 In an interview with Starlog magazine in the late 1970s, Douglas  Trumbull revealed that the plot of the movie in the original version  of the script was quite a bit different from what was actually  filmed. In this version, the Space Freighters were on permanent duty  carrying biological domes. When theyre finally told to blow the  domes and return to earth, it is because the freighters are going to  be scrapped. The Freeman Lowell character in this version was an  older, more curmudgeonly man who simply doesnt want to return to  earth and forced into retirement, so he steals the Valley Forge,  "Shoots the rapids" through Saturns Rings to make it look like his  ship is destroyed, and heads off into deep space. As in the filmed  version, he reprograms the robots for some companionship, and the  subplot involving the plants dying due to a lack of light were  involved, but his main interest in the plants was simply as a means  of extending his limited food supplies on the ship. In the second  half of the film, he receives a signal which he realizes is from an  alien ship passing through the solar system, and decides to approach  it 