Pin is about the Soyuz 33 Interkosmos space mission with Bulgaria.
Soyuz 33 was a 1979 Soviet manned space flight to the Salyut 6 space station. It was the ninth mission to the orbiting facility, but an engine failure forced the mission to be aborted, and the crew had to return to earth before docking with the station. It was the first ever failure of a Soyuz engine during orbital operations.
The two-man crew, commander Nikolai Rukavishnikov and Bulgarian cosmonaut Georgi Ivanov, suffered a steep ballistic re entry, but were safely recovered. Rukavishnikov was the first civilian to command a Soviet spacecraft, and Ivanov the first Bulgarian in space.
Interkosmos was a Soviet space program, designed to help the Soviet Union’s allies with manned and unmanned space missions. The program included the allied east European nations of the Warsaw Pact and other socialist nations like Afghanistan, Cuba, Mongolia, and Vietnam. In addition, pro Soviet nations such as India and Syria participated, and even France and Austria, despite them being capitalist nations.