The AQUARIUS working group was founded on the 6^th of May 1991 on the initiative of  students at the Institute of Aeronautics and Astronautics at Berlin University of Technology. The research and engineering group concentrates on the development and testing of hot water rocket propulsion systems for various space applications. Hot water rocket propulsion is reusable and environmentally benign, thus "green", and provides maximum safety compared to conventional chemical rocket propellants resulting in low production and operational costs. Experience gained in numerous single stage rocket launches led to the development and launch of a two stage hot water rocket for the first time in world history.

A dedicated hot water test facility has been built in order to perform firing tests for a deeper understanding of the propulsion efficiency and the influence of various nozzle parameters on exhaust characteristics. The measurement instrumentation allows for the parallel reading of temperature, pressure and thrust. For more than five years, ground-based take-off assistance systems for future reusable launch vehicles have been the subject of intensive investigation.

In addition, AQUARIUS projects are presented in the university lecture “Space Transportation Systems & Projects”. Since the beginning of its activities, AQUARIUS has been supported by Berlin University of Technology and especially by the Institute of Aeronautics and Astronautics. Furthermore, AQUARIUS has been promoted by the German Society for Aeronautics and Astronautics (DGLR) as well as the Society of Friends of Berlin University of Technology.