We will cover critical aspects of lunar science, including the deep interior, subsurface structure, surface morphology, up to atmospheric dynamics and the solar wind interaction. Such studies can make use of lunar mission data, lunar samples, meteorites, terrestrial analogues, laboratory experiments, and / or modeling efforts.
Furthermore, highlighting results from past and current space missions, this session seeks to explore innovative ideas for future exploration, including insights on forthcoming space missions and instrumentation aiming to greatly advance our understanding of the Moon in the next decades. In addition, the session will focus on identifying strategic knowledge gaps crucial for the safe and sustainable exploration of cis-lunar space and the lunar surface by astronauts.
We welcome all relevant contributions — spanning theoretical models, observational data, and experimental findings — from experts of different fields including science and engineering. As such, the session aims to foster a comprehensive dialogue on the status and future of lunar exploration.
Orals: Tue, 5 May, 14:00–10:50 | Room E2
Blue Ghost Mission 1 (BGM1), or NASA CLPS (Commercial Lunar Payload Services) Task Order (TO) 19D, delivered ten NASA science and technology instruments to the lunar surface (18.5623°N, 61.8103°E) in 2025. All NASA payloads successfully activated and performed operations on the Moon:
LuGRE (Lunar GNSS Receiver Experiment) acquired and tracked Global Navigation Satellite System (GNSS) signals from GPS and Galileo constellations and calculated instantaneous navigation “fixes” enroute to and on the Moon’s surface for the first time. LuGRE demonstrated that GNSS signals can be used to support navigation in cislunar space and at the Moon.
RadPC (Radiation Tolerant Computer System) successfully operated through Earth’s Van Allen belts, in transit to and in lunar orbit, and on the lunar surface. RadPC verified solutions to mitigate radiation effects on computers that could make future missions safer for equipment and more cost effective.
EDS (Electrodynamic Dust Shield) successfully lifted and removed lunar regolith from surfaces using electrodynamic forces demonstrating a promising solution for dust mitigation on future lunar and interplanetary surface operations.
SCALPSS (Stereo Cameras for Lunar Plume-Surface Studies) captured more than 9,000 images including during the spacecraft’s descent to the surface, providing insights into the effects engine plumes have on the surface. The payload also operated on the surface during the lunar day, during the lunar sunset, and into the lunar night.
LISTER (Lunar Instrumentation for Subsurface Thermal Exploration with Rapidity) is now the deepest robotic planetary subsurface thermal probe, drilling and acquiring thermal measurements at eight depths down to ~1-m depth. LISTER provided a first-time demonstration of robotic thermal measurements at varying depths.
LMS (Lunar Magnetotelluric Sounder) determined that the subsurface electrical conductivity profile beneath the Blue Ghost lunar lander is very similar to that below the Apollo 12 site. This implies that the widespread basaltic volcanism of the western nearside was not powered by regional enhancement of heat-producing elements, but was likely a consequence of easier eruption through thinner crust.
LEXI (Lunar Environment heliospheric X-ray Imager) captured X-ray images to study the interaction of the solar wind and Earth’s magnetic field to provide insights into how space weather and other cosmic forces surrounding Earth affect the planet. LEXI also observed density profiles of the lunar exosphere through solar wind charge-exchange emission.
NGLR (Next Generation Lunar Retroreflector) has successfully reflected and returned laser light for thousands of individual range measurements from multiple Lunar Laser Ranging Observatories (LLROs) on Earth. Measurements utilizing NGLR will enable precise measurements of the Moon’s shape and distance from Earth, expanding our understanding of the Moon’s inner structure.
LPV (Lunar PlanetVac) was deployed on the lander’s surface access arm and collected, transferred, and sorted lunar regolith particles using pressurized nitrogen gas, including acquiring regolith without physically touching the lunar surface. LPV successfully demonstrated a low-cost, low-mass solution for future robotic sample collection.
RAC (Regolith Adherence Characterization) examined how regolith sticks to a range of materials exposed to the lunar environment. Results can help test, improve, and protect spacecraft, spacesuits, and habitats from abrasive lunar dust.
How to cite: Banks, M. and the EDS team, LEXI team, LISTER team, LMS team, LPV team, LuGRE team, NGLR team, RadPC team, RAC team, SCALPSS team: Overview of the NASA instruments onboard Blue Ghost Mission 1, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22820, https://doi.org/10.5194/egusphere-egu26-22820, 2026.
On March 2, 2025, Firefly Aerospace became the first United States-based company to successfully soft-land a robotic spacecraft on the Moon. The Blue Ghost lander deployed all 10 NASA-supported payloads under the Commercial Lunar Payload Services. The Lunar Instrumentation for Subsurface Thermal Exploration with Rapidity (LISTER) was one of them. LISTER measured temperature and thermal conductivity of the lunar regolith of the landing site at 8 depths down to 1 m for the purpose of quantifying the endogenic heat flow of the Moon. To penetrate to the subsurface, LISTER used the pneumatic excavation technique in which the deployment mechanism spooled out a 6.4-mm diameter stainless steel tube and blew pressurized nitrogen gas through a nozzle attached to the leading end of the tube. The gas jet, rapidly expanding in the lunar vacuum, removed the regolith ahead of the nozzle, while the spooling motor applied weight to advance deeper into the subsurface. The thermal sensors were encased in a stainless-steel needle, 28-mm long and 2.8-mm diameter, attached to the gas nozzle. When the needle sensor reached a depth targeted for thermal measurements, LISTER stopped the gas jet and inserted the needle into the bottom-hole regolith. Each thermal measurement sequence took 2 hours. During the first hour, the needle thermally equilibrated with the regolith. Then, the needle was electrically heated with a constant power of 50 mW for 30 minutes, followed by a 30-minute cool-off period. Thermal conductivity of the regolith was determined by modeling the rise and fall of the needle temperature during the 2nd hour using a finite-element heat transfer model.
Prior to the mission, it was hoped that LISTER would reach greater than 1-m depth into the subsurface, where temperature of the regolith is not significantly affected by the insolation cycles. Then, the endogenic heat flow would have been obtained simply as the product of the thermal gradient and the thermal conductivity of the regolith depth interval penetrated. Because LISTER did not reach that depth, the heat flow is being determined as the lower boundary condition for a one-dimensional (vertical) finite-element heat transport model that simulates the interaction between the upward flow of the endogenic heat and the downward propagation of the insolation-induced thermal waves. The history of the insolation-induced surface temperature swings at the landing site, which is the surface boundary condition for the heat transport model, has been reconstructed from the ephemeris of the landing site and surface temperatures determined from flyovers by the Diviner radiometer onboard the Lunar Reconnaissance Orbiter. The equilibrium temperature and thermal conductivity of the regolith determined at 8 depths by LISTER provide key constraints to the model. Our early results suggest endogenic heat flow values of 13 to 14 mW/m2, comparable to what was observed at the Apollo 17 site (16 mW/m2). A more thorough inversion is now being carried out to optimize the heat flow determination and estimate its uncertainty.
How to cite: Nagihara, S., Zacny, K., Ngo, P., Sanasarian, L., Misra, R., Grott, M., Knollenberg, J., Smrekar, S., Siegler, M., and Neal, C.: First robotic attempt to measure heat flow of the Moon: Deployment of LISTER on Blue Ghost Mission One to Mare Crisium, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6066, https://doi.org/10.5194/egusphere-egu26-6066, 2026.
Blue Ghost Mission 1 (BGM1) landed on the Moon in Mare Crisium (18.562 °N, 61.810 °E) on March 3, 2025. It deployed the lunar magnetotelluric sounder (LMS), the first extraterrestrial MT experiment, designed to investigate upper mantle electrical conductivity and temperature, outside the Moon’s Procellarum KREEP Terrane (PKT). The PKT exhibits extensive mare volcanism and surficial heat-producing elements (HPE), but their causal relationship remains unclear. Specificially, the amount and depth distribution of HPE elements beneath the PKT is unknown and various models have different implications for mantle temperature. Mantle electrical conductivity has previously been investigated at the Apollo 12 (A12) site, and new data acquired from BGM1 provide the opportunity to compare electrical conductivity profiles and inferred mantle temperatures beneath sites inside (A12) and outside (BGM1) the PKT.
