- Gregory Peck
- Charles Keith
- Richard Crenna
- Jim Pruett
- David Janssen
- Ted Dougherty
- James Franciscus
- Clayton Stone
- Gene Hackman
- Buzz Lloyd
- Lee Grant
- Celia Pruett
- Nancy Kovack
- Teresa Stone
- Mariette Hartley
- Betty Lloyd
- Scott Brady
- Public Affairs Officer
- Frank Marth
- Air Force Systems Director
- Craig Huebing
- Flight Director
- John Carter
- Flight Surgeon
- Vincent Van Lynn
- Aerospace Journalist
- George Gaynes
- Mission Director
- Tom Stewart
- Houston Cap Com
- Duke Hobbie
- Air Force Titan Specialist
- Walter Brooke
- Network Commentator
- Dennis Robertson
- Launch Director
- Don Ames
- Reporter
- Dick Cherney
- Engineer
- Bill Couch
- Russian Cosmonaut
- Brent Davis
- Air Force Captain
- Matt Emery
- Texas State Trooper
- John Forsythe
- Olympus / President (uncredited)
- Robert Hitchcock
- Guest in Observation Room
- Mauritz Hugo
- Hardy - Reporter
- Kenner G. Kemp
- Guest in Observation Room
- John S. Ragin
- Simulator Technician
- Mary Linda Rapelye
- Priscilla Keith
- Bruce Rhodewalt
- Computer Technician
- George R. Robertson
- VIP
- Clark Ross
- Reporter
- John Roy
- Guest in Observation Room
- Eddie Smith
- Reporter
- George Smith
- Cape Weather Officer
- Robert Strong
- Engineer
