On screen
Cast
23 credited performers
Joseph Cotten
Admiral
Lloyd Haynes
Lt. Dave Burston
Dewey Martin
Skip Langley
Leonard Nimoy
Comdr. Phil Kettenring
William Windom
Capt. Frank Reardon
Keenan Wynn
Orville Kelly
Malachi Throne
Dr. Dykers
Sam Elliott
Ens. William 'Bill' Sandover
Ivor Barry
Donald Ellington
Ron Masak
CPO Corky Schmidt
Artwork unavailable
Gordon Hoban
Second Karp (False Karp)
Artwork unavailable
Lee Stanley
Lt. Manners
Artwork unavailable
David Thorpe
Lt. Benson
Artwork unavailable
Henry Olek
Cab Driver
Artwork unavailable
Dale Tarter
Clarence W. "CW" Karp (First Karp)
Artwork unavailable
James Beach
Radar Operator
John Winston
English Scientist
Larry McCormick
Radio Operator
Artwork unavailable
Paul Sears
Paine
Artwork unavailable
Ellen Tucker
Mrs. Karp
Artwork unavailable
Bill Keller
Shore Patrolman
Bobby Herbeck
Sonarman
Artwork unavailable
Bo Johnson
Seaman