Characterization of Lunar Regolith Pyrolysis Using Concentrated Solar Energy

The CNRS PROMES laboratory is applying for CNES PhD funding on the topic: Characterization of Lunar Regolith Pyrolysis Using Concentrated Solar Energy

A first PhD project (2023–2026) was initiated at CNRS-PROMES thanks to ESA and CNES (Spaceship project) support in order to quantify oxygen production from lunar regolith by using concentrated solar energy. CNRS-PROMES (Processes, Materials and Solar Energy) is a laboratory especially dedicated to high temperature materials and concentrated solar energy with unique solar concentrators able to reach pyrolysis temperature of regolith (>1800°C). It has a strong background in solar thermochemical reactor design and operation. A state-of-the-art review on the lunar regolith pyrolysis has been published [1] by CNRS-PROMES. While previous experiments had already shown that oxygen could be extracted from lunar dust, no quantitative assessment had been carried out due to various experimental limitations. In the meantime, ESA published a thermodynamic study and very first experimental trials showing that regolith could be decomposed by high temperature solar heat [2].

In the ongoing PhD work, a novel solar pyrolyser has been set-up and instrumented (mass spectrometer, online oxygen analyser, primary pump, pyrometer and pressure sensors) and for the first time, oxygen production has been quantified: 1 wt% of lunar regolith was recovered as oxygen at temperatures around 2000 °C and pressures of about 10 mbar. This first quantification was already partly shared at the SOLARPACES 2024 conference [3]. Although this result represents a significant breakthrough, it now appears possible to go deeper into the characterization of lunar regolith pyrolysis producing both reduced species and oxygen by using concentrated solar energy.

The scientific objectives of the new PhD project are multiple and aim to provide a better understanding of the thermal, hydrodynamic, and chemical pyrolysis mechanisms in order to better characterize and optimize the solar process. Specifically, the work will focus on:

• Optimizing heat transfer and minimizing thermal losses to ensure the most efficient use of solar energy and thus increase pyrolysis efficiency. This will notably involve using a cavity-type reactor to approach isothermal conditions.
• Modeling the hydrodynamic mechanisms of pyrolysis vapor flow in order to control quenching and condensation zones (which could be selective) of vaporized reduced species. Improved hydrodynamic control could also help to better manage the recombination of oxygen with reduced species in the gas phase (prior to condensation).
• Advancing the solar reactor design for operation at lower pressures (possible on the Moon) to facilitate the reaction and improve regolith conversion (new reactor design with secondary pumping). Operating without argon dilution would represent another step toward a proof of concept applicable on the Moon. Various regolith simulants along with pure oxides will be compared. Regolith samples from NASA or lunar meteorites are also targeted in order to produce reference data.
• In depth characterization of condensed species (XRD, XRF, Raman spectroscopy, SEM-EDX analysis). This will make it possible to assess whether metallic species can be valorized in addition to gaseous oxygen. First experimental results showed the presence of ferromagnetic species in deposits meaning that iron oxides could be recovered.
• Proposing a reaction scheme and determining reaction kinetics to better understand the stages of the pyrolysis process.
• Developing a lunar process that integrates the different stages (system design, dynamic reactor simulation, and solar concentrator sizing) in order to refine the design of a proof-of-concept demonstrator deployed on the Moon.

The objective is to publish at least three open access articles in international journals and to participate at least in two international conferences (Solar Power and Chemical Energy Systems Conference, Space Resources Conference, Space Resources Week, International Astronautical Congress). This will go along with project reporting, data sharing and scientific mediation.

[1] Robinot, J., Rodat, S., Abanades, S., Paillet, A., & Cowley, A. (2025). Review of in-situ oxygen extraction from lunar regolith with focus on solar thermal and laser vacuum pyrolysis. Acta Astronautica.

[2] Lamboley, K., Cutard, T., Grill, L., Reiss, P., & Cowley, A. (2024). Oxygen production by solar vapor-phase pyrolysis of lunar regolith simulant. Acta Astronautica.

[3] Jack Robinot, Sylvain Rodat, Stéphane Abanades, Alexis Paillet, Aidan Cowley. Concentrated solar pyrolysis of lunar regolith for oxygen extraction. SOLARPACES 2024, Oct 2024, Rome, Italy

The PROMES laboratory is a CNRS Proprietary Unit (UPR 8521) attached to the Institute of Engineering and Systems Sciences (INSIS), under agreement with the University of Perpignan via Domitia (UPVD). The laboratory is located on three sites: Odeillo-Font Romeu (1 MW solar furnace of the CNRS), Targasonne (Thémis, 5 MW tower power plant, site of the Conseil Départemental des PO) and Perpignan, Tecnosud.

Skills

The candidate (Master2 or Engineer) must have a strong background in materials, processes and energy engineering (materials science and characterization, chemical reactors, thermochemistry, kinetics, mass/energy balances). An interest in both experimental and modeling work is required, as well as a good command of scientific English (writing reports and articles in English).