1971-06-06 USSR Soyuz 11

Photo: The Soyuz 11 crew, Georgi Dobrovolski (left), Vladislav Volkov (right) and Viktor Patsayev (background).
Soyuz 11 was the only crewed mission to board the world's first space station, Salyut 1 (Soyuz 10 had soft-docked, but had not been able to enter due to latching problems).The crew, Georgy Dobrovolsky, Vladislav Volkov, and Viktor Patsayev, arrived at the space station on 7 June 1971, and departed on 29 June 1971. The mission ended in disaster when the crew capsule depressurised during preparations for re-entry, killing the three-man crew. The three crew members of Soyuz 11 are the only humans to have died in space.

Launch of Soyuz 11 on June 6, 1971.
Soyuz 11 docking with with Salyut 1 on June 7, 1971.
Return of Soyuz 11 on June 29, 1971.
Soyuz 11 stamp on first day cover, issued on October 20, 1971.
(Reference from Soyuz 11)