Paul Hubschmid as Prof. Nesbitt

Paula Raymond as Lee Hunter

Cecil Kellaway as Prof. Elson

Kenneth Tobey as Col. Evans

Donald Woods as Capt. Jackson

Lee Van Cleef as Corp. Stone

Steve Brodie as Sgt. Loomis

Ross Elliott as George Ritchie

Jack Pennick as Jacob Bowman

Ray Hyke as Sgt. Willistead

Paula Hill as Miss Ryan

Michael Fox as ER Doctor

Alvin Greenman as Radar Man #1

Frank Ferguson as Dr. Morton

King Donovan as Dr. Ingersoll