Lost in Space Harris as an older Will Robinson and Zachary Smith. They attempt one more time to return to Earth but find that they are "Lost in Space ... Forever!" Lost in Space showcased a variety of transportation methods of transportation in the series. The "Jupiter 2" is a two-deck, nuclear powered flying saucer spacecraft. The version seen in the series was depicted with a lower level and landing legs. On the lower level were the atomic motors, which use a fictional substance called "deutronium" for fuel. The ship's living quarters feature Murphy beds, a galley, a laboratory, and the robot's "magnetic
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.