A System Concept Study and Experimental Evaluation of Miniaturized Electrodynamic Tethers to Enhance Picosatellite and Femtosatellite Capabilities.

electrodynamic tether;small spacecraft;Electrical Engineering;Engineering;Electrical Engineering

Bell, Iverson C.Gallimore, Alec D. ;

University of Michigan

关键词: electrodynamic tether;    small spacecraft;    Electrical Engineering;    Engineering;    Electrical Engineering;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/113575/icbell_1.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

The work presented in this thesis evaluates the potential of electrodynamic tether (EDT) propulsion technology to provide picosatellites (100 g–1 kg) and femtosatellites (<100 g) with orbital maneuvering capability. The miniaturized EDT concept considered in this dissertation is a fundamentally novel paradigm because it is much shorter than a conventional EDT, with total length of about 10 meters, and it considers the use of a semi-rigid tether. A detailed trade study is presented that explores the feasibility of using EDTs for small satellite drag make-up and propulsion. The trade study includes the development of a system concept and mission scenario. Three example small spacecraft were considered in this study: a 200-g planar picosat, a 150-g cubic picosat, and a 10-g ;;ChipSat.;; The results reveal that an insulated tether only a few meters long can provide these spacecraft with complete drag cancellation and the ability to change orbit. All of the spacecraft were able to generate a thrust force that exceeded drag at 500 km and 600 km, assuming a circular, equatorial orbit. EDT thrust estimates were made for a set of particular, but representative, cases and a few simplifying assumptions were made to facilitate estimating tether current. In order to evaluate electron current collection, ground-based plasma experiments were conducted to capture key characteristics of the satellite-low-Earth-orbit (LEO) interaction. Tests were performed to investigate current collection in a flowing plasma and observe changes in collection due to (a) probe orientation relative to plasma flow and (b) magnetic field strength. The laboratory data were analyzed to develop expressions for the current collection behavior of picosats and femtosats. The data indicated that the WLP-based collection model could be refined with small modification to the thrust estimates. It was also determined that the anode;;s current collection characteristic would be impacted by the orientation of the spacecraft relative to the magnetic field and the direction of motion depending on the shape of the anode.