Who flew on more Space Shuttle missions, meteorologist Piers Sellers or chemical engineer Lodewijk van den Berg?
Lodewijk van den Berg Lodewijk van den Berg (] ; born March 24, 1932) is a Dutch American chemical engineer, specializing in crystal growth, who flew on a 1985 Space Shuttle "Challenger" mission as a Payload Specialist.
Gregory C. Johnson Gregory Carl "Ray J" Johnson (born July 30, 1954), (Capt, USNR, Ret.), is a former American naval officer and aviator, test pilot, aerospace engineer, and NASA astronaut. He spent his military career in both, the United States Navy and the Navy Reserve. He was the Pilot on Space Shuttle mission STS-125, the final Hubble Space Telescope servicing mission.