When Commander Prescott exits a building, he passes a sign that reads, "Flight Operations - Authorised Personnel Only". The film is set on an American Air Force base in New Mexico, and no sign in the United States would use the British spelling of "authorized", with an "s" instead of a "z". (The fact that the film was shot in England accounts for this error.)
At 19 minutes into the movie Dan Prescott is looking out the window at a rocket that's just lifted off. The rocket is at least hundreds if not thousands of feet in altitude when Prescott says 'look at that thing go'. However, Prescott is looking down out of the window when the rocket would clearly have been high in the sky. In fact the window blinds in the window are positioned in such a way that Prescott wouldn't have been able to see the rocket in the air, anyway.
In addition to the already-mentioned goof regarding one sign using the British spelling of "Authorised" instead of the American spelling (with a z instead of an s) that would be seen in New Mexico, Commander Prescott twice enters yet another building (the University of Albuquerque Aviation Medicine Dept.) with a sign reading "Scientific Station Authorised Personnel Only".
Though set in New Mexico, the film (except for some stock and establishment shots) was shot entirely in England, which is why scenes purportedly taking place in an arid state in the American southwest desert feature heavily forested areas with trees, hedges and shrubbery unknown in New Mexico, cold ground fog, and English-style houses and country roads.
At the ransacked Blood Bank, the murdered Nurse (Sheree Winton) body has its nurse hat on when Capt. Ben Richards (Robert Ayres) is looking at her. When Cmdr. Charles Prescott (Marshall Thompson) goes to check her the hat is gone.