Air-breathing electric propulsion: mission characterization and design analysis

Crandall, Patrick; Wirz, Richard E.

doi:10.1007/s44205-022-00009-8

Cited by 8 publications

(2 citation statements)

References 24 publications

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“…Indeed, when a satellite passes over, it becomes visible and there exists a strong LoS component. Additionally, the distances and velocities of the satellites comply with the records in [43], [44]. On the other hand, since the most important variables are the transmit power P , as wel as the number of antennas L, and the number of RIS elements N , we will mainly provide numerical results versus these variables.…”

Section: Numerical Resultsmentioning

confidence: 99%

Secrecy-Rate Optimization of Double RIS-Aided Space–Ground Networks

Hoang

Vahid

et al. 2023

IEEE Internet Things J.

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The physical layer security (PLS) of a space-ground communication system is examined. To improve the security performance, a pair of reconfigurable intelligent surfaces (RISs) is integrated into the system and benchmarked against a scheme, where there is only a single RIS close to the ground station. As for the double-RIS scenario, we formulate a secrecy rate maximization problem, and then propose an alternating optimization (AO) algorithm for jointly optimizing three vectors, namely the beamformer of the ground station and the reflecting vectors of two different RISs. Similarly, as for the single-RIS case, we also propose another AO algorithm for optimizing a pair of vectors, namely the beamformer of the ground station and the reflecting vector of the single RIS. Both the double-RIS and the single-RIS AO algorithms are developed on the basis of the first-order Taylor expansion and the Dinkelbach's method, which allow us to approximate non-convex optimization problems by convex ones. Our results demonstrate that the proposed double-RIS scheme outperforms the single-RIS benchmark scheme in terms of its security.

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Section: Numerical Resultsmentioning

confidence: 99%

Secrecy-Rate Optimization of Double RIS-Aided Space–Ground Networks

Hoang

Vahid

et al. 2023

IEEE Internet Things J.

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“…Several recent mission analysis studies of the ABEP scenario conclude that high specific impulse (I sp ) is a key desired characteristic of the thruster, with a minimum I sp requirement of at least around 3000 s [1,2,5]. This is driven primarily by the tangential drag of the spacecraft and solar array surfaces, which is significant even if these surfaces are aligned with the VLEO air flow.…”

Section: Introductionmentioning

confidence: 99%

Influence of applied magnetic field in an air-breathing microwave plasma cathode

Tisaev,

Karadag,

Fabris

2023

J. Phys. D: Appl. Phys.

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The air-breathing electric propulsion (ABEP) concept refers to a spacecraft in very-low Earth orbit (VLEO) ingesting upper atmospheric air as propellant for an electric thruster. This compensates atmospheric drag and allows the spacecraft to maintain its orbital altitude, removing the need for on-board propellant storage and allowing an extended mission duration which is not limited by propellant exhaustion. There is a need for development of a robust, high current density and long life cathode (or neutralizer) for air-breathing electrostatic thrusters as conventional thermionic hollow cathodes are susceptible to oxygen poisoning. An Air-breathing Microwave Plasma CAThode (AMPCAT) is proposed to overcome this issue through the use of a microwave plasma discharge, producing an extracted current in the order of 1 A with 0.1 mg/s of air. In this paper, the effect of varying magnetic-field strength and topology is investigated by using an electromagnet coil, which reveals a significantly different behaviour for air compared to xenon. The extracted current with xenon increases by 3.9 times from the zero-field value up to a peak around 150 mT magnetic-field strength at the antenna, whereas an applied field does not increase the extracted current with air at nominal conditions. A non-zero magnetic-field with air is however beneficial for current extraction at reduced neutral densities. A distinct increase in extracted current is identified at low bias voltages with air for a field strength of around 50 mT at the internal microwave antenna, consistent across varying field topologies. The effect of a lowered magnetic-field strength in the orifice region is investigated through the use of a secondary coil, resulting in an extracted current increase of 25 % for a relaxation from 6 mT to 1 mT, and demonstrating the beneficial impact of a locally reduced field strength on electron extraction.

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A review of air-breathing electric propulsion: from mission studies to technology verification

2022

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Air-breathing electric propulsion (ABEP) allows for lowering the altitude of spacecraft operations below 250 km, in the so-called Very Low Earth Orbits (VLEOs). Operations in VLEOs will give radical advantages in terms of orbit accessibility, payload performance, protection from radiations, and end-of-life disposal. ABEP combines an intake to collect the residual atmosphere in front of the spacecraft and an electric thruster to ionize and accelerate the atmospheric particles. Such residual gas can be exploited as a renewable resource not only to keep the spacecraft on a VLEO, but also to remove the main limiting factor of spacecraft lifetime, i.e., the amount of stored propellant. Several realizations of the ABEP concept have been proposed, but the few end-to-end experimental campaigns highlighted the need to improve the concept functional design and the representativeness of simulated atmospheric flows. The difficulty in recreating the VLEO environment in a laboratory limits the data available to validate scaling laws and modelling efforts. This paper presents a comprehensive review of the main research and development efforts on the ABEP technology.

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Air-breathing electric propulsion: mission characterization and design analysis

Cited by 8 publications

References 24 publications

Secrecy-Rate Optimization of Double RIS-Aided Space–Ground Networks

Secrecy-Rate Optimization of Double RIS-Aided Space–Ground Networks

Influence of applied magnetic field in an air-breathing microwave plasma cathode

A review of air-breathing electric propulsion: from mission studies to technology verification

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