The communication console and screen from Klaatu's saucer featured in The Day the Earth Stood Still (1951) can be seen directly in the background of Labcentral's "Astro Physics" Laboratory where Vera Hunter and Dr. Hubbell Eliot have their confrontation. A map of the world has been placed behind the glass.
"M47" (Dr. Leslie Gaskell's designation in the movie for the so-called "asteroid") is in real life, one of the "missing" Messier Objects whose correct position was not definitively identified until 1959 (two years after the release of 'Kronos'). It is an open star cluster in the constellation of Puppis.
After a string of highly successful big budget science fiction films throughout the 1960s, Twentieth Century Fox considered remaking this film in the early 1970s in response to the energy crisis. The project was not green lighted and, by the end of that decade, accepted an offer from Wade Williams to buy the film and all rights. This film is now part of the "Wade Williams Collection."
'Spyros Skouros', then president of 20th Century Fox, liked the concept and reportedly urged the production of this film.
The long shots of Kronos moving were accomplished by animation, presumably the work of animator Gene Warren.
Before production began, the budget was cut. This required a second draft of the script which eliminated some character development and some expensive special effects sequences.
Baxter Ward, who played a TV news anchorman, was a real life TV news reporter at the timea.
Although he was fourth billed, George O'Hanlon, who played Arnie, was the most familiar face in the cast. For more than a decade, he was the star of the popular long running series of "Joe McDoakes" (aka "Behind the Eight Ball") comedy shorts which ended production the previous year.
Film writer Glenn Erickson has identified scenes of Mexican citizens running away from the robot that were scenes originally photographed in Hawaii for the 1956 release The Revolt of Mamie Stover (1956).
Inspired the giant robot in The Incredibles (2004).