UNDERSTANDING LUNAR VOLCANIC PROCESSES AND MARE SURFACE AGE-DATING VIA REMOTE SENSING

Ph.D

A miniaturized 3d heat flux sensor to characterize heat transfer in regolith of planets and small bodies

The objective of this work is to present the first analytical and experimental results obtained with a 3D heat flux sensor for planetary regolith. The proposed structure, a sphere divided in four sectors, is sensible to heat flow magnitude and angle. Each sector includes a platinum resistor that is used both to sense its temperature and provide heating power. By operating the sectors at constant temperature, the sensor gives a response that is proportional to the heat flux vector in the regolith. The response of the sensor is therefore independent of the thermal conductivity of the regolith. A complete analytical solution of the response of the sensor is presented. The sensor may be used to provide information on the instantaneous local thermal environment surrounding a lander in planetary exploration or in small bodies like asteroids. To the best knowledge of the authors, this is the first sensor capable of measuring local 3D heat fluxThis work was supported in part by the Spanish Ministerio de Economía y Competividad under Projects RTI2018-098728-B-C31 and RTI2018-098728-B-C33Peer ReviewedPostprint (published version

Interpretations of Lava Flow Properties from Radar Remote Sensing Data

The surface morphology and roughness of a lava flow provides insight on its lava properties and emplacement processes. This is essential information for understanding the eruption history of lava fields, and magmatic processes beneath the surface of Earth and other planetary bodies such as the Moon. The surface morphology is influenced by lava properties such as viscosity, temperature, composition, and rate of shear. In this work, we seek to understand how we can interpret the emplacement processes and lava properties of lava flows using remote sensing data. Craters of the Moon (COTM) National Monument and Preserve in Idaho hosts a suite of compositionally diverse lava flows with a wide range of surface roughness making it the ideal case study. Lava flows there have surface morphologies consistent with smooth pāhoehoe, slabby pāhoehoe, hummocky pāhoehoe, rubbly pāhoehoe, ‘a’ā, block-`a’ā, and blocky textures. The variation in surface roughness across the lava field reflects changes in lava properties and/or emplacement processes over space and time. We investigate geochemical and petrographic variations of the different lava flow morphologies and analyse how they relate to airborne radar data. Results show L-Band (24 cm) radar circular polarization ratios (CPR) distinguish the contrasting surface roughness at COTM, separating the smoother (primitive; low SiO2 and alkali) and rougher (evolved; high SiO2 and alkali) lava flows. However, ambiguities are present when comparing the CPR values for rubbly pāhoehoe and block-`a’ā flow. Even though their CPR values appear similar at the decimetre scale, they have distinct morphologies that formed under different emplacement processes. Without ground-truth information, the rubbly pāhoehoe and block-`a’ā lava flows could therefore be misinterpreted to be the same type of flow morphology, which would lead to false interpretations about their lava properties and emplacement processes. This is important when comparing these flows to lava flows on other planetary bodies that share similar CPR values, such as the Moon. Thus, using terrestrial analogues such as those at COTM can provide an improved understanding of the surface morphology and emplacement processes of lunar lava flows. This will lead to more refined interpretations about past volcanic processes on the Moon

Lunar Reconnaissance Orbiter Science Targeting Meeting : Arizona State University, Tempe, Arizona, June 9-11, 2009

A key goal of this meeting was to foster understanding of LRO capabilities and the mission planning processes necessary for high-resolution targeting of lunar features by the LRO Narrow Angle Cameras (NAC), Mini-RF synthetic aperture radar, and Diviner Lunar Radiometer Experiment. Another goal was to solicit ideas from the lunar science community for LRO targeting of specific types of features and focused science themes.conveners : Steve Mackwell ... [and others] ; organizing committee: Mark Robinson ... [and others]The Lunar Regolith as a Remote Sensing Target for the Lunar Reconnaissance Orbiter (LRO)--Lunar Volcanism: Timing, Form, and Composition--Lunar Crustal Rock Types, Global Distribution, and Targeting--Lunar Resources and LRO--Targeting Complex Craters and Multi-Ring Basins to Determine the Tempo of Impact Bombardment While Simultaneously Probing the Lunar Interior--Current Understanding of Lunar Volatile Transport and Segregation