LMS operated until March 12, 2025. Comparison of vector magnetic field data from LMS and the ARTEMIS THEMIS-B orbiting spacecraft show the transit through the solar wind, the magnetosheath and the magnetotail, with bow shock crossings and the magnetotail current sheet crossing clearly observed in LMS data.
A landing site with small crustal fields was desirable for the electrical conductivity experiment to minimize plasma interactions. Satellite-based models predict surface fields of less than 10 nT at BGM1. Although measurement of crustal fields was not a science requirement or objective, determination of the static field has been possible and it can be demonstrated to be of primarily crustal (not spacecraft) origin. The resulting surface field of ~65 nT reflects only modest additional contributions from magnetizations not observable from orbit.
The magnetotelluric (MT) method uses orthogonal horizontal components of local time-varying electric and magnetic fields to determine subsurface electrical conductivity. However, a combination of plasma conductivity 10x higher than expected and magnetometer placement relatively far from the surface resulted in a frequency-dependent attenuation of the induction signal. Although MT produces plausible results, we focus on electrical conductivity results obtained using the magnetic Transfer Function (TF) approach, that compares fields measured at the surface to those measured at distance from the Moon. We compare LMS measurements at BGM1 with reference magnetic fields measured by THEMIS-B to obtain TF at BGM1, and invert these for electrical conductivity. We also reinvert TFs computed using A12 surface fields and those measured simultaneously by the distant Explorer 35 orbiter. We find that the temperature difference between A12 and BGM1 derived from electrical conductivity is <100 K (+1-sigma level) at 200-km depth. This is incompatible with excess HPE abundances required for PKT-centric partial melting throughout lunar history. We suggest that the thin crust at PKT led to preferential eruption of mare basalts, and preferential excavation of globally distributed urKREEP. We conclude that regional volcanism and surficial incompatible elements in PKT are not genetically related.
LMS Team: R. Grimm (PI), G. Delory, J. Espley, I. Garrick-Bethel, J. Gruesbeck, S. Howard, C. Johnson, R. Maxwell, C. Neal, T. Nguyen, R. Nolan, M. Phillips, M. Purucker, D. Sheppard, F. Simpson, C. Smith, T. Smith, D. Stillman, T. Taylor, P. Turin.
How to cite: Johnson, C. L., Grimm, R. E., Espley, J., Garrick-Bethel, I., Howard, S. K., Maxwell, R. E., Neal, C. R., and Stillman, D. E.: Results from the Lunar Magnetotelluric Sounder on Blue Ghost Mission 1, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8526, https://doi.org/10.5194/egusphere-egu26-8526, 2026.
Lunar magnetic field investigation connects the interior, the surface, and the space environment of the Moon. Measuring and understanding the lunar magnetic field at different length-scales and time-scales is of critical importance to understand the bulk water content and temperature profile in the lunar mantle, the existence and properties of a partial melt layer above the lunar core, the size of the lunar core, the origin of volatiles on the lunar surface, and the origin and properties of the past lunar dynamo, all of which are intimately connected to the origin of the Earth-Moon system and the subsequent thermal-chemical-environmental evolution of the Moon. The surface of the Moon, however, is a challenging environment, including contrasting temperatures between lunar day and lunar night, dust, and surface charging.
Here we report our progress in the designing, building, and testing of a temperature-stabilized fluxgate magnetometer (FGM) system for long-term operations on the surface of the Moon. We refer to this FGM system configuration as L-MAG. The sensor design draws heritage from those onboard the NASA Magnetospheric Multiscale (MMS) mission, InSight Mars Lander, the Europa Clipper mission, and most recently the TRACERS mission. One of the key improvements is a magnetically clean AC heater that directly surrounds the FGM sensor, improving power efficiency and responsiveness compared to Europa Clipper Magnetometer’s distant heater pod. Thermal losses are reduced with a low-emissivity enclosure and lightweight Kapton flex harness. The heater system is designed to yield a temperature stability of ± 0.1 degrees °C around two set-point temperatures (day and night) to further reduce long-term drift, allowing the inference of lunar induction responses at periods of 105 seconds and longer, necessary to probe the lower lunar mantle and core. This power efficient FGM design will be compatible with installation onto a lunar lander or placed on the surface of the moon by an astronaut. Our L-MAG system will significantly improve measurement capabilities for upcoming lunar science missions including those via the Commercial Lunar Payload Services (CLPS) and via Artemis astronaut deployments.
How to cite: Cao, H., Strangeway, R., Khurana, K., Caron, R., McDowell, E., Pierce, D., Hinkley, D., and Walsh, N.: L-MAG: A Temperature-Stabilized Fluxgate Magnetometer System for Long-Term Lunar Surface Observatories, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3637, https://doi.org/10.5194/egusphere-egu26-3637, 2026.
The Chemistry, Organics and Dating Experiment (CODEX) is a compact, dual-mode laser-ablation time-of-flight mass spectrometer developed for the DIMPLE payload (CLPS CP-32) to provide co-registered geochemical context and in situ Rb–Sr chronometry on the lunar surface. DIMPLE targets Ina, among the largest irregular mare patches (IMPs), to test whether IMPs record geologically recent volcanism or instead reflect ancient, highly vesicular basaltic deposits with poor small-crater preservation. Absolute ages tied to measured composition are required because morphology and crater statistics alone are ambiguous for these terrains. The CODEX architecture couples 266 nm UV laser-ablation mass spectrometry (LAMS) for major and trace-element mapping (m/z 1–250) with laser-ablation resonance-ionization mass spectrometry (LARIMS) for selective, interference-free Rb and Sr isotope measurements that mitigate the 87Rb/87Sr isobar without relying on extreme mass resolving power. We are currently commissioning the CODEX Engineering Development Unit (EDU). First LAMS measurements on calibration samples show m/Δm ≈ 300–400 (FWHM) across the targeted range and clear isotopic structure (e.g., resolved Fe and Pb isotopes), indicating robust transmission and margin for compositional mapping. Ongoing work is extending these EDU results toward resonance-ionization operation to validate the end-to-end Rb–Sr measurement chain and quantify isotope performance under representative conditions.
How to cite: Fausch, R., Anderson, F. S., Aebi, A. E., Alexander, A. M., Bierhaus, E. B., Braden, S. E., Fagan, A. L., Ferguson, S. N., Head III, J. W., Iseli, A. M., Joy, K. H., Korsmeyer, J. M., Levine, J., Osterman, S., Pernet-Fisher, J. F., Singh, V., Tartèse, R., Teichmann, T. L., Wurz, P., and Yant, M. A.: In situ Rb–Sr geochronology and geochemistry to constrain lunar volcanism, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6654, https://doi.org/10.5194/egusphere-egu26-6654, 2026.
In Situ Resource Utilization (ISRU) is being proposed as the strategy to establish long-term presence on the Moon and to facilitate future crewed missions farther, e.g., Mars, thanks to the creation of products by using local resources [1]. Due to its composition and physical characteristics, lunar regolith represents a key resource for human life support, propellant production, and the construction of infrastructures [2-4]. The development of efficient regolith sampling technologies hence represents a crucial first step to increase our understanding of lunar resources. Within the previous exploration missions on the Moon and recent technology developments, several approached have been proposed for the collection of regolith [5]. There has been great attention in optimizing technology performance, however developing systems capable of acquiring regolith samples that are representative of the sampled region is still a necessity [5].
The present work proposes the design, development and testing of a system employing electrostatic and vibration forces to execute a precise and representative sampling of surface lunar regolith. The sampling system was tested at controlled relative humidity conditions at the European Space Resources Innovation Centre (ESRIC) in Luxembourg. Samples of LHS-1 lunar regolith simulant with changing compaction levels were created using air pluviation technique as previously done in [6]. Our findings showed greater regolith collection for LHS-1 samples with lower initial porosity. Sampling performance was also evaluated with changing environment relative humidity (RH) conditions showing greater regolith collection with decreasing RH for values below 18 %, after which it was constant. In addition, how sampling performance is affected by the process duration was investigated resulting in greater mass collected during longer operations for processes up to 360 s, after which saturation was observed. Finally, for the first time, the Particle Size Distributions of collected and original regolith samples were measured and the mean values of particle size diameters did not show important relative differences, demonstrating the representativity of the proposed sampling system.
