In 1975 American and Soviet spacecraft docked together in orbit as part of the Apollo–Soyuz Test Project (ASTP), the world's first international crewed space mission. Focussing on the project's political symbolism, this article argues that the ASTP was an attempt by the Nixon and Ford administrations to advertise US–Soviet detente by harnessing the optimistic imagery of “space brotherhood,” an instinctive kinship supposedly shared by American astronauts and Soviet cosmonauts. This was ultimately unsuccessful, as detente's critics appropriated the mission for their own symbolic use to attack US–Soviet detente as a fantastical escape from earthly problems.