Terrestrial Demonstrator for the Hydrogen Extraction of Oxygen from Lunar Regolith with Concentrated Solar Energy

An experimental plant for the reduction of granular ilmenite (FeTiO3) with hydrogen (H2) powered by concentrated solar radiation was designed, built, and tested to demonstrate extraction of oxygen from lunar soil at the Plataforma Solar de Almería (PSA). This is done by a two-step process with water (H2O) as the intermediate product. The center-piece of the system is a fluidized bed reactor with a capacity of 22 kg of ilmenite, capable of operating in fully continuous mode. The reactor has a large quartz window that allows the concentrated solar radiation to heat the particles directly without the need for any heat exchanger surfaces. The system includes most of the peripheral components required to demonstrate its functioning as close as possible to what can be expected on the Moon. This includes in particular the cleaning system for the off-gas from the reactor, the extraction of the product water, and the gas recovery. The system was operated in the 60 kW Solar Furnace at PSA with solar power during 150 hours in four test campaigns. All initial test goals were successfully achieved. The maximum operation temperature in the reactor was 977 °C, and during a total of 21 hours of operation with hydrogen, the chemical reaction produced more than 1300 ml of water. To this date, this is the only large scale terrestrial demonstrator in Europe that has successfully produced water from minerals present in lunar regolith solely with concentrated solar power as heat source, showing a path for future chemical production on the lunar surface.En la Plataforma Solar de Almería (PSA) se ha diseñado, construido y probado una planta experimental para la reducción de ilmenita granular (FeTiO3) con hidrógeno (H2), alimentada por radiación solar concentrada con el objetivo de demostrar la extracción de oxígeno de la roca lunar. Esto se hace mediante un proceso de dos pasos con agua (H2O) como producto intermedio. La pieza central del sistema es un reactor tipo lecho fluidizado con una capacidad de 22 kg de ilmenita, capaz de funcionar completamente en modo continuo. El reactor tiene una gran ventana de cuarzo que permite que el rayo solar concentrado caliente directamente las partículas sin necesidad de ninguna superficie de intercambio de calor. El sistema incluye la mayoría de los componentes periféricos necesarios para demostrar su funcionamiento lo más parecido posible a lo que se puede esperar en la Luna. Esto incluye, en particular, el sistema de limpieza del gas de salida del reactor, la extracción del agua producto, y la recirculación del gas. El sistema fue operado en el Horno Solar de 60 kW en la PSA con energía solar durante 150 horas en cuatro campañas de ensayo. Todos los objetivos iniciales se alcanzaron con éxito. La temperatura máxima en el reactor fue de 977 °C, y durante un total de 21 horas de operación con hidrógeno, la reacción química produjo más de 1300 ml de agua. Hasta la fecha, este es el único demostrador terrestre a gran escala en Europa que ha producido con éxito agua a partir de minerales presentes en el regolito lunar únicamente con energía solar concentrada como fuente de calor, mostrando un camino para una futura producción química en la superficie lunar.Auf der Plataforma Solar de Almería (PSA) wurde eine mit konzentrierter Solarstrahlung betriebene Versuchsanlage zur Reduktion von granularem Ilmenit (FeTiO3) mit Wasserstoff (H2) entworfen, gebaut und getestet, um die Gewinnung von Sauerstoff aus Mondgestein zu demonstrieren. Dies geschieht in einem zweistufigen Prozess mit Wasser (H2O) als Zwischenprodukt. Das Herzstück des Systems ist ein Wirbelschichtreaktor mit einem Fassungsvermögen von 22 kg Ilmenit, der vollständig im kontinuierlichen Modus betrieben werden kann. Der Reaktor verfügt über ein großes Quarzfenster, durch das die konzentrierte Solarstrahlung die Partikel direkt erwärmen kann, ohne dass irgendwelche Wärmetauscher-flächen erforderlich wären. Das System umfasst die meisten peripheren Komponenten, die notwendig sind, um seine Funktionsweise so nah wie möglich an dem zu demonstrieren, was auf dem Mond zu erwarten ist. Dazu gehören insbesondere das Reinigungssystem für das Gas aus dem Reaktor, die Extraktion des Produktwassers sowie die Gasrückführung. Das System wurde im 60 kW-Sonnenofen der PSA in vier Testkampagnen für 150 Stunden mit Solarenergie betrieben. Alle anfänglichen Testziele wurden erfolgreich erreicht. Die maximale Betriebs-temperatur im Reaktor betrug 977 °C, und während des insgesamt 21-stündigen Betriebs mit Wasserstoff wurden durch die chemische Reaktion mehr als 1300 ml Wasser erzeugt. Bis heute ist dies der einzige in größerem Maßstab gebaute terrestrische Demonstrator in Europa, der erfolgreich Wasser aus den im Mondregolith vorhandenen Mineralen ausschließlich mit konzentrierter Solarenergie als Wärmequelle hergestellt hat, was einen Weg für zukünftige chemische Produktion auf der Mondoberfläche aufzeigt.Une installation expérimentale pour la réduction de l'ilménite granulaire (FeTiO3) avec de l'hydrogène (H2), alimentée par le rayonnement solaire concentré, a été conçue, construite et testée à la Plataforma Solar de Almería (PSA) pour démontrer l'extraction de l'oxygène du sable lunaire. Ce processus se déroule en deux étapes, l'eau (H2O) étant un produit intermédiaire. La pièce centrale du système est un réacteur à lit fluidisé d'une capacité de 22 kg d'ilménite, capable de fonctionner entièrement en continu. Le réacteur est doté d'une grande fenêtre en quartz qui permet au rayon solaire concentré de chauffer directement les particules sans qu'aucune surface d'échange thermique ne soit nécessaire. Le système comprend la plupart des composants périphériques nécessaires à une démonstration de son fonctionnement le plus proche possible de ce qui peut être envisagé sur la Lune. Il s'agit notamment du système d'épuration du gaz d'échappement du réacteur, de l'extraction de l'eau du produit et de la recirculation du gaz. Le système a fonctionné dans le four solaire de 60 kW de la PSA avec de l'énergie solaire pendant 150 heures au cours de quatre campagnes d'essai. Tous les objectifs initiaux ont été atteints avec succès. La température maximale de fonctionnement dans le réacteur était de 977 °C, et pendant un total de 21 heures de fonctionnement avec de l'hydrogène, la réaction chimique a produit plus de 1300 ml d'eau. À ce jour, il s'agit du seul démonstrateur terrestre à grande échelle en Europe qui a réussi à produire de l'eau à partir de minéraux présents dans le régolithe lunaire en utilisant uniquement l'énergie solaire concentrée comme source de chaleur, montrant ainsi une voie à suivre pour la production chimique future sur la surface lunaire

