• solar thermal propulsion

Solar thermal propulsion (STP) is an advanced space propulsion technology wherein solar power is used to directly heat the propellant. It potentially allows for achieving specific impulse levels beyond 900 seconds, which is about twice that of the best performing chemical systems and thruster efficiency in the range of 80% seems feasible. In the frame of research on thermal space propulsion at the faculty of Aerospace Engineering at the Delft University of Technology a ground demonstrator has also been developed and tested by Harrie Leenders and B.T.C. Zandbergen. As a next step toward a space qualified STP system it is considered to develop a miniature space demonstrator of a size that fits on board of a future Delfi cube – nanosatellite. This work deals with the preliminary design of a STP technology demonstration experiment. The resulting design uses Fresnel lenses as solar collectors and optical fibres to transfer the energy to the thruster where it is used to heat up the propellant. The thrust level is in the order of 0.6mN while specific impulse is about 160s. Total volume is smaller than 50cm3. Because the system is a technology demonstrator is not optimized for maximum performance. High propellant temperature is the main goal but the thrust and the specific impulse are low due to the limitations on maximum thrust and on the use of water as propellant.