Soyuz 21

The Soviet Union launches cosmonauts Boris Volynov and Vitaly Zholobov aboard Soyuz 21, the first mission to the newly-orbited Salyut 5 military space station. Though a few scientific experiments are conducted, most of the crew’s activities involve military surveillance of Earth. The crew’s stay is intended to last as long as two months, though an emergency aboard the station will cut that stay short.