This pilot was never aired during the initial broadcast run or in syndication (presumably because Dr. Smith and the Robot were not included in the original cast). It was considered to be lost until it was discovered in the mid -'90s. The Sci-fi Channel had a special called "Pilot Playhouse" where it aired the first episodes of various science-fiction TV shows. It was during research for this special that the original pilot was located and broadcast for the very first time.
In the unaired pilot, the Robinson ship is called Gemini 12. This was changed to Jupiter 2 for the rest of the series.
The special effects were filmed in color, even though the show was in black-and-white so that the footage could be reused if the show ever switched to color.
Shortly after the series premiere, the Twentieth Century-Fox Special Effects shop was contacted by NASA training facilities in Houston, TX. concerning the special-effect rigging used to simulate a space walk. A team of technicians from NASA traveled to the studio lot and spent a few days with the Special Effects crew who were involved with the music-wire flying rigging. NASA had considered possibly using the same rigging for training future astronauts in space-walking applications, but finally decided to use the underwater-training technique instead.
The only appearance of an alien ostrich who liked to get out of its pen and run away from young Will Robinson.