A team of American astronauts leave their space station on the first mission to Mars, but the captain's religious beliefs may get in the way.
| Actor | Role |
|---|---|
 Walter BrookeGen. Samuel T. Merritt | Gen. Samuel T. Merritt |
 Eric FlemingCapt. Barney Merritt | Capt. Barney Merritt |
 Mickey ShaughnessySgt. Mahoney | Sgt. Mahoney |
 Phil FosterJackie Siegle | Jackie Siegle |
 William RedfieldRoy Cooper | Roy Cooper |
 William HopperDr. George Fenton | Dr. George Fenton |
 Benson FongImoto | Imoto |
 Ross MartinAndre Fodor | Andre Fodor |
 Vito ScottiSanella | Sanella |
 John DennisDonkersgoed | Donkersgoed |
 Michael FoxElsbach | Elsbach |
 Joan ShawleeRosie McCann | Rosie McCann |
 Iphigenie CastiglioniMrs. Heinz Fodor | Mrs. Heinz Fodor |
 Rosemary ClooneyMusical Number (archive footage) (uncredited) | Musical Number (archive footage) (uncredited) |