NanoPPU100

Starting point / motivation

For almost a decade, FOTEC has been developing mN-FEEP (Field Effect Electric Propul-sion) thrusters, poised to be used in future ESA missions. These thrusters are distinguished by their ability to provide highly accurate thrust levels ranging from 1 µN to more than 1 mN at very high specific impulses of roughly 5000 s. FEEP thrusters allow large satellites to control their position with unprecedented accuracy, thereby enabling delicate precision-manoeuvres, such as formation flight of scientific satellites. In fact, the crownemitter being at the heart of a FEEP thruster was originally developed by FOTEC to enable fixed formation flight for the future ESA NGGM mission.

Contents and goals

As the need for propulsion systems for micro- and nanosatellites became an urgent matter, it has been realized that mN-FEEP thrusters could also be employed to significantly increase the mission range of such small satellites by continuous drag compensation. Alternatively, the high specific impulse allows for very high delta-v manoeuvres at a high propellant mass utilization efficiency.

Methods

In order to adapt the thruster for the demands of increasingly popular Cu-beSat missions, the housing had to be redesigned. In parallel, a power processing unit (PPU) has been developed and integrated into the thruster module. The result is a highly performant and compact thruster module that includes the whole thruster subsystem including the PPU, propellant, and neutralizers in a 1 dm³ package weighing around 800 g.

In the near future, the successful IFM Nano thruster module shall not only be used for nano satellites but also on larger spacecraft, necessitating an increase of the ion beam power from currently 25 W to 75 W. The present PPU, however, is not capable of delivering sufficient power for such an application.

As, despite the higher power output, a small form factor (cur-rently 90 x 94 mm x 19 mm) has to be maintained, a complete redesign of the PPU including an adapted thermal concept is required. Another angle is to reduce losses associated with the heating of the liquid indium propellant, so as to minimise the amount of required heater power.

A third issue is the unavoidable heat being generated by the PPU components themselves, which has to be removed from the module efficiently, thereby necessitating an improved thermal management system.

During the proposed project, the IFM Nano Thruster PPU shall be redesigned from the ground up in order to minimize electronic losses. For the thermal management, several technolo-gies - including thermal straps, conventional and 3D-printed heat pipes - shall be evaluated and the best solution shall be identified. In addition, thermal losses within the housing shall be analysed and minimized by coatings, thermal shielding or insulation.

Expected results

Eventually, the efforts shall result in a reliable and efficient 100 W PPU capable of driving In-FEEP modules with 75 W beam power, to be used in the next generation of mN-FEEP thrusters on several future ESA missions.

Coordinator

FOTEC Forschungs- und Technologietransfer GmbH

Project partner

ENPULSION GmbH

FOTEC Forschungs- und Technologietransfer GmbH
Dr. Christoph Buchner
Viktor Kaplan-Strasse 2
A-2700 Wiener Neustadt