Complex sentence: Francis Richard "Dick" Scobee (May 19,1939-January 28,1986) was an American astronaut who was killed commanding the Space Shuttle Challenger, which suffered catastrophic booster failure during launch of the STS-51-L mission.
Split into simpler sentences: Francis Richard "Dick" Scobee (May 19,1939-January 28,1986) was an American astronaut. He was killed commanding the Space Shuttle Challenger, which suffered catastrophic booster failure during launch of the STS-51-L mission.