[1] G. B. Sanders, “Advancing In Situ Resource Utilization Capabilities To Achieve a New Paradigm in Space Exploration,” in 2018 AIAA SPACE and Astronautics Forum and Exposition, Orlando, FL: American Institute of Aeronautics and Astronautics, Sep. 2018. doi: 10.2514/6.2018-5124.
[2] I. A. Crawford, “Lunar resources: A review,” Prog. Phys. Geogr. Earth Environ., vol. 39, no. 2, pp. 137–167, Apr. 2015, doi: 10.1177/0309133314567585.
[3] M. B. Duke, “Development of the Moon,” Rev. Mineral. Geochem., vol. 60, no. 1, pp. 597–655, Jan. 2006, doi: 10.2138/rmg.2006.60.6.
[4] M. Anand et al., “A brief review of chemical and mineralogical resources on the Moon and likely initial in situ resource utilization (ISRU) applications,” Planet. Space Sci., vol. 74, no. 1, pp. 42–48, Dec. 2012, doi: 10.1016/j.pss.2012.08.012.
[5] S.R.M. Pirrone et al., “Lunar Regolith Sampling Technologies: A Critical Review“, Space Sci Rev 221, 111, Nov. 2025, doi: 10.1007/s11214-025-01239-6.
[6] S.R.M. Pirrone et al., “The Effect of Tip Design on Technological Performance During the Exploration of Earth, Lunar, and Martian Soil Environments,” J. Field Robot., p. rob.70043, Aug. 2025, doi: 10.1002/rob.70043.
How to cite: Pirrone, S. R. M., Patil, T., Dillenburger, J., Shanbhag, A., and Hadler, K.: Electrostatic-driven method for lunar regolith sampling, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8051, https://doi.org/10.5194/egusphere-egu26-8051, 2026.
With near-future manned space exploration expanding beyond low Earth orbit out toward the Moon and beyond, there is a critical need to understand how a sustained human lunar presence can be supported through in-situ resource utilization (ISRU), as transporting supplies to the lunar surface remains technically challenging and costly(Y. Gumulya et al., Minerals Engineering, 2022; R. Santomartino et al., Nature Communications, 2023). Biomining, a terrestrial biotechnology that employs microorganisms to mobilize useful elements from rock, represents a promising approach for space-based ISRU. Recent biomining experiments aboard the International Space Station (ISS), including BioRock using Martian rock analogs and BioAsteroid using meteoritic material, have demonstrated that microbial mobilization of economically and ISRU-relevant elements is feasible in space(C. S. Cockell et al., Nature Communications, 2020; R. Santomartino et al., in review). However, biomining of lunar(-like) material, particularly under lunar-like gravitational conditions, has not yet been explored. For lunar-specific biomining, heterotrophic organisms might be more suitable than chemolithotroph ones, due to their capacity to bioleach silicon-rich minerals. The use of cyanobacterial biomass as a reusable “nutrient cartridge” to support their organics requirement in space represents a key but untested component of closed-loop ISRU systems (R. Santomartino et al., Nature Communications, 2023; C. Verseux et al., Frontiers in Microbiology, 2021).
Here, we propose an ISS experiment to investigate biomining of lunar KREEP-like material under multiple gravity regimes. The primary objectives are to (1) quantify biomining performance on lunar(-like) substrates under simulated lunar gravity, (2) compare biomining efficiency across multiple gravitational conditions, (3) test whether cyanobacterial biomass enhances biomining performance, and (4) demonstrate metabolic coupling between autotrophic biomass and heterotrophic microorganisms under lunar-relevant gravity. The experiment will employ flight-proven bioreactor hardware containing Sphingomonas desiccabilis, a microorganism previously shown to biomine rock under spaceflight conditions, partially supplied with stable isotope-labelled biomass derived from Anabaena cylindrica. Biomass from this cyanobacterium, which is being studied for its ability to grow from resources available on the Moon or Mars, has previously been demonstrated to support the heterotrophic growth of other organisms.
Incubations will be conducted within the existing KUBIK facility aboard the ISS, which provides controlled temperature conditions and simulated gravity environments. Following sample return to Earth, a combination of microbiological, chemical, isotopic, and geological analyses will be performed to assess microbial activity, element mobilization, and metabolic coupling. Multiple gravity regimes, along with Earth-based ground controls, will allow direct evaluation of gravitational effects on biomining efficiency and microbial physiology.
We expect to observe measurable mobilization of rare earth and other ISRU-relevant elements from the mineral substrate, as well as isotopic signatures indicating utilization of cyanobacterial biomass by S. desiccabilis. Differences in metal-leaching efficiency and microbial responses across gravity conditions are anticipated. This experiment will provide the first proof-of-concept demonstration of biologically mediated loop-closure relevant to lunar ISRU, informing future strategies for sustainable lunar exploration and advancing our understanding of microbe-mineral interactions beyond Earth.
How to cite: Acciardo, A., Santomartino, R., Cockell, C., Magnabosco, C., Busemann, H., Leya, I., Verseux, C., and Vorburger, A.: Biomining of Lunar-Relevant Materials under Simulated Lunar Gravity on the International Space Station, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14643, https://doi.org/10.5194/egusphere-egu26-14643, 2026.
Human space exploration is progressively moving toward long-duration missions and permanent human presence on the Moon and Mars. Achieving these ambitious goals requires overcoming major scientific and technological challenges. Among these, habitability requires the development of Bioregenerative Life Support Systems (BLSS), capable of regenerating essential resources and reducing resupply from Earth. Within BLSS, higher plants play a central role, contributing to oxygen production, carbon dioxide removal, water purification, waste recycling, and fresh food supply. The cultivation of plants in space also supports human well-being by alleviating psychological and physiological stress of prolonged isolation and confinement. In fact, the green environments, apart from filtering airborne contaminants, improve psychological relief, emotional stability, and enhance cognitive functions while reducing pain perception. Moreover, the introduction of fresh food in astronauts’ diet contributes to a more balanced diet rich in active compounds, including vitamins, antioxidants, and polyphenols, with both physiological and psychological benefits.
Therefore, plant cultivation in space is increasingly recognized as a key element for crew support by the International Space Exploration Coordination Group (ISECG) within the priority areas, “Life Support and Habitability” and “Crew Health and Performance”.
One of the most critical constraints in extraterrestrial environments is exposure to high levels of ionizing radiation (IR) that significantly influences organism growth and development through molecular alterations, disrupted morphogenesis, and physiological stress responses
Although it is well documented that plants are much more resistant to IR compared to animals, IR can still compromise the efficiency of plants as resource regenerators in BLSS and alter the balance of inputs and outputs among the sub-compartments. Therefore, a thorough understanding of plant responses to radiation is essential for the design and optimization of space greenhouses. However, the exposure to IR at specific doses can enhance plant defense mechanisms, inducing a pre-acclimation response that increases tolerance to subsequent stresses. The PRIMO Project (Priming Radiation-Induced plants’ adaptation to MOon: make an enemy your friend), selected by the European Space Agency (ESA) within the ESA SciSpacE AO - Reserve Pool Of Science Activities for the Moon aims to investigate whether the pre-irradiation of seeds on Earth can enhance plant resistance to the Moon’s environment. The Italian Space Agency (ASI) has funded the preparation of the pre-flight phase of the project, in which seeds of different plant species will be pre-irradiated on Earth using different types and doses of ionizing radiation. Both treated and non-treated (control) seeds will be exposed to the Lunar radiation conditions and reduced gravity throughout the mission duration. After sample recovery, cultivation trials will be conducted under controlled conditions on Earth. Plant performance will be evaluated through growth analysis, transcriptomic profiling, physiological and anatomical assessments, and nutritional quality measurements, providing insights into the feasibility of radiation-based strategies to support sustainable plant cultivation in future lunar BLSS. The approach of PRIMO will allow exploiting the beneficial effects of low-dose radiation to enhance plant tolerance to abiotic stresses, transforming IR from a limiting factor into a potential tool to improve plant resilience to space-related stressors.
How to cite: De Micco, V., Amitrano, C., De Francesco, S., Pannico, A., Durante, M., Pugliese, M., Arena, C., Caputo, R., De Pascale, S., Perilli, S., and Del Bianco, M.: Plant-based life support systems: priming plants’ adaptation to the Moon through ionizing radiation within the PRIMO project , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20636, https://doi.org/10.5194/egusphere-egu26-20636, 2026.
