Donald Sutherland as Frank Lansing

Vanessa Redgrave as Heddi Lindquist

Richard Widmark as Otto Gerran

Christopher Lee as Lechinski

Barbara Parkins as Judith Rubin

Lloyd Bridges as Smithy

Lawrence Dane as Paul Hartman

Patricia Collins as Inge Van Zipper

Michael J. Reynolds as Heyter

Nicholas Cortland as Jungbeck

August Schellenberg as Marine Technician

Candace O'Connor as Laboratory Assistant

Joseph Golland as Meteorological Assistant

Bruce Greenwood as Technician (Tommy)

Richard Wren as Radio Operator

Hagan Beggs as Larsen

Michael Collins as Ship's Captain

Robert Stelmach as Ship's Radio Operator

Terry Waterhouse as Helicopter Crewman

Mark Jones as Cook