Who flew on more Space Shuttle missions, meteorologist Piers Sellers or chemical engineer Lodewijk van den Berg?
Piers Sellers Piers John Sellers OBE (11 April 1955 – 23 December 2016) was a British-American meteorologist, NASA astronaut and Director of the Earth Science Division at NASA/GSFC. He was a veteran of three space shuttle missions.
Mark T. Vande Hei Mark Thomas Vande Hei (born November 10, 1966) is a current NASA astronaut selected in 2009, who launched to the International Space Station on September 12, 2017 for his first spaceflight.