06 Fakultät Luft- und Raumfahrttechnik und Geodäsie

Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/7

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Publication Type: search.filters.UBSTyp.ZeitschriftenartikelAuthor: search.filters.author.Herdrich, GeorgAuthor: search.filters.author.Ehresmann, ManfredInstitute: search.filters.UBSInstitut.Institut für RaumfahrtsystemeInstitute: search.filters.UBSInstitut.Fakultätsübergreifend / Sonstige EinrichtungSubject: search.filters.subject.620

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Now showing 1 - 4 of 4
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    Cluster of electric thrusters for astronautic and robotic INPPS flagship space flights to Mars and Europa moon
    (2023) Jansen, Frank; Andreussi, Tommaso; Cesarretti, Giovanni; Ehresmann, Manfred; Grill, Julia; Herdrich, Georg; Funaki, Ikkoh; Girard, Nathalie; Grundmann, Jan Thimo; Krejci, David; Leiter, Hans; Masson, Frederic; Maiwald, Volker; Misuri, Tommaso; Oriol, Stephane; Piragino, Antonio; Reissner, Alexander; Schanz, Lars
    This review deals with the selection of the electric propulsion system (EPS) for the internationally developed and designed, primary nuclear-electric space tug International Nuclear Power and Propulsion System (INPPS). INPPS is scheduled for interplanetary missions to Mars and Jupiter moon Europa missions by the end of decade 2020. Regarding specific technical and mission parameters preselected electric thruster (ET) types, developed by international companies and institutions, are analysed, evaluated and investigated for a possible application as propulsion system (PS), the so-called CET (Cluster of Electric Thrusters). It is analysed whether solely electric thrusters, combined in an adequate CET, enable the envisaged interplanetary missions-robotic and astronautic/crewed with the INPPS flagship. Thruster clusters with strategic consortium considerations are analysed as a feasible PS of the INPPS. The studied CET consists of the following: (a) only European ETs, (b) combination of German and European ETs, (c) Japanese and European ETs or at least (d) Japanese, European and US thrusters. The main results are (1) Robotic and crewed INPPS mission to Mars/Europa are realizable with EPS only (no chemical propulsion is needed), (2) that every CET, except (c) of only Japanese and part of European thrusters, is capable to perform the main part of envisaged INPPS flagship mission orbit to Mars, back to Earth and to Jupiter/Europa moon.
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    Development of a ferrofluid-based attitude control actuator for verification on the ISS
    (2024) Zajonz, Sebastian; Korn, Christian; Großmann, Steffen; Dietrich, Janoah; Kob, Maximilian; Philipp, Daniel; Turco, Fabrizio; Steinert, Michael; O’Donohue, Michael; Heinz, Nicolas; Gutierrez, Elizabeth; Wagner, Alexander; Bölke, Daniel; Sütterlin, Saskia; Schneider, Maximilian; Remane, Yolantha; Kreul, Phil; Wank, Bianca; Buchfink, Manuel; Acker, Denis; Hofmann, Sonja; Karahan, Bahar; Ruffner, Silas; Ehresmann, Manfred; Schäfer, Felix; Herdrich, Georg
    Ferrofluid-based systems provide an opportunity for increasing the durability and reliability of systems, where mechanical parts are prone to wear and tear. Conventional reaction control systems are based on mechanically mounted rotating disks. Due to inherent friction, they suffer from degradation, which may eventually lead to failure. This problem is further intensified due to the limited possibility for repair and maintenance. Ferrofluid-based systems aim to replace mechanical components by exploiting ferrofluidic suspended motion. Ferrofluids consist of magnetic nanoparticles suspended in a carrier fluid and can be manipulated by external magnetic fields. This paper describes the working principle, design, and integration of a working prototype of a ferrofluid-based attitude control system (ACS), called Ferrowheel. It is based on a stator of a brushless DC motor in combination with a rotor on a ferrofluidic bearing. The prototype will be verified in a microgravity environment on the International Space Station, as part of the Überflieger 2 student competition of the German Aerospace Center. First ground tests deliver positive results and confirm the practicability of such a system.
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    Fargo : validation of space-relevant ferrofluid applications on the ISS
    (2024) Sütterlin, Saskia; Bölke, Daniel; Ehresmann, Manfred; Heinz, Nicolas; Dietrich, Janoah; Karahan, Bahar; Kob, Maximilian; O’Donohue, Michael; Korn, Christian; Grossmann, Steffen; Philipp, Daniel; Steinert, Michael; Acker, Denis; Remane, Yolantha; Kreul, Phil; Schneider, Maximilian; Zajonz, Sebastian; Wank, Bianca; Turco, Fabrizio; Buchfink, Manuel; Gutierrez, Elizabeth; Hofmann, Sonja; Ruffner, Silas; Wagner, Alexander; Breitenbücher, Laura; Schäfer, Felix; Herdrich, Georg; Fasoulas, Stefanos