Lunar magnetic anomalies (LMAs) are small regions (on the order of 100 km) of crustal magnetic fields on the lunar surface with field strengths of about 100 nT [1, 2]. Spacecraft measurements and numerical modeling of the interaction between the solar wind and the LMAs predict the formation of mini-magnetospheres [3], where the field strength magnetizes electrons but not ions. The separation between the electrons tied to the field lines and the less restrained ions produces strong electric fields (≈ 0.150 V m−1) near the lunar surface [1]. At SPACE Laboratory, we are studying if this polarization electric field and the solar wind particle flux can be used for power extraction on the lunar surface using 3D particle-in-cell (PIC) modeling [4] and a subscale experiment. The figure shows key aspects employed to simulate mini-magnetosphere physics in the PIC code (left) and the experiment (right): (1) a plasma representing the solar wind, (2) a magnetic dipole field representing the LMA, (3) the lunar surface plane, (4) a current emitting cathode that enhances and allows power draw into an external load, and (5) an anode where electron precipitation balances the load current. The simulation imposes sheath electric field conditions at the electrodes [5, 6] to model the interaction with the plasma.
This work presents results from a study of mini-magnetosphere structure under various solar wind conditions, such as varying incidence angle, density, and speed, and discusses how the changing plasma dynamics would affect power extraction. Results show that net positive power in the sub-kilowatt range can be extracted from the mini-magnetosphere under favorable conditions with the injection of an electron current from the cathode and the collection of sufficient charged particles at the anode. PIC simulations show that the stability of the power generation scheme depends on the stability of the mini-magnetosphere structure, which is sensitive to the cathode electron injection. Moreover, the solar wind incidence angle is found to be a major factor in determining the power that could be generated with fixed electrodes since the mini-magnetosphere structure stretches in the direction of the wind. The subscale experiment corroborates many of the physical phenomena predicted by the simulations, lending credence to the findings. Based on the physical insights, we propose engineering solutions that could enable this technology to provide power for lunar exploration missions.
References: [1] Deca J. et al. In: Journal of Geophysical Research: Space Physics 120.8 (2015), pp. 6443–6463. [2] Bamford R. A. et al. In: The Astrophysical Journal 830.2 (2016), p. 146. [3] Deca J. et al. In: Physical Review Letters 112.15 (2014), p. 151102. [4] Markidis S. et al. In: Mathematics and Computers in Simulation 80.7 (2010), pp. 1509–1519. [5] Skolar C. R. et al. In: Physics of Plasmas 30.1 (2023), p. 012504. [6] Baalrud S. D. et al. In: Plasma Sources Science and Technology 29.5 (2020), p. 053001.
How to cite: Sharma, A., Rae, P., Krishna Kumar, V., Deca, J., and Little, J.: Particle-In-Cell and Experimental Study of Lunar Mini-Magnetospheres for Power Extraction, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16079, https://doi.org/10.5194/egusphere-egu26-16079, 2026.
Orals: Fri, 8 May, 10:45–12:30 | Room L3
The last giant impact on Earth is thought to have formed the Moon. The timing of this event can be determined by dating the different rocks assumed to have crystallized from the lunar magma ocean (LMO). This has led to a wide range of estimates for the age of the Moon between 4.35 and 4.51 billion years ago (Ga), depending on whether ages for lunar whole-rock samples or individual zircon grains are used. Here we argue that the frequent occurrence of approximately 4.35-Ga ages among lunar rocks and a spike in zircon ages at about the same time is indicative of a remelting event driven by the Moon's orbital evolution rather than the original crystallization of the LMO. We show that during passage through the Laplace plane transition, the Moon experienced sufficient tidal heating and melting to reset the formation ages of most lunar samples, while retaining an earlier frozen-in shape and rare, earlier-formed zircons. This paradigm reconciles existing discrepancies in estimates for the crystallization time of the LMO, and permits formation of the Moon within a few tens of million years of Solar System formation, consistent with dynamical models of terrestrial planet formation. Remelting of the Moon also explains the lower number of lunar impact basins than expected, and allows metal from planetesimals accreted to the Moon after its formation to be removed to the lunar core, explaining the apparent deficit of such materials in the Moon compared with Earth. We will also discuss how the Moon could have reached the Laplace Plane Transition so late during its tidal evolution.
How to cite: Morbidelli, A., Nimmo, F., and Kleine, T.: Tidally driven remelting of the Moon around 4.35 billion years ago, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8778, https://doi.org/10.5194/egusphere-egu26-8778, 2026.
The Moon’s ancient magnetic field provides critical insights into its thermal and magnetic evolution, yet the lifetime of its dynamo remains debated. Returned samples yield complex and contradictory paleomagnetic records, while orbital data reveal crustal magnetic anomalies of uncertain origin from either a core dynamo or transient impact-generated fields. Here we jointly invert gravity and magnetic observations in the region around the Dewar swirl, a high-albedo feature associated with the Dewar magnetic anomaly. We identify a shallow, magnetized, high-density body consistent with buried mare basalt. Its formation requires paleointensity exceeding 11 μT, suggesting a lunar dynamo was active at about 4.2 Ga, as constrained by the superposed basin ejecta. Results also show that swirl formation requires horizontal magnetization and iron oxide enrichment. These findings link a magnetic anomaly to its geologic source and the state of the lunar dynamo, providing new constraints on the lunar magnetic and volcanic history.
How to cite: Yang, X., Mittelholz, A., Broquet, A., and Moorkamp, M.: Magmatic origin of the Dewar magnetic anomaly: Implications for an early lunar dynamo, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2285, https://doi.org/10.5194/egusphere-egu26-2285, 2026.
We report improved mapping of crustal magnetic anomalies near the lunar poles using a combination of Lunar Prospector and Kaguya orbital magnetometer data. In agreement with previous results, a concentration of moderately strong magnetic anomalies is centered approximately on the south polar region. In contrast, only a single verified anomaly is present in the north polar region. Published analyses of Kaguya spectral profiler and LOLA albedo data have shown that an area of relatively low optical maturity and high surface albedo is present in the south polar region whereas the north polar region is mostly optically mature. Comparing our magnetic field maps to published albedo maps (D. Moriarty and N. Petro, JGR, 2024), possible curvilinear albedo markings (“swirls”) of the Reiner Gamma class are present where the strongest anomalies near the south pole are found. In the north polar region, a single albedo anomaly is present just poleward of the single magnetic anomaly. In view of previous work showing that solar wind ion deflection associated with crustal magnetic fields can lead to surface optical immaturity, higher surface albedo, and swirl formation, the empirical evidence reported here supports the hypothesis that the magnetic anomalies near the south pole are capable of significant solar wind ion flux reductions.
Previous analyses of Moon Mineralogy Mapper (M3) data have also found that more inferred water ice exposures are present near the south pole than near the north pole (S. Li et al., PNAS, 2018). We have previously reported particle-in-cell simulations of the surface plasma flux and water ice lifetimes against solar wind ion sputtering in this region, taking into account crustal magnetic fields as well as topography (J. Deca et al., 2025 LPSC; 2026 LPSC). These simulations demonstrate a correlation between areas of long sputtering lifetimes and areas with more numerous water ice exposures. Further simulations using the improved crustal field maps are in progress and will be presented at the meeting.
How to cite: Hood, L., Deca, J., Li, S., and Moriarty, D.: Magnetic Anomalies Near the Lunar South Pole and Their Consequences , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12596, https://doi.org/10.5194/egusphere-egu26-12596, 2026.
Lunar magnetic anomalies are abundant near the south pole, where several moderate-strength anomalies spatially overlap permanently shadowed regions. This environment provides a unique setting to assess how crustal magnetic fields and complex topography regulate plasma–surface interactions and, in turn, the stability and distribution of surface water ice.
A global fully kinetic electromagnetic particle-in-cell numerical model is used to simulate proton and electron surface fluxes near the south pole, averaged over a full lunar rotation. The simulations incorporate a regional crustal magnetic field model based on Kaguya and Lunar Prospector magnetometer measurements, together with high-resolution surface topography from the Lunar Reconnaissance Orbiter Laser Altimeter. This approach enables a self-consistent evaluation of how terrain and crustal magnetic fields jointly influence plasma access to the surface.
The simulations show that topography strongly structures the surface plasma environment, enhancing fluxes on crater walls while partially shielding crater floors. The inclusion of crustal magnetic fields further modulates plasma access, producing relatively modest proton and electron flux variations relative to simulations without magnetic anomalies.
