1. 1Division Space Physiology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne
2. 2Department of Orthopaedic Trauma, RWTH Aachen University, Aachen
3. 3Space Medicine Office, Directorate of Human Spaceflight and Operations (D/HSO), European Astronaut Center, European Space Agency, Cologne
4. 4Institute for Pattern Recognition, Hochschule Niederrhein, Krefeld
5. 5Department of Radiology and
6. 6Department of Orthopaedic and Trauma Surgery, University of Cologne, Cologne, Germany