Skylab-SalyutWith planning already well underway for the Apollo-Soyuz mission which won’t take place until 1975, NASA commissions a study from McDonnell Douglas to explore the feasibility of a follow-up to the international space mission, possibly involving joining the backup of the Skylab space station (known as “Skylab B”) and a yet-to-be-launched Soviet Salyut space station at some point in the latter half of the 1970s, effectively creating a joint international space station. Although the study goes so far as to specify issues of concern regarding the structure of the two stations and their respective standard atmospheric pressures, the recommendations are shelved pending the outcome of the Apollo-Soyuz flight. Significant political developments in the late 1970s will prevent the idea of an international station from moving forward for at least a quarter century.