There is no musical score for this film. Instead, each spacecraft has its own ambient soundtrack when it is shown in space. The Apollo shots feature a low hum; the XRV, a hollow ringing; the Nimbus Weather Satellite, a rapid series of beeps ascending in pitch; and the Russian Voshkhod, a constant pitch series of beeps. The only exceptions to this is are a very slight, muted bit of music played under the Apollo ambient soundtrack during Pruett's final EVA, and a single tone (with some ambient effects that could be called music) during the opening credits.
Frank Capra began work on the film. Inspired by his work on the Martin-Marietta Corp.-commissioned faux documentary, "Rendezvous in Space" for the 1964 World's Fair in New York, Capra (a chemical engineer by education) worked to make the picture for Columbia, but finally abandoned the project in preproduction in May 1966 when he couldn't bring the budget down to the $3-million required by Columbia worldwide production chief M.J. Frankovich. The eventual budget for the finished film (directed by John Sturges) was $8 million. Capra never made another film.
The space station using a spent Saturn S-IVB stage was based on early proposals during the Apollo Applications Program; at the time of filming, what came to fruition as Skylab was still under development. The only differences between the orbital workshop depicted in the film (which has a rocket motor attached) and the real Skylab was the incorporation of the Apollo Telescope Mount and two docking ports on the docking module, not to mention the absence of a rocket motor. The real Skylab was launched as a 'dry' workshop using a surplus Saturn V #SA-513 (originally earmarked for the canceled Apollo 18 mission). The three-man crew in the film spend 5 months living in space; the longest duration in the real Skylab was 84 days during the final mission, Skylab 4.
In the film, the astronauts are seen using what appears to be the early concept of the Manned Maneuvering Unit - during the real-life Skylab missions, the Astronaut Maneuvering Unit (the AMU) was tested inside the space station and never tested in the vacuum of space. The first use of the MMU was during STS-41-B (the fourth flight of the Challenger) on February 7, 1984.
The film's release (prior to the launch of Apollo 13) about a space disaster led to a real-life crisis aboard Skylab 3 (c. July -September 1973) where a thruster leak developed on board the Apollo CSM. The depiction of a rescue vehicle (the lifting body in the film) was the basis of the Skylab Rescue space vehicle, based on a Block II Apollo Command Module (CSM #119) which was modified by North American Rockwell. Memos dating back to December 1970 (from NASA facilities at the Manned Spacecraft Center in Houston, TX and Kennedy Space Center) confirm that a rescue spacecraft will be the next in line if the main Apollo CSM fails during flight. By November 1971, the modified CSM was phased in with evaluation and testing (prior to the final moon mission, Apollo 17, which launched in December 1972). The real-life thruster leak aboard Skylab 3 was neutralized and fixed where the rescue launch vehicle (piloted by NASA astronauts Vance Brand and Don Lind) was pulled from flight duty; the vehicle was on standby for Skylab 4 and the Apollo-Soyuz mission. Brand would fly on the Apollo-Soyuz mission and Lind on STS-51B in 1985. Since the final Apollo flight in 1975 (with Apollo-Soyuz), the modified command module, CSM #119, has been on display @ the Kennedy Space Center's Visitors Complex. NASA engineers have studied the modified Skylab Rescue CSM for the Orion Spacecraft (part of Project Constellation), which will replace the Space Shuttle after its final flight in 2010.
Was the impetus behind the 1975 Apollo-Soyuz Test Project where American astronauts and Soviet cosmonauts docked in space.
The Film Ventures International re-edit of this film (retitled "Space Travelers") was featured on an episode of Mystery Science Theater 3000. This was also the only film featured on the show to have won an Academy Award.