Final answer:
Ronald McNair was an American physicist and NASA astronaut who died in the Challenger space shuttle disaster on January 28, 1986, which marked a significant moment in space exploration history and led to major changes in NASA's safety protocols.
Step-by-step explanation:
Ronald McNair was an American physicist and NASA astronaut who is remembered for his tragic death in the Challenger space shuttle disaster. On January 28, 1986, McNair was one of the seven crew members aboard the Space Shuttle Challenger when it broke apart shortly after takeoff, leading to the death of all on board. This event marked a significant moment in space exploration history, showcasing both the inherent risks of space travel and instigating major changes in NASA's safety protocols.