Timmie Merrinoe
Dr. Tom Merrinoe
Mary Merrinoe
Gen. Swayne
Prof. Frank Allerton
Col. Macklin
Arthur Kelvaney
Prof. Baine
Dr. Bannerman
Prof. Zeller
Prof. Foster
Martin / Computer
1st Gate Sergeant
2nd Gate Sergeant
Capt. McLaren (uncredited)
Miss Vandergrift (uncredited)
Scientist (uncredited)
Young soldier (uncredited)
Robby the Robot (voice) (uncredited)