This is the pilot episode of Lost in Space. After changes were made, the series would begin anew with "The Reluctant Stowaway." Footage from the pilot was later used in the first 5 episodes, combined with new footage. While elements of the story were retained, the original pilot is different from the series in many ways, notably the lack of the Dr. Smith and The Robot characters. It is for this reason not generally accepted as canon, due to these extreme differences.