Irwin Allen's Lost in Space S02E27 - The Phantom Family

While John and Maureen are away observing volcanic activity, the alien scientist Lemnoc captures Don, Judy, Penny, and Dr. Smith and replaces them with android duplicates. Lemnoc then forces Will and the Robot to train the duplicates in survival skills, hoping that they will be an inspiration to his own people, who are losing the will to live.