Hans Schlegel is a physicist, an astronaut of the German Space Agency (DLR) and then a member of the European Space Agency Astronaut Corps. He first flew as a scientist-astronaut for the German D2 Spacelab mission on Space Shuttle mission STS-55 (1993). He then prepared as a backup crew for the German-Russian MIR-97 mission, for which he was trained by Dr Kass to perform a series of experiments with the Modular Physiological Laboratory, MEDEX, which was flown on this mission. This training was carried out in Germany as well as at Gagarin Cosmonaut Training Centre in Star City, near Moscow.
Afterwards he received additional training in Russia to become qualified as a second board engineer for the Mir space station. His second space flight was on the Space Shuttle STS-122 to the International Space Station.