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Electric propulsion systems

Good communication requires precise positioning

The main research fields of the SeRANIS project deal with the communication and transmission of data. Regardless of the technology used, the satellites need to be accurately positioned to ensure fast and efficient communication. For such purposes, electric propulsion systems have proven effective thanks to the precise adjustment options of the generated forces and due to their high efficiency. The advantage of electric spacecraft propulsion systems in comparison to other types of drive system is their high specific impulse, which requires very small amounts of propellant. This makes these systems particularly attractive for long-term missions. This gives reason to explore solutions for existing problems such as grid erosion in ion thrusters or the scalability of Hall-effect thrusters but also to develop new drive concepts.

Core objectives and unique feature

At the Institute for Plasma Technology and Mathematics at the Universität der Bundeswehr, two drive concepts – C-Star and HERVAT – have been designed for positioning satellites and tested under laboratory conditions. The first concept is based on a capacitively-coupled radio frequency discharge, where the charged particles of a quasi-neutral plasma are accelerated by means of magnetic fields. As a result, a C-Star drive does not require any additional components that would prevent build-up of static charge on the satellite (referred to as neutralizers). The concept is scalable and has a long life due to the absence of a cathode. In addition, a C-Star drive can work with different types of fuel, which is not only more environmentally friendly but also makes it possible to reduce running costs. The second concept (HERVAT) is a vacuum discharge system that is most notably characterized by its simple structure and, like the C-Star, does not require a neutralizer. Originally developed for microsatellites (Cube Sat), this system has been tested under laboratory conditions to carry out more than 10 million position-correcting pulses with one tiny unit.

The SeRANIS project provides a basis for exploring the concepts developed under laboratory conditions under real field conditions. In the process, both drive systems are adapted to the size of the satellite and the on-board conditions, and undergo a series of qualification tests in order to obtain flight certification.

What do we aim to achieve?

Essentially, the purpose of the SeRANIS project is to put into practice the knowledge acquired through scientific research about the physics of electric drives. The expert knowledge acquired from the project – in particularly with regard to the constructive implementation and flight certification of electric spacecraft drive systems – is thus an important factor for the development of future drive concepts. In addition, the project provides a basis for students and young researchers to gain significant experience for their ensuing military, university or industrial careers.

Participating institutes

Institute for Plasma Technology and Mathematics


Prof. Dr.-Ing. Jochen Schein