Doppelgänger, known outside of Europe as Journey to the Far Side of the Sun, is a 1969 British sci-fi film directed by Robert Parrish, produced by Gerry and Sylvia Anderson (Stingray, Thunderbirds, Captain Scarlet and the Mysterons), and starring Roy Thinnes, Ian Hendry, Lynn Loring, Patrick Wynmark, Loni von Friedl, and Herbert Lom.
Set in 2069, the film concerns a joint European-NASA mission to investigate a newly-discovered planet that lies opposite Earth on the other side of the Sun. The mission ends in disaster and the death of one of the astronauts, after which his colleague comes to believe that the planet is a mirror image of Earth.
Includes examples of the following tropes:
- Cool Car: The futuristic-looking cars and six-wheeled jeeps used on both Earths. Some of these vehicles would re-appear in the Andersons' later series UFO.
- Cool Plane: The VTOL-capable NASA transport with a detachable cargo pod and the EUROSEC transport resembling a futuristic B-52 with a dorsal "accordion" structure.
- Cool Spaceship: The Phoenix interplanetary spacecraft and the Dove lifting body, not to mention the Saturn V-inspired launch vehicle, all certainly qualify as such.
- Counter-Earth: The premise is that astronauts discover such a world that not only looks like Earth, but everything that happens on Earth also happens there, like mirror images, including the astronauts' landing. The ultimate failure of the mission hinged upon an uncertainty as to whether or not electrons would flow in the same direction on both Earths. They do, but the scientists who built the replacement spacecraft bet the other way, causing the replacement lander to not be compatible with the mother ship. Some laws of physics are still fundamental no matter which side of the mirror you're on.
- Exty Years from Now: 2069 would be exactly 100 years in the future at the time of filming.
- Human Popsicle: Ross and Kane are placed in suspended animation for their outbound journey, being revived three weeks later when they reach the counter-Earth.
- No New Fashions in the Future: Despite the story taking place in the late 21st century, there's a very 1960s look to the character's wardrobe.
- Stuff Blowing Up: Ross crashes the replacement lander into a parked spacecraft, killing him and causing a chain reaction that destroys most of the Space Centre and all records of his presence on the counter-Earth.
- Technology Porn: This being a Gerry Anderson production, there's bound to be some pretty nice equipment. See Cool Car, Cool Plane, and Cool Spaceship for specific examples.