Satellites typically weigh around several hundred kilograms. A large proportion of this weight is accounted for by the fuel, either in liquid or gas form. Rocket operators have to shoulder high costs to get them into space. The Chair of Space Systems at TU Dresden is therefore working with other international universities and various companies to research fuel-free propulsion systems for space satellites.

With conventional propulsion systems, up to 90 percent of the satellite's mass is accounted for by fuel, depending on the mission in question. The propulsion system developed as part of the E.T.COMPACT project ("Compact and Propellant-Less Electrodynamic Tether System Based on In-Space Solar Energy") has the potential to considerably reduce satellite costs while significantly increasing the proportion of usable satellite mass, for example for scientific experiments, antennas or cameras.

What makes the new drive system special is that it only uses solar energy. Long, conductive strips, known as electrodynamic tethers, are attached to the satellite. When moving through the earth's magnetic field, these tethers induce a voltage. This creates a closed circuit between the tether and the surrounding plasma atmosphere (ionosphere). The force acting upon the conductive strip is known as the Lorentz force. This principle is also used in traditional electric motors. Tandem solar cells store the electrical energy generated. They consist of two photovoltaic solar cells made of the materials CIGS (copper indium gallium diselenide) and perovskite.

One of the biggest challenges in this process is completing the electrical circuit. Researchers at the Institute of Aerospace Engineering are therefore developing innovative, propellant-free electron emitters. These emitters enable the electrons to leave the conductor band in the direction of the atmosphere and therefore close the circuit. The electron emitters are currently being developed and tested in the space simulation chambers of the Chair of Space Systems.

The E.T.COMPACT project will run for three years and is funded by the European Innovation Council (EIC) as part of the Pathfinder program.

Contact

Prof. Martin Tajmar
Chair of Space Systems
TU Dresden
Phone: 0351 463-38091
Email: