While the mission itself was considered a success, a catastrophic depressurization during re-entry resulted in the deaths of all three cosmonauts: Georgi Dobrovolsky, Vladislav Volkov, and Viktor Patsayev.
It's important to note that this was the first manned mission where deaths occurred. There were unmanned missions, such as the Apollo 1 fire during a launchpad test, where astronauts tragically lost their lives.
