Originally commissioned to create a child-friendly introduction to Albert Einstein's special relativity theory in the form of an exciting action-adventure, Anderson and Byrne conceived The Day After Tomorrow as a television pilot for a potential series and gave it an alternative episode title of "Into Infinity". Ultimately, Anderson's limited budget prevented additional episodes from being made.
NBC aired this obscure genre pilot in prime time as a so-called "Special Treat" in November of 1975, even as Year One of the Gerry and Sylvia Anderson TV series Space:1999 (1975-1977) was being broadcast in syndication around the country.
In the spring of 1975, after filming on "Year One" of Space: 1999 had been completed, NBC agent George Heinemann contacted Group Three producer Gerry Anderson with an idea for a new science-fiction TV series. This would comprise seven one-hour episodes designed to teach children about scientific subjects in the format of an entertaining action-adventure. To publicise the series, NBC undertook to distribute information leaflets to schools. Heinemann hired Anderson to produce a TV special that would discuss, as its main topic, the physicist Albert Einstein's theory of special relativity, which holds that the speed of light cannot be exceeded and remains constant whether an object is still or in motion.
In preparation for his work on the special, Gerry Anderson researched Einstein's achievements; in his authorised biography, he admitted that he did not understand any of the physicist's theories.
Most of the cast of The Day After Tomorrow had appeared in or otherwise contributed to earlier Anderson productions.