Browsing by Author "Skalden, Jonathan"

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Open Access
Design, development and simulation activities of an RF helicon-based plasma thruster for VLEO satellites
(2025) Papavramidis, Konstantinos; Vogt, Christopher; Gutierrez, Elizabeth; Skalden, Jonathan; Grill, Julia; Herdrich, Georg
To achieve a feasible lifetime of several years, most satellites are deployed in orbits higher than 400 km. Drag of residual atmosphere causes a slow orbit decay, resulting in the deorbit of the spacecraft. For an orbit range of 150-300 km, a solution to achieve this is the application of atmosphere-breathing electric propulsion, where the residual atmosphere is used to generate continuous thrust that compensates drag. The Institute of Space Systems developed an advanced electrode-less RF Helicon-based plasma thruster (IPT) within the EU Horizon 2020 project DISCOVERER. The electrode-less design featuring a quartz tube surrounded by an advanced RF antenna promises low sensitivity towards corrosion, low-pressure ignitability and the quasi-neutral operational regime removes the necessity of a neutralizer. Based on heritage, a new design of the thruster is being developed under the ESA ram-CLEP project. This design approach is aiming to mature the technology as a candidate suitable for a VLEO applications. This imposes several requirements and constraints such as mission and spacecraft aspects. Moreover, the design approaches for the current thruster design are depicted. First, the design concept of the thruster is described, based on given constraints and requirements, followed by a simulation analysis to achieve the required electro-magnetic performance of the antenna. Last, the final iteration of the design is concluded as well as the next design and realization steps planned to be incorporated into the system.
Open Access
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.
Open Access
Solar activity dependency of a specular intake for an ABEP system
(2025) Barth, Nadine; Skalden, Jonathan; Papavramidis, Konstantinos; Tuttas, Franziska; Pfeiffer, Marcel; Beyer, Julian; Tietz, Raphael; Fasoulas, Stefanos; Herdrich, Georg
Challenging space missions at very low altitudes face significant atmospheric drag, requiring efficient propulsion methods such as Atmosphere-Breathing Electric Propulsion (ABEP) to extend mission lifetimes. ABEP captures atmospheric particles and uses them as propellant for an electric thruster, reducing dependence on limited on-board propellant. This could extend missions in Very Low Earth Orbit (VLEO) and on celestial bodies with an atmosphere, such as Mars. The Institute of Space Systems (IRS), under the EU H2020 DISCOVERER, ESA Ram-CLEP, and CRC ATLAS projects, is developing a high-efficiency specular intake and a RF Helicon-based plasma thruster (IPT) for ABEP. This study uses the numerical tool PICLas and it’s Direct Simulation Monte Carlo Method’s (DSMC) to analyse the effect of solar activity and evaluate the validity of the hyperthermal assumption in VLEO for ABEP intake designs. Additionally, the effect of changing intake lengths on important key parameters, such as intake efficiency, mass flow rate, and pressure, is examined. The results show that efficiency decreases with higher solar activity, longer intakes and higher altitudes, with particle temperature having the greatest effect on efficiency, due to its influence on thermal velocity and the molecular speed ratio. An almost linear relationship between efficiency and molecular speed ratio is shown, revealing that the hyperthermal assumption may not be valid for VLEO applications. To achieve the required pressure level for ignition, flexible ABEP operation is recommended to accommodate for varying solar activity, suggesting lower altitude operation during low solar activity and higher altitude operation during high solar activity.