Jupiter 1 is a spacecraft from Earth in the Lost in Space movie. It is used to launch the Jupiter 2 into space. Resembling the original spacecraft from the series, it was powered by large rockets on its underside. In the Innovation Comics, a ship also called the Jupiter One was seen, a precursor to the original spacecraft. It was also mentioned in the the Alpha Control Reference Manual, both instances ambiguously canon. It was depicted as being destroyed in each of these appearances.
One source states that The Jupiter 1 was originally used for a 'near deep space' survey mission and returned successfully to Earth. When it was decided to take the Jupiter program in a different direction the Jupiter 2 was constructed on entirely different lines. At this point the hull of the Jupiter 1 was gutted and refurbished to serve as an element in the launching procedure of the Jupiter 2.