Trivia: Originally the film was going to end with the Starchild activating the nuclear launch platforms orbiting Earth, using the planet's destruction as a means to accelerate the evolution of mankind into it's new universally intelligent form. Stanley Kubrick eventually decided against this as it was too similar to the ending of his previous film "Dr. Strangelove".
Trivia: To film Dave Bowman's explosive transition from the pod into the Discovery, a vertical airlock set was constructed. Keir Dullea was suspended on wires and pulled to the top of the set as the camera shot upwards from below. This, combined with the establishing shot of the pod lined up with the airlock door, gave the illusion that he was floating horizontally into the ship - the wires suspending him from the ceiling were hidden behind his body.
Trivia: Much has been written about the scene where Bowman enters the air lock without his helmet. Studies done by NASA have shown that humans can survive in vacuum for brief periods if they do not hold their breath. Some have commented that Dave appears to hold his breath before blowing the hatch, but careful study of the scene does not show this, as it seems he is simply grimacing, bracing himself for the coming effort. When the film was first shown in theaters, many of them handed out souvenir booklets which included references to this study.