Question: Who flew on more Space Shuttle missions, meteorologist Piers Sellers or chemical engineer Lodewijk van den Berg?
Sentence (from "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.
Relevant evidence: Yes