STS055-45-017 (26 April-6 May 1993) --- Hans Schlegel (foreground) participates in the ongoing investigation of human physiology under microgravity conditions as he works out on the ergometer at the Anthrorack. Monitoring the "run" is astronaut Bernard A. Harris, Jr., STS-55 mission specialist. Schlegel is one of two payload specialists representing the German Aerospace Research Establishment (DLR) on the Spacelab D-2 mission.