A hollow cathode produces electrons which neutralize ions from electric propulsion thrusters. After hundreds to thousands of hours of operation in space, the cathode materials can be significantly eroded due to ion bombardment. As a result, the electric propulsion system performance will be obviously changed or even fail. In this work, the erosion products from a LaB hollow cathode (widely used presently in electric propulsion systems) are studied by using a specific detection system, which consists of a molecular beam sampler and a time-of-flight mass spectrometer. This system measures trace-level-concentration (10-10) products. Boron (B), tantalum (Ta), and tungsten (W)-originating from the emitter, keeper, and orifice of the hollow cathode-are measured. It is found that the erosion rate is significantly influenced by the gas flow rate to the cathode.
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December 2024
Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology (BIST), Av. Països Catalans, 16, Tarragona, E-43007, Spain.
Micro/nanomotors (MNMs) are highly versatile small-scale devices capable of converting external energy inputs into active motion. Among the various energy sources, light stands out due to its abundance and ability to provide spatiotemporal control. However, the effectiveness of light-driven motion in complex environments, such as biological tissues or turbid water, is often limited by light scattering and reduced penetration.
View Article and Find Full Text PDFDiscov Nano
December 2024
IMDEA Materials Institute, C/Eric Kandel 2, 28906, Getafe, Madrid, Spain.
New materials for electrical conductors, energy storage, thermal management, and structural elements are required for increased electrification and non-fossil fuel use in transport. Appropriately assembled as macrostructures, nanomaterials can fill these gaps. Here, we critically review the materials science challenges to bridge the scale between the nanomaterials and the large-area components required for applications.
View Article and Find Full Text PDFJ Elect Propuls
July 2024
RMC Advanced Propulsion and Plasma Exploration Laboratory (RAPPEL), Department of Mechanical and Aerospace Engineering, Royal Military College of Canada, 13 General Crerar Crescent, Kingston, K7K 7B4 Ontario Canada.
Electrospray thrusters are a promising electric micropropulsion technology which could be used to meet the propulsion needs of nanosatellites, or for fine attitude control of larger spacecraft. Multimodal propulsion is the integration of two or more propulsion modes into a system which utilizes a common propellant. Indeed, spacecraft mission simulations and models have shown that this type of multimode propulsion capacity is exciting because of the flexibility and adaptability it provides mission designers and planners.
View Article and Find Full Text PDFJ Elect Propuls
December 2024
School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA 30332 USA.
Hall effect thrusters (HETs) are typically regarded as DC electric propulsion devices as they are operated with isolated DC power supplies. However, it is well known that the HET's discharge current possesses oscillations of varying magnitudes and frequencies and is thus a function of time with AC characteristics. The observed oscillations are caused by plasma processes associated with ion, electron, and neutral particle dynamics that occur inside the HET's discharge channel and in the plume as the HET electrically interacts with its local operating environment.
View Article and Find Full Text PDFAdv Sci (Weinh)
December 2024
Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA, 70803, USA.
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