Using the modelled fluxes, plasma-driven production, sputtering, and electron-stimulated desorption rates are evaluated alongside thermally driven sublimation. While the absolute balance depends on laboratory-derived yield assumptions, the results indicate that permanently shadowed regions consistently exhibit a positive net surface water ice balance rate, which closely coincides with inferred surface water ice exposures and highlights the importance of including realistic crustal magnetic fields and topography when assessing plasma-surface interactions and volatile evolution at the lunar poles.
How to cite: Deca, J., Hood, L., and Li, S.: The Role of Crustal Magnetic Anomalies and Topography in Shaping Lunar South Polar Water Ice, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8795, https://doi.org/10.5194/egusphere-egu26-8795, 2026.
Sample return from the Moon’s South Pole-Aitken Basin (SPA) has long been recognized as a high priority destination for lunar science, appearing as a recommended medium-class NASA mission in multiple United States National Academies of Sciences Planetary Science decadal surveys. The primacy of the site arises from the unique combination of its size, antiquity, and location on the lunar farside. The South Pole-Aitken basin presents the ideal target destination to test nearly 60 years of lunar science hypotheses. Despite the recognized importance of the science, mission proposals for sample return have previously been hampered by a combination of costs and technology. During the development of the 2023-2032 Origins, Worlds, and Life (OWL) decadal survey, a mission concept named “Endurance” demonstrated the feasibility of a long-duration, long-traverse mission that could accomplish the majority of defined priority lunar science investigations at a cost cap that was commensurate with New Frontiers scale missions. This mission concept leveraged new developments in rover technology, autonomous systems development, and concepts of operations developed by the Intrepid Pre-decadal Mission Concept Study, in conjunction with the advent of technological advances in the commercial exploration marketplace. Using the Endurance point design, the OWL advocated for the development of an SPA Sample Return mission as the highest priority mission for the Lunar Discovery and Exploration Program (LDEP). In response to this recommendation, NASA convened the South Pole Aitken basin sample Return and eXploration (SPARX) Science Definition Team (SDT) to provide analysis on prioritized science objectives and implementation architectures for a South Pole-Aitken Basin sample return mission.
The SPARX SDT report will be released to the community in Spring 2026, following review by NASA. The report will include descriptions of prioritized science goals and objectives and the associated requirements for both in-situ and terrestrial laboratory measurements. The report will provide a description of a baseline implementation architecture that demonstrates a notional traverse and mission architecture for accomplishing all of the listed science objectives. Additionally, the report will include a discussion of multiple mission implementation profiles, with recommendations for their future selection criteria. Finally, the report will contain a discussion of future technologic and programmatic factors that could affect the future implementation of the mission, including the role of astronauts, commercial exploration, and international participation. This presentation will provide an overview of the newly released SPARX report, focusing on the overarching recommendations for implementation architectures, measurement requirements, and high-priority items for the next phases of mission development.
How to cite: Jozwiak, L. and the South Pole Aitken basin sample Return and eXploration (SPARX) Science Definition Team: South Pole-Aitken basin sample Return and eXploration (SPARX) Science Definition Team Report: Findings and Recommendations for a Future Lunar Mission, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15867, https://doi.org/10.5194/egusphere-egu26-15867, 2026.
Characterizing the radiation environment on the lunar surface is essential for a safe human and robotic exploration. Having a negligible atmosphere, the Moon is exposed to galactic cosmic rays (GCRs), a continuous high flux of very energetic particles, and solar energetic particles (SEPs), which are accelerated in the solar corona or in coronal mass ejections. These particles can damage biological, electronic systems and other materials and thus hinder or even terminate space missions.
To aid future mission planning and habitat design, we developed a Geant4 based model, LUNAIRE, that simulates GCR and SEP propagation through the lunar surface. The model accounts for secondary particle generation on the sub-surface and derives physical quantities such as absorbed dose and Linear Energy Transfer (LET) spectrum at the surface and underground. This model was adapted from the detailed Mars Energetic Radiation Environment (dMEREM) developed by LIP (Laboratory of Instrumentation and Experimental Particle Physics) for ESA (European Space Agency), and includes location dependent surface composition, as well as user custom particle spectra as inputs.
We validated the model by comparing the LET (Linear Energy Transfer) spectrum obtained with LUNAIRE to measurements of the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) aboard the Lunar Reconnaissance Orbiter (LRO). Additionally, we compared the spectrum of secondary particles production with those of the HZETRN (High Charge and Energy Transport) code available through OLTARIS (On-Line Tool for the Assessment of Radiation in Space).
The results allow for a reconstructed GCR spectra that matches BadhwarO'Neill (BON) Galactic Cosmic Ray Model reference curves across species. We found the LET spectrum to be in good agreement with CRaTER data for both July 2009 (solar minimum available) and July 2015 (solar maximum available). Secondary particle fluxes also match HZETRN results for neutrons and protons but are not so according for electrons and gamma particles. This was attributed to differences in the physics processes of HZETRN comparing to Geant4.
These results show that LUNAIRE accurately characterizes the lunar radiation environment that can lead to better forecasts of, and safer missions. Ongoing work includes the evaluation against SEP events, the incorporation of complex topography geometries and validation against other mission results.
How to cite: Lima, B., Neves, T., Arruda, L., Gonçalves, P., Gomes, A., and Pinto, M.: LUNAIRE - LUNAr Ionising Radiation Environment , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-737, https://doi.org/10.5194/egusphere-egu26-737, 2026.
When the Moon was in the solar wind, Kaguya frequently observed ions originating from the Moon. To examine their statistical properties, we analyzed Kaguya low-energy particle data obtained from January 2008 to June 2009. These Moon-originating ions were mainly detected on the lunar far side, with energies ranging from 20 to 300 eV. At the time of their creation at or near the lunar surface, the ions are expected to have energies of only a few eV or less. Consequently, the ions observed by Kaguya are energized by a factor of 10 to 100. Time-of-flight (TOF) analyses indicate that these ions consist of C+, O+, Na+, Al+, K+, and Ar+. We found a pronounced asymmetry between the Northern and Southern Hemispheres in the detection rate of Moon-originating ions. These ions are concentrated mainly at high northern latitudes. To investigate the energization and asymmetric spatial distribution of Moon-originating ions, we perform test-particle simulations and discuss where and how the ions are energized and what produces the asymmetry.
How to cite: Lee, J., Kim, K.-H., Hong, Y., Baek, S.-M., Jin, H., and Lee, J.: Statistical Study of Moon-originating Ions in the Solar Wind, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8506, https://doi.org/10.5194/egusphere-egu26-8506, 2026.
Surface roughness is an effective parameter for mapping geomorphological units and for quantifying the topographic evolution of the Moon’s surface, as it records the effects of impact cratering, regolith processes, and geological modification [1,2]. It highlights surface features that are often difficult to detect in optical images and conventional digital elevation models (DEMs). Additionally, roughness at small spatial scales is valuable for assessing landing site hazards and for interpreting radar remote sensing observations. However, existing global lunar roughness maps are largely limited to ~10 m and longer baselines, thereby hindering spatially detailed studies of surface geology.
We present novel estimates of global surface roughness for the Moon at ~5 m length scales, determined from Lunar Orbiter Laser Altimeter (LOLA) echo pulse width measurements. In addition to measuring surface elevations from time-of-flight ranging, LOLA recorded the width of reflected laser pulses, which is sensitive to vertical variations within the illuminated footprint of ~5 m diameter. LOLA pulses reflected from the Moon’s surface are broadened relative to the transmitted pulses due to surface slopes and small-scale roughness. We determine small-scale roughness from the amount of pulse broadening, after correcting for factors such as beam divergence and curvature, observation geometry, the temporal decline in transmitted power, and receiver misalignment during polar and nightside crossings [3,4].
Roughness at sub-decameter scales (~5 m) reveals signatures of recent and ongoing surface processes on the Moon. The youngest impact craters, formed in the Copernican period, are distinctly rough, with interiors rougher than their ejecta blankets. The high-albedo swirl Reiner Gamma also appears unusually rough at these scales, despite lacking evident topographic expression, with on-swirl areas rougher than off-swirl. In the polar regions, permanently shadowed regions are smoother than nearby sunlit areas even on gentle slopes (<20°), suggesting potential for volatile preservation [5]. Among Artemis III candidate sites in the south pole, the Mons Mouton Plateau and Haworth are the smoothest and most favorable sites for rover navigation and extravehicular activities. Thus, our small-scale roughness map complements existing longer-baseline roughness products, captures topographic variability at spatial scales most relevant to upcoming surface missions, and provides new insight into recent modification of the lunar surface.
