Arthur Hill

Dr. Jeremy Stone

David Wayne

Dr. Charles Dutton

James Olson

Dr. Mark Hall

Kate Reid

Dr. Ruth Leavitt

Paula Kelly

Karen Anson

George Mitchell

Jackson

Ramon Bieri

Major Manchek

Peter Hobbs

General Sparks

Richard O'Brien

Grimes

Eric Christmas

Senator from Vermont

Peter Helm

Sgt. Crane (Piedmont team)

Carl Reindel

Lt. Comroe

Ken Swofford

Toby (technician)

Frances Reid

Clara Dutton

Richard Bull

Air Force Major

John Carter

MP Capt. Morton

Glenn Langan

Cabinet Secretary (uncredited)

Susan Brown

Allison Stone (uncredited)

Walter Brooke

Assistant to Cabinet Secretary (uncredited)

Jan Burrell

Mother - Piedmont (uncredited)

Michael Crichton

Bearded Surgeon (uncredited)

David McLean

Sen. McKenzie (uncredited)

Emory Parnell

Pete 'Old Doughboy' Arnold (uncredited)

Michael Pataki

Operator of 'The Hand' (uncredited)

Quinn K. Redeker

Capt. Morris (uncredited)

Garry Walberg

Technician (uncredited)

Ivor Barry

Murray (uncredited)

Lance Fuller

Man (uncredited)

Don Messick

Alarm (voice) (uncredited)

Lisa Daniels

Woman (uncredited)

Walker Edmiston

Voice (voice) (uncredited)

Sandra Ego

Girl (uncredited)

Victoria Paige Meyerink

Minor Role (uncredited)

Midori

Bess - Lab Technician (uncredited)

Lorna Thayer

Woman (uncredited)