A planet is discovered in the same orbit as Earth's but is located on the exact opposite side of the sun, making it not visible from Earth. The European Space Exploration Council decide to send American astronaut Glenn Ross and British scientist John Kane via spaceship to explore the other planet.
| Directing | Robert Parrish | Director |
| Writing | Sylvia Anderson | Story |
| Writing | Sylvia Anderson | Screenplay |
| Production | Sylvia Anderson | Producer |
| Editing | Len Walter | Editor |
| Writing | Gerry Anderson | Screenplay |
| Writing | Gerry Anderson | Story |
| Production | Gerry Anderson | Producer |
| Camera | John Read | Director of Photography |
| Production | Ernest Holding | Associate Producer |
| Production | Brian Burgess | Production Manager |
| Art | Bob Bell | Art Direction |
| Sound | Barry Gray | Original Music Composer |
| Visual Effects | Derek Meddings | Visual Effects Director |
| Costume & Make-Up | Barbara Ritchie | Hairstylist |
| Costume & Make-Up | Geoffrey Rodway | Makeup Artist |
| Directing | John O'Connor | Assistant Director |
| Art | Philip Bawcombe | Assistant Art Director |
| Art | Chris Burke | Assistant Art Director |
| Sound | Ted Karnon | Sound Recordist |
| Sound | John Peverill | Sound Editor |
| Sound | Ken Rawkins | Sound Recordist |
| Costume & Make-Up | Gloria Barnes | Wardrobe Master |
| Costume & Make-Up | Elsa Fennell | Wardrobe Supervisor |
| Camera | Godfrey A. Godar | Camera Operator |
| Editing | Margaret Miller | Assistant Editor |
| Production | Ivo Nightingale | Location Manager |
| Directing | Joan Davis | Continuity |
| Production | Julie Leighton-White | Production Secretary |
| Writing | Donald James | Screenplay |
