Periodic Reporting for period 1 - MaRe-HCT (Magnetic Reconnection Hollow Cathode Thruster)
Période du rapport: 2023-03-01 au 2025-06-30
The 21st Century signed a new era of the space race, with potential groundbreaking perspectives in the outer space missions. Commercial low-Earth orbit constellations for global connectivity, the Cislunar space station and the potential return of mankind on the moon, and robotic exploration of the regions of the solar system never reached before are just a few examples of the opportunities that emerge from the so-called New Space Economy. However, this new space race has also brought its unique set of challenges. Rapid astronauts’ transport and cargo re-supply to establish the infrastructure for long-term human presence on the moon and to enable human exploration of Mars have accentuated the need for adequate in-space propulsion systems. In fact, the total delta-V (i.e. the energetic requirements) necessary to complete today’s and tomorrow’s space missions is becoming more and more demanding.
In this context, the propulsion system is required to provide this large amount of delta-V with the lowest propellant consumption.
MaRe-HCT offers an innovative and potentially groundbreaking solution for these challenges: a novel electric propulsion concept based on magnetic reconnection as main acceleration mechanism.
The main goal of MaRe-HCT was the investigation of magnetic reconnection as main acceleration source in an innovative plasma propulsion technology. Magnetic reconnection is the process whereby magnetic field lines break and then reconnect to form a different topology. In general, it allows the conversion of stored magnetic energy into the particles’ kinetic energy, which results in a significantly more effective acceleration of the present particles than in the classical case. This project investigated the development of a novel plasma propulsion concept which relies on hollow cathodes as plasma source, and on magnetic reconnection as acceleration mechanism.
Three main objectives have been depicted:
❖ Objective 1: Investigation of magnetic reconnection phenomena in the plasma generated by a high current hollow cathode.
❖ Objective 2: Identification of the main parameters to control the instabilities and the magnetic reconnection phenomena.
❖ Objective 3: Develop and test a proof-of-concept of the magnetic reconnection thruster to achieve Technology Readiness Level (TRL) 4 for the proposed solution.
In this context, the propulsion system is required to provide this large amount of delta-V with the lowest propellant consumption.
MaRe-HCT offers an innovative and potentially groundbreaking solution for these challenges: a novel electric propulsion concept based on magnetic reconnection as main acceleration mechanism.
The main goal of MaRe-HCT was the investigation of magnetic reconnection as main acceleration source in an innovative plasma propulsion technology. Magnetic reconnection is the process whereby magnetic field lines break and then reconnect to form a different topology. In general, it allows the conversion of stored magnetic energy into the particles’ kinetic energy, which results in a significantly more effective acceleration of the present particles than in the classical case. This project investigated the development of a novel plasma propulsion concept which relies on hollow cathodes as plasma source, and on magnetic reconnection as acceleration mechanism.
Three main objectives have been depicted:
❖ Objective 1: Investigation of magnetic reconnection phenomena in the plasma generated by a high current hollow cathode.
❖ Objective 2: Identification of the main parameters to control the instabilities and the magnetic reconnection phenomena.
❖ Objective 3: Develop and test a proof-of-concept of the magnetic reconnection thruster to achieve Technology Readiness Level (TRL) 4 for the proposed solution.
In order to achieve the objectives declared, multiple activities have been peformed, including experimental test campaigns, data analysis, theoretical analysis, and design of the thruster configuration.
At first, all the activities necessary to perform magnetic reconnection (MR) tests on the MaRe-HCT simulator, grouped into three broad parts, have been performed:
1. Manufacture the thruster simulator, design and constructing the required intrusive probes, and setup non-intrusive diagnostics such as OES.
2. Intrusive diagnostics measurements collected from the simulator: steady-state and time variable plasma parameters to evaluate the electrostatic and magnetic properties.
3. Non-intrusive diagnostic test.
Then, all the data collected during the experimental campaigns have been analyzed. Standard data analysis techniques are adopted for the Hall probe, and foreseen for the upcoming test with the emissive probes. Advanced data analysis including POD, wavelet transformation, Bayesian data fusion, were implemented to study the high-speed camera videos. In addition, advanced techniques were adopted to investigate in parallel previous data obtained with Langmuir probes and RPA, all to extend these techniques to the MR thruster test campaigns.
The next step included a theoretical investigation of the thruster. Different approaches have been evaluated, with the aim of reducing the complexity of the analysis. Specifically, reduced order (0D scaling, 1D) models of the magnetic reconnection thruster were considered to obtain the thruster parameters such as thrust and specific impulse.
A 0D model, based on the MHD equations and on the characteristics of the new MR thruster model has been developed, with which it was possible to predict the specific impulse of the thruster.
Finally, the engineering proof-of-concept has been designed.
At first, all the activities necessary to perform magnetic reconnection (MR) tests on the MaRe-HCT simulator, grouped into three broad parts, have been performed:
1. Manufacture the thruster simulator, design and constructing the required intrusive probes, and setup non-intrusive diagnostics such as OES.
2. Intrusive diagnostics measurements collected from the simulator: steady-state and time variable plasma parameters to evaluate the electrostatic and magnetic properties.
3. Non-intrusive diagnostic test.
Then, all the data collected during the experimental campaigns have been analyzed. Standard data analysis techniques are adopted for the Hall probe, and foreseen for the upcoming test with the emissive probes. Advanced data analysis including POD, wavelet transformation, Bayesian data fusion, were implemented to study the high-speed camera videos. In addition, advanced techniques were adopted to investigate in parallel previous data obtained with Langmuir probes and RPA, all to extend these techniques to the MR thruster test campaigns.
The next step included a theoretical investigation of the thruster. Different approaches have been evaluated, with the aim of reducing the complexity of the analysis. Specifically, reduced order (0D scaling, 1D) models of the magnetic reconnection thruster were considered to obtain the thruster parameters such as thrust and specific impulse.
A 0D model, based on the MHD equations and on the characteristics of the new MR thruster model has been developed, with which it was possible to predict the specific impulse of the thruster.
Finally, the engineering proof-of-concept has been designed.
During the course of the project, I investigated and further improved a concept of magnetic reconnection thruster that could be used also at relatively low discharge power and available for the next gneration space missions. This concept has raised interest in the space propulsion and plasma physics communities, and it is currently continuing with further research and additional experimental campaings.