| Name | Character | Episodes |
|---|---|---|
| Richard Dillane | Wernher von Braun | 4 |
| Steve Nicolson | Sergey Korolyov | 4 |
| Ravil Isyanov | Valentin Glushko | 4 |
| Robert Lindsay | 4 | |
| Stephen Greif | 4 | |
| Todd Boyce | Alan Shepard | 4 |
| John Warnaby | Mishin | 4 |
| Mikhail Gorevoy | Serov | 2 |
| Mariya Mironova | Nina Korolev | 2 |
| Tim Woodward | Nedelin | 2 |
| Oleg Stefan | 1 |