Modelling the survival of meteoritic material exchanged between planetary bodies: scientific and commercial implications

Impacts are the most ubiquitous process across the Solar System, with every solid planetary surface we see marked by evidence of this process in some regard. Some impacts provide enough energy for the transfer of material between planetary bodies. Using the iSALE shock physics code, the survival of projectile material after impact with the Moon is investigated. The work within this thesis also explores the transfer of ejecta from Earth to the Moon, as well as investigating the survival of a particular set of larger asteroids (carbonaceous chondrites) that impact the lunar surface. This thesis investigates the potential for terrestrial material (i.e., terrestrial meteorites) to be transferred to the Moon by a large impact on Earth and subsequently survive impact with the lunar surface. Three-dimensional impact simulations show that a typical basin-forming impact on Earth can eject solid fragments at speeds sufficient to transfer them from Earth to the Moon. The importance of considering temperature when assessing the survival of biomarkers within the projectile is shown with the inclusion of a strength model that can resolve both shock and shear heating. This work shows that, assuming survival after launch from Earth, some biomarker molecules within terrestrial meteorites are likely to survive impact with the Moon, especially at the lower end of the range of typical impact velocities for terrestrial meteorites (2.5 km s−1). Long-term survival of biomarkers depends heavily upon where the projectile material lands, whether it is buried or remains on the surface, and the related cooling timescales. Carbonaceous chondrites contain relatively large quantities of carbon and nitrogen, two elements that are particularly depleted in the lunar crust. This work assesses the viability of surviving carbon and nitrogen within the impacted asteroids at a range of impact angles and velocities. At impact velocities of 5 km s−1, up to 86% of the impactor remains solid with the potential to retain carbon- and nitrogen-based compounds. Highly oblique impacts (15°) lead to material concentrating out of the crater rim, downrange in the direction of impact. Increasing impact velocity and angle decreases the proportion of surviving solid material. However, less oblique impacts concentrate surviving material within or close to the crater rim, which may be beneficial for resource utilisation

