Click the arrow to watch the film. Video source: The Mars Underground YouTube channel.
Well, this never happened.
This week's Retro Saturday is a 23-minute 1968 film called Nuclear Propulsion in Space. Jointly produced by NASA and the Atomic Energy Commission, it foresaw the use of nuclear-powered upper stages on a Saturn V-like system to send crew to Mars.
As recounted by Los Alamos National Laboratory article, nuclear propulsion had proven quite promising in the 1960s.
But the technology would turn out to have no use.
By 1970, the Nixon administration, Congress and the American public had no taste for more extravagant human spaceflight programs. Nixon's Space Task Group proposed a Space Transportation System to service an Earth-orbiting permanently manned space station. A space tug, possibly propelled by nuclear engines, was an option.
The Space Task Group recommendations were largely ignored, although they did evolve into today's Space Shuttle. The "STS" moniker for a Shuttle mission stands for Space Transportation System.
The idea of an international space station (that wasn't its original name) came out of Nixon's desire to use the U.S. human spaceflight program as a diplomatic tool to reward friends and punish enemies.
The relatively low thrust provided by nuclear engines was of little use on the ground, and the space tug idea was dropped, so NASA shelved its ideas for nuclear propulsion.
The uncertainty about the future of NASA's human spaceflight program is clear in the narrator's final words about nuclear propulsion:
It will be available when this nation determines its next great objective in space.