References: [1] Shepard M. K. et al. (2001) JGR, 106, 32777–32795. [2] Kreslavsky M. et al. (2013) Icarus, 226, 52-66. [3] Gardner C. S. (1992) IEEE Trans. Geosci. Remote Sens., 30, 1061–1072. [4] Neumann G. A. et al. (2003) GRL, 30(11). [5] Magaña L. O. et al. (2024) Planet. Sci. J., 5(2), 30.
How to cite: Christopher, H. and Ganesh, I.: Global Sub-Decameter-Scale Roughness of the Moon’s Surface, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15457, https://doi.org/10.5194/egusphere-egu26-15457, 2026.
As human lunar exploration advances through NASA’s Artemis mission and ambitions for a permanent lunar presence grow, understanding lunar regolith is increasingly important. Particle shape plays a pivotal role in governing the behaviour of granular materials, affecting regolith strength, angle of repose, packing density, and interactions with landing spacecraft. Quantitative characterization of lunar regolith particles is therefore essential for mission planning and for the development and validation of adequate simulants used in engineering studies and equipment testing.
Previous studies have therefore investigated various shape properties of lunar regolith samples and their corresponding simulants using both 2D and 3D techniques. While 2D approaches such as dynamic (DIA) and static image analysis (SIA) are simple and effective, they do not capture the full 3D geometry of particles and are sensitive to viewing orientation. In contrast, 3D approaches such as laser scanning or X-ray microcomputed tomography (µCT) provide high geometric accuracy but are time-intensive, laborious, and computationally demanding, resulting in a limited number of studies performing 3D shape characterization of lunar regolith simulants. More recently, 3D dynamic image analysis (3D-DIA) has emerged as an intermediate approach, approximating 3D particle geometry from multiple projections. However, only a few setups currently exist, and most rely on proprietary software, limiting transparency, reproducibility, and accessibility.
Furthermore, extracted shape properties are often analysed individually, overlooking the inherently multi-dimensional nature of particle morphology. Emerging quantitative frameworks, such as morphospaces, are therefore needed to comprehensively capture particle shape and enable systematic, holistic comparison across simulants.
To address the challenge of transparent and reproducible 3D shape characterization of granular particles, we present a novel, low-cost 3D-DIA setup paired with an open-source processing pipeline, which incorporates deep learning–based particle detection and a custom tracking algorithm. The accuracy of derived 3D particle shape descriptors is evaluated against high-resolution µCT scans. Building on the recent introduction of bivariate morphospaces for comprehensive particle shape characterization, we extend this framework by including intermediate-scale particle roundness, thereby establishing a trivariate morphospace that captures all shape properties of powder materials obtainable from imaging data. Distributional patterns within these morphospaces are captured using multi-dimensional Gaussian kernel density estimation (KDE), facilitating quantitative comparison between particle populations via density difference mapping. To further support quantitative assessment across simulants, we introduce the morphological richness (MRic) metric, which condenses the overall morphological diversity of a given simulant into a single scalar value.
To evaluate the proposed framework, 3D particle shape descriptors derived from the 3D-DIA setup were compared with reference µCT measurements. The results show strong agreement and substantial improvement over approximations obtained from single-projection approaches using 2D-DIA and 2D-SIA. Multi-dimensional KDE-based morphospace analysis of EAC-1A, JSC-2A, and NUW-LHT-5M reveals distinct differences in particle shape distributions, further quantified by the MRic metric. These findings demonstrate that the proposed approach provides a robust, reproducible, and scalable method for comprehensive characterization of lunar regolith simulant morphology, supporting the design of more representative simulants and enabling improved understanding of material behaviour in future lunar missions and surface operations.
How to cite: Müller, B., Shahsavari, M., Kollmer, J., Kounadi, O., and Sperl, M.: An Experimental 2D–3D Dynamic Image Analysis Framework for Particle Shape Characterization and Morphological Analysis of Lunar Regolith Simulants in Multi-Dimensional Morphospaces, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20616, https://doi.org/10.5194/egusphere-egu26-20616, 2026.
Posters on site: Fri, 8 May, 08:30–10:15 | Hall X4
The late accretion of exotic materials is significant in the study of the formation and evolution of the Earth and the Moon. The importance of platinum-group elements (PGEs) in tracking the late accretion stages of planetary formation has long been recognized. In previous studies, estimates of the flux of exotic materials added to the Moon have primarily been based on measurements of siderophile element concentrations in lunar regolith samples returned by the Apollo or Lunar missions. However, due to the analytical limitations at that time, only a few individual siderophile elements, such as Ni, Ir, Ge, Re, and Au, could be quantified. Among these elements, Ni is moderately siderophile, while Ge is moderately volatile, which means neither is the most ideal tracer for identifying the exotic materials in the moon. Advances in analytical techniques have significantly enhanced both the precision and accuracy of measurements for PGEs and Os isotopes. High-precision analytical techniques have established characteristic of PGEs patterns and Os isotope ratios in different meteorite types by ICPMS and TIMS. However, to date, no detailed study has been conducted on PGEs and Os isotopes in mature lunar soil.
The CE-5 lunar soil (CE-5LS) collection site is located in an area far from the Apollo and Luna mission regions, and previous studies have confirmed that the surface basalts in the CE-5 sampling area are more than 1 billion years younger than those in the Apollo and Lunar mission regions[1, 2]. This implies that the exotic material flux and composition within the CE-5LS may differ significantly from those in the Apollo lunar soil.
In this study, 1100 mg of CE-5LS samples were magnetically separated. And PGEs and Os isotopes were analyzed on the magnetic and non-magnetic fractions, respectively. The results indicate that the influx of exotic material at the CE-5 landing site amounted to approximately 0.8%, markedly lower than estimates based on the accumulation of exotic material in Apollo soil samples (1%–5%)[3-7]. Given that the accumulation of extraterrestrial material on the Moon correlates positively with the Moon's age, this conclusion is reasonable. The PGE patterns and Os isotope ratios in CE-5LS are consistent with those analysed in chondrites. Consequently, the exotic material accrated onto the Moon is predominantly chondrites.
Acknowledgment
The authors had the great honour of applying for and receiving approval to carry out studies on the CE-5 lunar samples allocated by the CNSA. This work was financially supported by the National Key Research and Development Project of China (2020YFA0714804).
Reference
[1] Che X. C., et al. (2021). Science 374:887.
[2] Li Q. L., et al. (2021). Nature 600:54.
[3] Ganapathy R., et al. (1970). Geochimica et Cosmochimica Acta Supplement 1:1117.
[4] Baedecker P. A., et al. (1974). Lunar and Planetary Science Conference Proceedings 2:1625-1643.
[5] Laul J. C., et al. (1974). Lunar and Planetary Science Conference Proceedings 2:1047-1066.
[6] Boynton W. V., et al. (1975). Lunar and Planetary Science Conference Proceedings 2:2241-2259.
[7] Higuchi H. and Morgan J. W. (1975). Lunar and Planetary Science Conference Proceedings 2:1625-1651.
How to cite: Wang, G., Zeng, Y., Lin, Y., and Xu, J.: PGEs and Re-Os in CE-5 Lunar Soil: Implications for Late Accretion to the Moon, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13113, https://doi.org/10.5194/egusphere-egu26-13113, 2026.