    The Ferrofluid Application Research Goes Orbital (FARGO) project desires to harness the potential of ferrofluids for advanced space system applications. Thereby, the student-led research project aims to develop, evaluate and subsequently validate three different ferrofluid-based applications on board the International Space Station (ISS): a novel attitude control system called Ferrowheel as well as a Thermal and an Electrical Switch. The project is part of the Überflieger2 competition of the German Aerospace Center (DLR) in cooperation with the Luxembourg Space Agency (LSA). Central to this study is the role of ferrofluids in ensuring the functional principles to minimize the number of moving components ultimately. Therefore, the proposed systems have the potential to mitigate wear, reduce friction, and consequently improve the longevity and reliability of space systems. In the Ferrowheel, a disc is supported on ferrofluid cushions instead of conventional ball-bearing-mounted rotors. This innovative approach, facilitated by the magnetic pressure positioning of the ferrofluid, eliminates the need for solid-to-solid contact. Circularly arranged coils function as the stator, propelling the disc with a 3-phase control, resulting in a spinning magnetic field. In addition to determining the generated torque, the objective is to validate experiments on system operations in which various acceleration and deceleration manoeuvres, as well as the stored angular momentum, are evaluated. The Electrical Switch leverages a self-manufactured magnetorheological fluid (MRF) developed by augmenting a liquid-metal base with iron powder. As a result, the fluid, akin to ferrofluid, has a magnetic field-responsive movement. Since a liquid metal is used as the base, the ferrofluid-like fluid acts as both the magnetically actuatable and the current conducting fluid. To enable a current flow, the fluid is brought between the two electrical contacts utilizing electropermanent magnets (EPMs). These magnets combine the high magnetic field strengths of permanent magnets with the adaptive switching capability of electromagnets. Compared to all other demand-controlled magnetic field sources, this results in the great advantage that no energy is consumed as long as they are in one state. Only the switching process of the EPMs itself requires a high amount of energy, but only for a relatively short period. The switching behaviour under different loads will be investigated, evaluated, and compared to reference data recorded on Earth. The design of the Thermal Switch is characterized by the fact that it can be actively switched. Active thermal switching is still a relatively new field, so there is little comparative data from industrial solutions. Particularly for spacecraft, thermal design is crucial because the harsh environment of space must be taken into account. In addition to the challenge that heat can only be transferred to the environment via thermal radiation, severe conditions in space are characterized by extreme temperature differences. While extreme heat develops on the satellite surface on the side facing the sun, the opposite is valid on the shaded side. The resulting heat flow, which is irregular in time, location, and direction, leads to temperature peaks and gradients that can affect the system’s performance, functionality, and reliability. Active switching provides selective control over heat transfer, allowing more flexible temperature regulation in critical areas and implementing a dynamic system response. Different design ideas are tested and evaluated for the applications in various experiments. The most suitable design is finally selected, further modified, and tailored for experimentation on the ISS and presented in this study. The most significant challenge is the time-critical factor of only a 1-year development phase. A total of 21 students from six different courses of study and two supervising PhD students from the Institute of Space Systems are involved in the FARGO project, all members of the small satellite student society at the University of Stuttgart, KSat e.V.
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    Neutron imaging investigation of additively manufactured tungsten nozzles for an arcjet deorbit system
    (2025) Skalden, Jonathan; Ehresmann, Manfred; Becatti, Giulia; Schulz, Michael; Gustschin, Alex; Rebelo Kornmeier, Joana; Kis, Zoltán; Szentmiklósi, László; Herdrich, Georg
    The Institute of Space Systems is currently developing a deorbit module based on thermal arcjet technology to allow fast orbit decay at end-of-life, with a focus on megaconstellation satellites. By employing additive manufacturing with tungsten, improved nozzle geometries can lead to a gain in overall performance. However, reproducibility is an ongoing concern for additively manufactured parts. Together with the Heinz Maier-Leibnitz Zentrum (MLZ) and the Budapest Neutron Centre of the Centre for Energy Research, a study was conducted scanning additively manufactured arcjet nozzles prior to and after standardized operation via neutron computed tomography. The results show a drop in performance over time, which can be related to changes in the constrictor geometry. Furthermore, cavities created during manufacturing can significantly influence operation.