David Freeman
Max (voice) (as Paul Mall)
Bill Freeman
Helen Freeman
Carolyn McAdams
Jeff (8 years)
Jeff (16 years)
Dr. Louis Faraday
Troy
Dr. Carr
Mrs. Howard
Mr. Howard
Detective Banks
Woman Officer
Night Guard Brayton
Technician #1
Technician #2
Technician #3
Scientist #1
Scientist #2
Observation Guard
NASA Officer
Hangar Guard #1
Hangar Guard #2
Control Room Guard #1
Control Room Guard #2
Radar Technician #1
Radar Technician #2
Lieutenant King
Agent #1
Agent #2
Gas Station Attendant
Tourist Man
Tourist Child
Jennifer Bradley
Newscaster #1
Newscaster #2
Kid in Mustang
Bixby (as Bruce Lake)
NASA Technician #1
NASA Technician #2 (as Fritz Brauner)
Puppeteer
Puppeteer (voice)
R.A.L.F. (voice) (uncredited)