50 years ago today was the launch of the first Soyuz spacecraft. Although there have been technical innovations it is still the same basic design as it was 50 years ago, making it the most important and longest-lived workhorse in space flight. The international space station still always has a Soyuz capsule docked in case it is needed.
Currently Soyuz is the only way to get to and from the station.
The first flight ended in disaster, and the death of cosmonaut Vladimir Komarov after a parachute failure. Both he and Yuri Gagarin (the backup pilot) were aware that there were technical problems and that the flight was rushed. Gagarin attempted to bump Komarov in the hopes that the government would delay the launch rather than risk the life of a national hero, but Komarov refused.