The Physical Properties of Volcanic and Impact Melt

The emplacement mechanisms of lunar impact melt flows, that form from hypervelocity impact events, have been a subject of debate in the lunar science community, because of their unique physical properties that separate them from other geologic features. Understanding how lunar impact melt flows were emplaced on the surface of the Moon will not only grant us new information about the flow dynamics of impact melt but provide insight into the production and distribution of impact melt and how it built and modified the surfaces of planetary surfaces. Lunar impact melt flows exhibit surface roughness textures and morphologies that are analogous to terrestrial lava flows. For this reason, we seek to quantify the surface roughness of terrestrial lava flows using synthetic aperture radar (SAR) at two localities, Craters of the Moon National Monument and Preserve, Idaho and the 2014-2015 Holuhraun lava flow-field. We focus on using SAR data in this study for two reasons, (1) improve our understanding on how radar surface roughness can be connected to the emplacement mechanisms of volcanic and impact melt, and (2) to highlight the techniques capabilities and limitations for differentiating different lava flow types and lava facies. Impact melt has contrasting intrinsic properties and geologic origins to lava flows, so we include the analysis of a physical property of impact melts that influences melt behaviour. To complement our radar surface roughness analysis, we seek to constrain the temperature of the Mistastin Lake impact structure impact melt deposits by analyzing the crystallographic orientations and microstructures of zircon grains and zirconia crystals encased in melt-bearing impactites. We demonstrate in this work that without entirely understanding the capabilities and limitations of using SAR for lava flow differentiation, we will struggle to interpret the eruption dynamics and history of volcanic landforms on terrestrial bodies, which in turn limits what we can learn about impact melt emplacement. Furthermore, we discover that high temperature and pressure conditions can be constrained from an impact environment that was once superheated, which has strong implications for discovering high P-T shock indicators in other terrestrial impact structures and also in lunar impactites. In addition, our work has strong applications towards addressing high priority science goals established by research groups such as the Lunar Exploration Analysis Group

Deriving Planetary Surface Characteristics from Orbiting Laser Altimeter Pulse-Widths on: Mars, the Moon, and Earth

A set of equations linking the time-spread of a laser altimeter echo-profile, commonly known as the pulse-width, to the variance of topography within the pulse-footprint are tested by comparing pulse-width data to surface characteristics measured from high-resolution Digital Terrain Models. The research is motivated by the advent of high-resolution Digital Terrain Models over Mars, which enables the calibration of Mars Orbiter Laser Altimeter pulse-widths, and evolves to include lunar and terrestrial data in an attempt to validate the theory and develop new methods. Analysis of Mars Orbiter Laser Altimeter pulse-width data reveals mixed results. Over homo- geneously rough terrain, at kilometre-scales, these pulse-widths show some correlation to surface characteristics, once poor pulse data has been removed. However, where roughness is highly vari- able over short baselines, little correlation is observed, which is attributed to a mix of georeferencing errors and instrument methods. In a similar study, Lunar Orbiter Laser Altimeter pulse-widths are shown to produce only poor correlations with surface characteristics over local study sites. Instead, the observed correlations differ from orbit to orbit, with the majority of those used appearing to contain poor quality pulse- width data - attributed to the instrument methods - and only 14 % revealing correlations similar, or better, than observed over Mars. Finally, an examination of the relationship between footprint-scale surface characteristics and pulse-width estimates derived from smoothed Ice, Cloud, and land Elevation Satellite echo-profiles enables different pulse-width thresholds to be tested. Here, pulse-widths measured using a 10 % Peak Energy threshold are shown to produce greater correlations than those observed using the Mars Orbiter Laser Altimeter and the Lunar Orbiter Laser Altimeter data, which use a Full Width Half Maximum threshold. To conclude, pulse-widths can show strong correlations to surface roughness and slope within the pulse-footprint. However the assumption that detrended surface roughness can be derived by applying a slope contribution effect is shown to be unfounded. The principal recommendation is for future instruments to use a full echo-profile in estimating pulse-width values at a 10 % Peak Energy threshold, providing both efficient noise removal and a better correlated dataset