Caroline O'Connell
Academic and research departments
Surrey Space Centre, Lunar Construction and In-Situ Resource Utilisation Group.About
My research project
To improve the heating of lunar regolith simulants with microwave energy by utilising the dielectric properties of regolith as a function of temperature.To establish a permanent human presence on the moon, we need to build infrastructure using lunar resources that are readily available and sustainable and to use these efficiently. Processing lunar regolith using microwave energy is an efficient means of building components such as landing pads, roads and bricks, as well as more complex construction components using 3D printing techniques. Microwave heating efficiency is determined by the dielectric properties of the material being heated. Research has shown that the dielectric constant and dielectric loss of lunar regolith change with temperature. The objective of this research is to measure the dielectric properties of lunar regolith simulants as a function of temperature up to melting point, and to improve the accuracy of current Multiphysics simulations of the heating of lunar regolith simulants by using temperature-dependent measurements. This will lead to more efficient processing of lunar regolith using microwave energy.
Supervisors
To establish a permanent human presence on the moon, we need to build infrastructure using lunar resources that are readily available and sustainable and to use these efficiently. Processing lunar regolith using microwave energy is an efficient means of building components such as landing pads, roads and bricks, as well as more complex construction components using 3D printing techniques. Microwave heating efficiency is determined by the dielectric properties of the material being heated. Research has shown that the dielectric constant and dielectric loss of lunar regolith change with temperature. The objective of this research is to measure the dielectric properties of lunar regolith simulants as a function of temperature up to melting point, and to improve the accuracy of current Multiphysics simulations of the heating of lunar regolith simulants by using temperature-dependent measurements. This will lead to more efficient processing of lunar regolith using microwave energy.
Publications
To establish a permanent settlement on the Moon, infrastructure will need to be built to protect humans fromradiation, temperature extremes and meteorite impact, and protect equipment such as solar panels, instrumentsand rovers from abrasive lunar dust. Lunar regolith, the layer of loose, unconsolidated rocks and fine-grainedparticles covering the surface of the Moon, is a dielectric material which can be efficiently heated to meltingtemperature using microwave energy [1]. Sintered or melted regolith can then be used as feedstock to constructlanding pads, roadways and habitats, as well as more complex components using additive manufacturing.Measurements of permittivity in lunar regolith simulants, up to their melting temperature, are crucial forenhancing computational models and increasing the accuracy of numerical simulations related to themicrowave heating process. This will facilitate improved modelling for the design and optimisation of regolithmelting using microwave heating.In this study, Microwave Dielectric Thermal Analysis (MW-DETA) [2] was employed for the first time tomeasure the complex permittivity of lunar regolith simulants at temperatures of up to 1200 oC. The dual-modetechnique enables the simultaneous measurement of real and imaginary permittivity while the sample is heatedusing 150W microwave power close to 2.43 GHz.
Lunar regolith is a dielectric material which can be efficiently heated to melting temperature using microwave energy [1]. Sintered or melted regolith can then be used as feedstock to construct infrastructure on the Moon, including landing pads, roadways and habitats. A material’s real permittivity, ε’, and imaginary permittivity, ε’’, are important factors in determining the efficiency of microwave heating. For lunar regolith, these increase with temperature [2,3].Temperature-dependent permittivity measurements made under microwave heating [3] have been found to differ notably from those made under furnace heating [2]. This suggests that the heating method influences permittivity measurements. Therefore, understanding the underlying mechanisms behind this behaviour will enable improved computational modelling and the optimisation of microwave heating processes.
Microwave processing of lunar regolith presents a promising approach for in-situ construction on the Moon, reducing the need for terrestrial material transport. This study investigates the dielectric behavior of a lunar reg-olith simulant as a function of temperature, with particular focus on its suitabil-ity for microwave-induced melting. Results show a significant increase in both dielectric constant and loss factor with temperature, especially beyond the glass transition (~650 °C) and melting point (~990 °C), where molecular and ionic mobility markedly enhance microwave absorption. These findings suggest a self-reinforcing heating effect that can improve energy efficiency and process speed. This knowledge has important implications for the design of microwave reactors capable of operating under lunar conditions, offering a potential solution for sustainable, on-site fabrication of structural materials for extraterrestrial habitats.
Lunar regolith is a dielectric material which can be efficiently heated to melting temperature using microwave energy [1]. Sintered or melted regolith can then be used as feedstock to construct infrastructure on the Moon, including landing pads, roadways and habitats. Additionally, it can be used to produce more complex components using additive manufacturing.A material’s permittivity, (with the real part or dielectric constant ε’, and imaginary part or loss factor, ε’’), is the factor governing the behaviour of materials under electromagnetic fields, and thus, determining the efficiency of microwave heating. For lunar regolith, permittivity increases with temperature [2].Temperature-dependent measurements of permittivity in lunar regolith simulants, up to their melting temperature, are crucial for enhancing computational models and increasing the accuracy of numerical simulations related to the microwave heating process. This will facilitate improved modelling for the design and optimisation of regolith melting using microwave heating.