Hydronaut Project Deep Lab 03 is a unique underwater lab that serves as a research facility for training of survival in limited and extreme environments. This underwater habitat’s controlled atmosphere allows for examination of influences of pressure, dampness, CO2, long-term stress, artificial lighting, or isolated environment on the human organism, materials, devices, and biological materials. The station enables a three-member crew long-term stay (stretching over several weeks) under the water surface. Its unique construction combining the caisson principle and submarine allows for a maneuverable vertical motion; during the mission, the crew can leave the station wearing diving gear to carry out tasks under the water surface. Leaning on the support team, with 24/7 contact with Mission Control that is in charge of regular checks of the facility’s technical and living conditions, the crew is briefed through an own communication and project management online system, fully secured and decentralized. Hydronaut Deep Lab 03’s key feature rests in its applicability for planning of certain space missions and their aspects, as well as space research since the station cannot be evacuated immediately without endangering the lives of the crew due to the risk of the so-called caisson disease (decompression sickness). That said, planning such simulated space missions requires that a staged decompression ascent in the return module lasting several hours be taken into consideration. Hydronaut Project is the official supplier of the European Space Agency (ESA Bic). Furthermore, it collaborates with Czech Technical University in Prague, the National Institute of Mental Health CR, and receives kind support from The European Structural and Investing Funds Operation Programme of the city of Prague. Should you be interested in any means of collaboration, do not hesitate and get in touch with the Project Manager: Mr. Jiri Schneider jiri.schneider@hydronaut.eu