Brad Crane
Capt. Helena Anderson
Gen. Slater
Dr. Hubbard
Maureen Schuester
Felix
Anne MacGregor
Dr. Andrews (as Jose Ferrer)
Rita (as Patty Duke Astin)
Jud Hawkins
Maj. Baker
Mayor Clarence Tuttle
Dr. Walter Krim
Gen. Thompson
Paul Durant
Dr. Newman
Dr. Tomas Martinez
Pete Harris
Woman Scientist (extended version only)
Mrs. Durant (as Doria Cook)
Mr. Durant
Duty Officer (as Ernie Orsatti)
Sheriff Morrison
Cameraman
Hal
Eddie
Receptionist / Nurse (extended version only)
Nurse (extended version only)
Radioman (extended version only)
Secretary
Bee Boy
Radarman
Lieutenant
Officer #2
Radarman #2
Nurse
Sergeant
Radio Sergeant
Launching Officer
Pilot #1 (as Steve Marlo)
Mechanic
Doctor (extended version only)
Self
Captain
Engineer
Standby Engineer
Chemical Warfare Guard
Radio Announcer
Airman #1
Airman #2
Military Officer (uncredited)
Briefing Guest (uncredited)
Controller (uncredited)
Dr. Moore (uncredited)
Technician (uncredited)
Train Passenger (uncredited)
Townsman (uncredited)
Burning Man (uncredited)
Colonel's Son (uncredited)
Wild Lines (uncredited)
Officer at Missile Complex (uncredited)