The original Lost In Space was created by Irwin Allen who also created a show called The Time Tunnel. This episode has a scene where John Robinson descends a shaft into a planet. In the first shot down the shaft it looks exactly like the Time Tunnel.
It seemed to have an ET sort of theme to it as the Jupiter 2 was covered over with protective sheeting like Elliot's house was. Will went to see if the robot was OK like Elliot did for ET. It also had a similar music theme like ET's theme tune too.