It is widely accepted that the Moon lost most of its volatiles during formation by a catastrophic impact and subsequent accretion from a hot debris disk.[1] However, analyses of primitive lunar samples (e.g., olivine-hosted melt inclusions) indicate that portions of the lunar silicate mantle (bulk silicate Moon; BSM) may retain significant amounts of volatiles.[2] A recent compilation [3] provides best estimates for BSM volatile abundances, including S, H, O, and C, with hydrogen showing the greatest variability. In parallel, remote sensing data reveal water ice deposits in permanently shadowed polar regions of the Moon, implying the presence of water reservoirs today.[4]
Despite these observations, the implications of a volatile-rich BSM for the Moon’s differentiation and resulting reservoirs (core-mantle-atmosphere) remain poorly explored. Here, we apply a state-of-the-art differentiation model developed in our lab [5] inspired by recent work [6, 7] that tracks volatile partitioning using experimental volatile solubility laws for silicate melt, metal, and gas. The model is benchmarked against proposed BSM volatile inventories.[3] We assess the impact of a range of mantle volatile contents on the composition of the Fe-dominated lunar core. We deduce plausible volatile abundances (in wt% of the core) of S = 0.4–1.1, H < 10-4; O ≈ 0.1, and C = 0.05–0.16. We further evaluate composition and mass of an atmosphere generated during lunar magma ocean degassing. Such an atmosphere is CO and H2-dominated, with total pressures of 0.5–6 bar, PH2O/PH2 ≈ 0.05 and PCO/PCO2 = 63.7–64.6. Our results provide new constraints on volatile redistribution during lunar differentiation and support a magmatic contribution to the formation of lunar polar ice.
1 Kato et al. 2015 Nature Communications (6) 7617, 2 Saal et al. 2008 Nature (454) 192-195, 3 McCubbin et al. 2023 Reviews in Mineralogy and Petrology (89) 729-786, 4 Li et al. 2018 PNAS (115) 8907-8912, 5 https://calcul-isto.cnrs-orleans.fr/apps/magworld_III/, 6 Gaillard et al., 2021 Space Science Reviews (217), 7 Gaillard et al., 2022 Earth and Planetary Science Letters (577) 117255
How to cite: Haupt, C. P., McCubbin, F. M., and Gaillard, F.: Consequences of a volatile-rich bulk silicate Moon for its core and transient atmosphere, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17808, https://doi.org/10.5194/egusphere-egu26-17808, 2026.
Impact craters are ubiquitous features on surfaces of planetary bodies in the inner Solar System. Impact cratering exposes subsurface materials, making them valuable for studying subsurface compositions of planetary bodies. The ~1.88 km diameter Lonar crater in India is a simple crater that formed by the impact of a chondritic impactor ~570 ka ago [1,2]. This is a well-preserved crater hosted entirely within the ~66 My old Deccan continental flood basalts, making it an ideal terrestrial analogue for craters on the basaltic surfaces of other planetary bodies like the Moon. We report geochemical and stable (δ88Sr) and radiogenic (87Sr/86Sr) Sr isotopic compositions of six target basalts and nine impact melt breccias sampled from the upper crater wall and the distal ejecta blanket [2,3]. Geochemical measurements were performed using an ICP-MS (Thermo Scientific iCAP RQ), while Sr isotopic compositions were measured using TIMS (Thermo Scientific Triton Plus) at the Centre for Earth Sciences, IISc, Bengaluru. The external reproducibility for δ88Sr measurements using an 84Sr-87Sr double-spike technique [4] was better than 0.033‰ (2SD) based on repeated analyses of NIST SRM-987 Sr standard (n=6).
The δ88Sr values of the Lonar crater rocks are the first such values reported for any impact crater; the δ88Sr values range from 0.256‰ to 0.305‰ for the target basalts (average = 0.278 ± 0.04‰ (2SD), n = 6) and from 0.113‰ to 0.288‰ for the impact melt breccias. The impactites are categorized into two groups: Group 1 (n=4) with δ88Sr values overlapping those of target basalts, and Group 2 (n=5), which exhibits lower δ88Sr values relative to the target basalts. The 87Sr/86Sr ratios of the impactites (0.707519-0.708139) are more radiogenic than the target basalt average of 0.706600 and are consistent with a 3-5 wt% contribution from the underlying granitic basement of Deccan lavas to the impact melt breccias [2,3]. After correcting for the contribution of the basement, the δ88Sr values of the impactites were used to model the extent and nature of kinetic isotope fractionation, employing the standard Rayleigh fractionation model using a Monte Carlo simulation. The absence of heavier δ⁸⁸Sr values in the impact melt breccias suggests that Lonar impactites predominantly reflect origin from vapour condensates. The primary vapour originated from complete volatilization of Sr from the target and projectile, yielding a δ⁸⁸Sr similar to Lonar basalts. Group 2 impact melt breccias likely contain a component formed through nearly complete (>99%) Sr condensation within the impact vapour plume. In contrast, Group 1 impact melt breccias may have originated from the impact ejecta blanket, reflecting no evidence of significant evaporative loss.
[1] Fredriksson, K., et al. (1973), Science 180.4088.
[2] Gupta, R. D., et al. (2017), GCA, 215.
[3] Chakrabarti, R., & Basu, A.R. (2006), EPSL 247.3-4.
[4] Ganguly, S., & Chakrabarti, R. (2022), JAAS, 37(10).
How to cite: Papola, G. S. and Chakrabarti, R.: Stable Sr Variations in Impactites of Lonar Impact Crater, India: A Terrestrial Analogue for Lunar Crustal Evolution , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-630, https://doi.org/10.5194/egusphere-egu26-630, 2026.
Reliable assessment of lunar surface engineering behavior requires regolith simulants that realistically capture both the mechanical response and impact-derived characteristics of natural lunar regolith. Although numerous lunar regolith simulants have been developed for geotechnical testing, most remain insufficient in reproducing the structure and mechanical role of impact products such as agglutinates and impact breccias, which dominate the load-bearing framework of lunar regolith. In this study, we establish a fabrication route for lunar regolith simulants that combines thermal processing of basalt-derived materials with glass-phase incorporation and subsequent mechanical crushing. Using this method, two simulant series, THIP-5 and THIP-6, are designed to represent regolith conditions at the Chang’e-5 nearside and Chang’e-6 farside landing regions, respectively. Systematic laboratory characterization demonstrates that the impact product simulant generated with 25 wt.% hollow glass beads reproduce key morphological and micromechanical features of natural lunar impact products. Comparisons of bulk scale properties further reveal that the synthesized simulants closely match their corresponding target soils across multiple physical and compositional metrics, including mineralogy, chemistry, grain-size characteristics, and density-related parameters. Furthermore, static angle of repose tests show that THIP-5 exhibits behavior comparable to established Chang’e-5 simulants, while experimental results from THIP-6 enable an estimation of the static angle of repose of the Chang’e-6 regolith at approximately 52.8°. The THIP simulant framework provides a physically grounded experimental basis for investigating lunar regolith mechanics, supporting the design of surface infrastructure, mobility systems, and future astronaut operations on the Moon.
How to cite: Luo, A., Cui, Y., and Nie, J.: Lunar regolith simulants incorporating impact product simulants for surface engineering and exploration applications, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2442, https://doi.org/10.5194/egusphere-egu26-2442, 2026.
The anorthite-dominated highlands and the basalt-dominated mare have been bombarded by solar radiation, cosmic rays, charged particles, comets, meteorites, and micrometeorites for over 4.5 billion years, resulting in space weathering at many scales and the collection of interplanetary matter. A majority of the finest fraction (<75 microns) of lunar regolith are endogenous materials: micro- to nano-sized crystalline fragments of the original materials, minerals shocked and amorphized by solar and cosmic radiation, vapor-deposited glass, impact splash, volcanic glass spheres. The exogenous materials include: micro- and nano-scale meteorites and extraterrestrial particles. Despite this conventional microscopy-derived knowledge of the nanoscale, the components of finest fractions of lunar regolith have always been challenging to study with IR and UV spectroscopy due to small grain size, and thermal and space weathering effects that often confound bulk spectra. In fact, until recently, spectroscopy on the individual components at scales of causality (nanometer level) was intractable.
