Martin Grabe
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View article: Ground-based experimental study on the contamination potential of a freely expanding 10 N bi-propellant thruster plume
Ground-based experimental study on the contamination potential of a freely expanding 10 N bi-propellant thruster plume Open
Satellite thruster plume constituents pose a challenge when it comes to estimating their potential to degrade or contaminate spacecraft surfaces. Therefore, ESA has commissioned a study that covers the characterization of two European bi-p…
View article: Development and characterization of the ALFVEN thruster
Development and characterization of the ALFVEN thruster Open
The Advanced Linear Field Vector Excitation Network (ALFVEN) thruster represents a novel RF plasma propulsion system developed to enhance the coupling efficiency of electromagnetic waves to plasma, particularly in low-power conditions. Thi…
View article: Comparative study of electron temperature and ion energy in two different magnetic nozzle thruster designs
Comparative study of electron temperature and ion energy in two different magnetic nozzle thruster designs Open
Conventional ion thruster technologies face challenges such as electrode and grid erosion and the need for additional neutralizer devices. In this article, we discuss two thruster concepts that achieve plasma acceleration by means of a mag…
View article: Comparative Study of Electron Temperature and Ion Energy in Two Different Magnetic Nozzle Thruster Designs
Comparative Study of Electron Temperature and Ion Energy in Two Different Magnetic Nozzle Thruster Designs Open
Conventional ion thruster technologies face challenges such as electrode and grid erosion and the need for additional neutralizer devices. In this article, we discuss two thruster concepts that achieve plasma acceleration by means of a mag…
View article: Modeling of polyatomic gases in the kinetic Fokker-Planck method by extension of the master equation approach
Modeling of polyatomic gases in the kinetic Fokker-Planck method by extension of the master equation approach Open
An extension of the Fokker-Planck method for polytatomic gas using the master equation approach is presented. The model is compatible with different Fokker-Planck formulations. An example using the cubic formulation is provided. Code-to-co…
View article: Contamination assessment of a freely expanding green propellant thruster plume
Contamination assessment of a freely expanding green propellant thruster plume Open
A number of propellant/thruster combinations are under development in recent years that aim to replace the prevailing hydrazine-driven reaction control thrusters with less hazardous substances (“green propellants”). With some of these syst…
View article: Monopropellant plume-induced contamination testing for the Europa Lander mission concept
Monopropellant plume-induced contamination testing for the Europa Lander mission concept Open
The induced contamination from two hydrazine-propelled thrusters is studied in the high-vacuum plume test facility for chemical thrusters at DLR Göttingen, STG-CT. A number of representative material samples are exposed to the freely expan…
View article: A kinetic Fokker–Planck approach for modeling variable hard-sphere gas mixtures
A kinetic Fokker–Planck approach for modeling variable hard-sphere gas mixtures Open
Kinetic Fokker–Planck (FP) methods for modeling rarefied gas flows have received increasing attention over the last few years. However, formulating such models for realistic multi-species gases is still an open subject of research. Therefo…
View article: A kinetic Fokker–Planck approach to model hard-sphere gas mixtures
A kinetic Fokker–Planck approach to model hard-sphere gas mixtures Open
Since its first introduction, it has always been a subject of research to find models for a meaningful approximation of the highly accurate but complex Boltzmann equation. In the kinetic Fokker–Planck (FP) approach, a FP operator in veloci…
View article: Status and Future of Research on Plume Induced Contamination
Status and Future of Research on Plume Induced Contamination Open
Spacecraft typically rely on chemical propulsion systems for active attitude and orbit control during cruise stage, and for entry, descent and landing on planetary surfaces. In addition to thruster performance parameters, spacecraft and mi…
View article: STG-CT: High-vacuum plume test facility for chemical thrusters
STG-CT: High-vacuum plume test facility for chemical thrusters Open
The STG-CT, operated by the DLR Institute for Aerodynamics and Flow Technology in Göttingen, is a vacuum facility specically designed to provide and maintain a space-like vacuum environment for researching plume flow and plume impingement …