Characters played by Richard Eyer
Timmie Merrinoe
Characters played by Philip Abbott
Dr. Tom Merrinoe
Characters played by Diane Brewster
Mary Merrinoe
Characters played by Harold J. Stone
Gen. Swayne
Characters played by Robert H. Harris
Prof. Frank Allerton
Characters played by Dennis McCarthy
Col. Macklin
Characters played by Alexander Lockwood
Arthur Kelvaney
Characters played by John O'Malley
Prof. Baine
Characters played by Robby the Robot
Robby
Characters played by Gage Clarke
Dr. Bannerman
Characters played by Than Wyenn
Prof. Zeller
Characters played by Jefferson Searles
Prof. Foster (as Jefferson Dudley Searles)
Characters played by Alfred Linder
Martin Computer
Characters played by Ralph Votrian
1st Gate Sergeant
Characters played by Michael Miller
2nd Gate Sergeant
Characters played by Rayford Barnes
Capt. McLaren (uncredited)
Characters played by Helen Kleeb
Miss Vandergrift (uncredited)
Characters played by Marvin Miller
Robby the Robot (uncredited)
Characters played by Alvy Moore
Scientist #4 (pranks scene) (uncredited)
Characters played by Gary Vinson
Young soldier (uncredited)