How many people are lost in space till now?

I'm curious, could you elaborate on the intriguing topic of individuals who have been lost in space? Specifically, how many individuals have we tragically lost in the vast expanse of the universe up until this point in time? It's a sobering thought to consider the bravery and sacrifice of those who ventured forth into the unknown, only to never return. What measures are being taken to prevent such tragedies from occurring in the future, as we continue to push the boundaries of space exploration?