Recent Progress in Advanced Electric Propulsion at IRS

One of the program lines at IRS consists of the pulsed plasma thruster developments. This started with ADD SIMP-LEX which primarily utilizes electromagnetic forces to produce its impulse. Its solid propellant is Polytetrafluorethylene. A parallel-plate geometry was chosen. In a next step the thruster system was equipped with a proto-flight power unit which is then respectively tested and qualified together with the optimized thruster. To support and develop scaling capabilities the PPT PETRUS was developed as a thruster family i.e. in different sizes and powers. In order to maximize the thermal fraction of the thrust, particularly when low in capacitor bank energy and hence size, this thruster family is built coaxially. Moreover, the PPUs are self-developed and the developments have led to two flights i.e. with the 3U cubesat GreenCube and the 6U cubesat SONATE-2.

The thermal arcjets represent a family with powers bet 100 W and 100 kW. For the 1kW range IRS has developed and qualified thermal arcjets equipped with ALM-manufactured regeneratively cooled nozzles. Moreover, a basic research element was enabled via the manufacturing processes as a nozzle is in use where anode inserts with varying materials with different work functions are used aiming at an assessment of the impact towards e.g. the power balance of the nozzle and hence the thermal efficiency.

In order to expand the power interval to even lower powers applied field magnetoplasmadynamic (AF-MPD) thrusters are under development. Here, the breakthrough results as achieved with the 100 kW thruster SX3 have led to a program line for AF-MPDT such that a 5 kW thruster with a HTSC as well as a 1 kW thruster equipped with an advanced permanent magnet system are under development. These thrusters promising devices for orbit control of large satellites and they are suited for interplanetary missions. Both SX3 and the high power thermal arcjet HIPARC are leading developments for NEP missions which is why IRS has joined several activities in this field with particular support by ESA.

For VLEO applications and ISRU-based missions advanced bird-cage antenna equipped helicon thrusters are under development both in the frame of ESA- and EU-projects as well as in the frame of the CRC ATLAS, a multi-year (max 12 years) project cluster aiming at the promotion of VLEO based missions.