When the Jupiter 2 flies out of the alien hangar bay, the exterior shot shows four individuals on the bridge, standing widely apart. However, in the next interior shot, there are five people, standing closely together.
Before becoming lost, the Jupiter 2 would have reached Alpha Centauri, a distance of approximately 4 light years, in about 5 years. However, the spaceship was written off by Alpha Control and declared beyond the limits of the Milky Way, but the closest edge of our galaxy is 25,000 light years showing this to be impossible.
Dr. Smith states he has won three GM (Grandmaster) titles at the Oxford University Chess Society. In fact this goes against the actual rules of the world chess organization FIDE (World Chess Federation) that state a chess title is won for life.
In this episode, the first of the regular series, it's heard that the Robinson's voyage has taken five years so far. This differs from the 98 years that had been stated in the unaired original pilot.
Dr. Smith holds the rank of Colonel.
The space ship that the Robinsons are launched in is called the Gemini XII, as an extension of the old Gemini space program. This will be changed to the Jupiter II in the regular series.
Maureen and John Robinson have a rare on-screen kiss.
The Gemini XII uses liquid oxygen or LOX, one of the physical forms of elemental oxygen, which is used by NASA to this day.
The song Will plays on the guitar is Greensleeves.
In this unaired pilot, the ship crashes as the result of a meteor shower, rather than from sabotage as in the second pilot/first episode.
Continuity Goof: The original trip of the Gemini XII was to take 98 years. The Robinsons left Earth on October 16, 1997, and landed on the unnamed planet in June 2001. Most of the story takes place in December 2001, six months after they crash land.