don and Judy start rescuing John you can notice the radio is still there, one shot with the antenna up and one without, and another with no radio.
Lost in Space (1965)
1 continuity mistake in Island in the Sky
Starring: Guy Williams, June Lockhart, Mark Goddard, Marta Kristen
Other mistake: In one of the opening scenes with Will and Dr Smith, the Robot's power pack is clearly missing.
Robot: My micromechanism thanks you, my computer tapes thank you, and I thank you.
The Great Vegetable Rebellion - S3-E23
Trivia: Due to their uncontrollable laughter during filming of the infamous "Vegetable Rebellion" episode, Guy Williams and June Lockhart were written out of the next two episodes.