Lost in Space are to be cryogenically frozen for the voyage, and they are set to be unfrozen when the spacecraft approaches its destination. Meanwhile, Dr. Zachary Smith (Jonathan Harris), Alpha Control's doctor, is revealed to be a saboteur on behalf of an unnamed nation. After disposing of a guard who catches him on board the spacecraft, Smith reprograms the "Jupiter 2"s B-9 environmental control robot (voiced by Dick Tufeld) to destroy critical systems on the spaceship eight hours after launch. Smith, however, becomes trapped aboard at launch and his extra weight throws the "Jupiter 2" off course, causing it to encounter a
Lost in Space job for its "Lost in Space" appearance, while space monster costumes would be reused on "Voyage" as sea monsters. The clear round plastic pen holder used as a control surface in the episode "The Derelict" turned up regularly throughout the show's entire run both as primary controls to activate alien machinery (or open doors or cages), and as background set dressing; some primary controls were seen used in episodes such as Season 1's "The Keeper (Parts 1 and 2)", "His Majesty Smith", and Season 3's "A Day At The Zoo", and "The Promised Planet". Spacecraft models, were also routinely re-used.