Michael Caine

Brad Crane

Katharine Ross

Capt. Helena Anderson

Richard Widmark

Gen. Thaddeus Slater

Richard Chamberlain

Dr. Hubbard

Olivia de Havilland

Maureen Schuester

Ben Johnson

Felix

Lee Grant

Anne MacGregor

José Ferrer

Dr. Andrews

Patty Duke

Rita

Slim Pickens

Jud Hawkins

Bradford Dillman

Maj. Baker

Fred MacMurray

Maj. Clarance Tuttle

Henry Fonda

Dr. Walter Krim

Cameron Mitchell

Gen. Thompson

Christian Juttner

Paul Durant

Morgan Paull

Dr. Newman

Alejandro Rey

Dr. Martinez

Don 'Red' Barry

Pete Harris

Elizabeth Rogers

Woman Scientist

Doria Cook-Nelson

Mrs. Durant

Robert Varney

Mr. Durant

Ernie F. Orsatti

Duty Officer

Patrick Culliton

Sheriff Morrison

John Furlong

Cameraman

Chris Petersen

Hal

Jerry Toomey

Eddie

Barbara Costello

Receptionist / Nurse

Jenifer Taurins

Nurse

David Himes

Radioman

Mara Cook

Secretary

Joey Eisnach

Bee Boy

Stephen Powers

Radarman

Chris Capen

Lieutenant

Tony Haig

Officer #2

Bill Snider

Radarman #2

George Simmons

Nurse

Arell Blanton

Sergeant

Trent Dolan

Radio Sergeant

John Williams

Launching Officer

Steven Marlo

Pilot #1

Phil Montgomery

Mechanic

Jim Galante

Doctor

Frank Blair

Self

Marcia Nicholson

Captain

Arthur Space

Engineer

Chuck Hayward

Standby Engineer

Glenn Charles Lewis

Chemical Warfare Guard

Art Balinger

Radio Announcer

Michael Sheehan

Airman #1

Howard Culver

Airman #2

Buzz Barbee

Briefing Guest (uncredited)

Ken Clayton

Dr. Moore (uncredited)

Marneen Fields

Train Passenger (uncredited)

Bob Harks

Townsman (uncredited)

Mike Johnson

Burning Man (uncredited)

Jack Krupnick

Train Passenger (uncredited)

Lawrence Moran

Colonel's Son (uncredited)

Monty O'Grady

Briefing Guest (uncredited)

John Otrin

Wild Lines (uncredited)

Leoda Richards

Briefing Guest (uncredited)

Norman Stevans

Briefing Guest (uncredited)