Michael Caine

Character: Brad Crane

Katharine Ross

Character: Capt. Helena Anderson

Richard Widmark

Character: Gen. Thaddeus Slater

Richard Chamberlain

Character: Dr. Hubbard

Olivia de Havilland

Character: Maureen Schuester

Ben Johnson

Character: Felix

Lee Grant

Character: Anne MacGregor

José Ferrer

Character: Dr. Andrews

Patty Duke

Character: Rita

Slim Pickens

Character: Jud Hawkins

Bradford Dillman

Character: Maj. Baker

Fred MacMurray

Character: Maj. Clarance Tuttle

Henry Fonda

Character: Dr. Walter Krim

Cameron Mitchell

Character: Gen. Thompson

Christian Juttner

Character: Paul Durant

Morgan Paull

Character: Dr. Newman

Alejandro Rey

Character: Dr. Martinez

Don 'Red' Barry

Character: Pete Harris

Elizabeth Rogers

Character: Woman Scientist

Doria Cook-Nelson

Character: Mrs. Durant

Robert Varney

Character: Mr. Durant

Ernie F. Orsatti

Character: Duty Officer

Patrick Culliton

Character: Sheriff Morrison

John Furlong

Character: Cameraman

Chris Petersen

Character: Hal

Jerry Toomey

Character: Eddie

Barbara Costello

Character: Receptionist / Nurse

Jenifer Taurins

Character: Nurse

David Himes

Character: Radioman

Mara Cook

Character: Secretary

Joey Eisnach

Character: Bee Boy

Stephen Powers

Character: Radarman

Chris Capen

Character: Lieutenant

Tony Haig

Character: Officer #2

Bill Snider

Character: Radarman #2

George Simmons

Character: Nurse

Arell Blanton

Character: Sergeant

Trent Dolan

Character: Radio Sergeant

John Williams

Character: Launching Officer

Steven Marlo

Character: Pilot #1

Phil Montgomery

Character: Mechanic

Jim Galante

Character: Doctor

Frank Blair

Character: Self

Marcia Nicholson

Character: Captain

Arthur Space

Character: Engineer

Chuck Hayward

Character: Standby Engineer

Glenn Charles Lewis

Character: Chemical Warfare Guard

Art Balinger

Character: Radio Announcer

Michael Sheehan

Character: Airman #1

Howard Culver

Character: Airman #2

Buzz Barbee

Character: Briefing Guest (uncredited)

Ken Clayton

Character: Dr. Moore (uncredited)

Marneen Fields

Character: Train Passenger (uncredited)

Bob Harks

Character: Townsman (uncredited)

Mike Johnson

Character: Burning Man (uncredited)

Jack Krupnick

Character: Train Passenger (uncredited)

Lawrence Moran

Character: Colonel's Son (uncredited)

Monty O'Grady

Character: Briefing Guest (uncredited)

John Otrin

Character: Wild Lines (uncredited)

Leoda Richards

Character: Briefing Guest (uncredited)

Norman Stevans

Character: Briefing Guest (uncredited)