NASA's planetary exploration program takes over where the Apollo moon missions left off, sending probes across the solar system through the 1970s. The film moves planet by planet: Mercury's cratered, airless surface; Venus's thick toxic atmosphere and surface heat; Mars's rugged terrain and the asteroid belt beyond it. Saturn gets extended treatment, its rings resolved into countless particles of ice and rock, with a look at its moons including Enceladus and the possibility of a subsurface ocean there. Uranus appears tilted on its side with the odd seasons that produces, and Neptune shows the fastest winds recorded in the solar system driving its surface storms. The film closes on the Voyager probes, launched in 1977, tracking their path out past the giant planets and into interstellar space, where they still carry the Golden Record's sounds and images of Earth. Directed by Colin Cantwell for Graphic Films Corporation, the film relies on animation and probe imagery rather than interviews to lay out what each mission found.