with the European Space Agency (ESA). He was payload specialist aboard the space shuttle Columbia in April and May 1993 as part of the German-sponsored Spacelab D-2 mission. Schlegel began training as an astronaut in 1988 at the Deutsches Zentrum für Luft- und Raumfahrt (DLR; German Aerospace Centre). He became an ESA astronaut in 1998, and in the same year began training at NASA's Johnson Space Center as a mission specialist. He has since worked on mechanical systems, crew equipment, and robotic issues in the Astronaut Office at the Johnson Space Center.