Three cosmonauts have died during the space shuttle landing in Union 11 space mission. Shuttle was landed successfully, but all cosmonauts were dead due to depressurization of the cabin. That accident could be avoided if cosmonauts were wearing space suit, but Union 11 space shuttle was projected only for one cosmonaut. Soviet Union's government sent three people, because NASA did this.

Cosmonauts: Georgi Dobrovolski, Vladislav Volkov, Viktor Patsayev.