We have applied vibrational electron energy-loss spectroscopy to six Apollo samples (three from highlands, three from mare) from four missions, each with differing space weathering maturities (Is/FeO). For highland samples: Apollo 62231 is mature (Is/FeO=91), 61141 sub-mature (56), 61221 immature (8.2). All mare samples are mature: 14259 (85), 15041 (95), and 79221 (80). Identified components in the regoliths include crystalline anorthite, amorphous CaAl2Si2O8(maskelynite) rims with/without iron nanoparticles (FeNPs), olivine, pyroxene, ilmenite, micrometeorites, and glass spheres. This method is employed by a special dedicated scanning transmission electron microscope that generates a monochromated ultrahigh energy resolution electron beam allowing Mid/near IR (MNIR) ‘aloof’ spectral analysis, akin to IR, albeit with a slightly poorer energy resolution, but a much higher spatial localization thanks to the sub-nm electron probe used here. Crystalline anorthite spectra reproduce positions of the five clusters of MNIR absorption peaks (217, 363, 548, 750, 976-1049 cm-1) at slightly lower resolution than FTIR. Loss of crystalline structure causes a split peak at ~1100 cm-1 to broaden, merge, and decrease in intensity. Also, the peak at ~550 cm-1 drops dramatically in intensity in more highly weathered samples. The addition of FeNPs within the amorphous material flattens, or attenuates, the spectra, leaving only the 1100 cm-1 peak. The MIR Christiansen Feature position appears to be affected by crystallinity, glass composition, and abundance of FeNPs at this scale. In the Visible and UV range, "impact" vibEELS collects spectra that document the color absorption changes associated with space weathering as the amount of FeNPs and vitrification increases. The shift towards a reddened slope observed in remote near-IR and UV of bulk samples, is also observed in individual particles that have more FeNPs. The vibEELS data also allows for the determination of the band gap, and therefore, the estimation of the dielectric constant of the weathered surface of regolith particles, which can be used to calculate lunar regolith properties relevant to interpretation of radar wavelengths.
VibEELS is exquisitely well suited for examination of lunar finest fraction and brings planetary events and materials mixed into this fraction into new focus and perspective.
How to cite: Livi, K., Ramasse, Q., Kepaptsoglou, D., Ramprasad, T., Cahill, J., McCanta, M., and Dyar, D.: Nanoscale Mid-IR to UV of Lunar Regolith Constituents Through Vibrational Electron Energy Loss Spectroscopy (vibEELS), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22192, https://doi.org/10.5194/egusphere-egu26-22192, 2026.
Pakepake_005 is a lunar fragmental breccia recovered from the Taklamakan Desert, Xinjiang, China. It exhibits a clastic breccia texture, in which mineral fragments and subordinate lithic clasts are cemented by matrix and impact glass. The dominant phases are plagioclase and pyroxene, whereas olivine is less abundant but widely distributed. Minor to accessory phases include ilmenite, chromite, troilite, phosphates, silica, baddeleyite, armalcolite, and Fe–Ni metal. Lithic clasts comprise impact-melt, plutonic, and basaltic components, as well as symplectites produced by breakdown of pyroxene.
Pyroxene clasts are predominantly subhedral to anhedral and range from ~0.1 to 1 mm in size. A subset exhibits fine clinopyroxene–orthopyroxene exsolution lamellae, with Mg# spanning 15.3–71.4 and locally well-developed Fe–Mg zoning. In contrast, some Fe-rich pyroxenes lack exsolution, are compositionally homogeneous, commonly fractured, and have Mg# values of 6.6–45.2. Some Fe-rich pyroxenes underwent breakdown reactions to form symplectites consisting of augite (Mg# = 30.7–35.5), fayalitic olivine, and quartz, accompanied by minor ilmenite and phosphate minerals. Mg-rich pyroxenes also lack exsolution, are comparatively homogeneous, and have Mg# values of 50.7–74.8.
Pyroxene compositions define two distinct populations on the Fe/(Fe+Mg)–Ti/(Ti+Cr) diagram, indicating multiple sources. The first group shows a positive correlation between Fe/(Fe+Mg) and Ti/(Ti+Cr), consistent with pyroxenes from very low-Ti (VLT) lunar basalts [1]. The second group is characterized by higher Mg# together with relatively elevated Ti/(Ti+Cr), consistent with magnesian pyroxenes crystallized from a more primitive melt. CI-chondrite-normalized REE patterns [2] further indicate that those pyroxenes record at least two sources.
In situ SHRIMP U–Pb geochronology of phosphates and baddeleyite from different components constrains two major events recorded by Pakepake_005. Phosphates hosted in the matrix and impact-derived lithic clasts yield an impact age of 3923 Ma, consistent with the Imbrium basin forming event around ~3.9 Ga[3]. In contrast, phosphates in symplectites and baddeleyite from a VLT clast yield an age of 3486 Ma, documenting a VLT magmatic episode. Taken together, these petrographic, mineral-chemical, and chronological constraints suggest that Pakepake_005 was sourced from an Imbrium-ejecta–related VLT basaltic unit, broadly analogous to basaltic materials exposed in the northern Mare Imbrium region (e.g., east of the Chang’e-3 landing site), where remote-sensing data indicate VLT compositions and yield model eruption ages of ~3.5 Ga for the associated basaltic unit [4].
Acknowledgments: This study was financially supported by National Key R&D Program of China from Ministry of Science and Technology of the People’s Republic of China grant no. 2022YFF0704905, the National Natural Science Foundation of China (NSFC) grant no. 42241107 and the Open Project for Innovative Platform of Meteoritical Research, Shanghai Science and Technology Museum.
[1] Robinson K. L. et al. (2012). Meteoritics & Planetary Science 47: 387–399.[2] Anders E. and Grevesse N. (1989). Geochimica et Cosmochimica Acta 53: 197–214.[3] Nemchin A. A. et al. (2021). Geochemistry 81: 125683.[4] Ji J. et al. (2022). Science Bulletin 67: 1544–1548.
How to cite: Yue, C., Che, X., Long, T., Wang, Z., Jin, M., Ding, X., Ma, Q., and Liu, D.: Mineralogical, Geochemical and Chronological Study of the lunar fragmental breccia Pakepake_005, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5708, https://doi.org/10.5194/egusphere-egu26-5708, 2026.
Mare Australe (47.77°S, 91.99°E) is a distinctive volcanic province (diameter ~1000km) at the eastern nearside and farside boundary of the Moon. The basalts of the region were considered a part of mare filling volcanism inside an ‘Australe Basin’ due to the circular arrangement of its 248 basaltic patches [1]. The proposed Australe Basin, however, lacks any discernible topographic signatures, a ring morphology, and a central positive Bouguer anomaly typically associated with the lunar impact basins. The results from the GRAIL mission and geological investigations revealed the presence of a ~880 km diameter impact structure in the northern part of Mare Australe, naming it the Australe North Basin (35.5°S, 96°E) [2, 3]. The Mare Australe basalts are dominantly emplaced outside this newly discovered Australe North Basin, which is perplexing. In this study, we carry out an extensive compositional investigation of the previously uncharacterized Australe region using hyperspectral data from the Moon Mineralogical Mapper (M3) onboard Chandrayaan-1. We investigate both mare and non-mare units in the region to understand their mineralogy in the given geological context. The spectral investigation reveals that despite widespread volcanism, the region lacks the presence of high-Ca pyroxene. Instead, the basalts are primarily composed of low to intermediate Ca-pyroxene in comparison to the rest of the lunar basalts, displaying their unique mineralogical signature. These findings provide new insights into the nature and origin of the atypical volcanism on the Moon in the Australe Region and highlight the distinct geological environment of Mare Australe responsible for the same. This study offers important implications for understanding lunar volcanic evolution and its relationship with impact processes.
[1] Whitford-Stark, J. L. (1979) LPSC X, 2975- 2994. [2] Neumann G. A. et al. (2015) Sci Adv. 1(9), e1500852. [3] Panwar N. and Srivastava N. (2024) Icarus, 408, 115841
How to cite: Panwar, N., Kapadia, T., and Srivastava, N.: Spectral Investigation of the Mare Australe Basalts: A Fresh look at the Atypical Volcanism on the Moon, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-956, https://doi.org/10.5194/egusphere-egu26-956, 2026.
Characterizing lunar surface mineralogy is essential for understanding crustal evolution, magma ocean differentiation, impact excavation processes, and identifying In-Situ Resource Utilization (ISRU) targets for future exploration. This study determines the mineralogical composition and crustal stratigraphy across four geologically distinct lunar terrains using Moon Mineralogy Mapper (M³) hyperspectral data: the Aristarchus plateau (volcanically complex), Dionysius crater (a pristine impact structure), the Malapert region (ancient highlands of the South Pole), and Leibnitz R (primordial anorthositic crust).
Level-2 M³ hyperspectral cubes (430-3000 nm, 140 m/pixel) [1] were processed through systematic workflows: destriping, photometric normalization, Minimum Noise Fraction (MNF) transform, Pixel Purity Index (PPI) endmember extraction, continuum removal, and Spectral Angle Mapper (SAM) classification. Spectral signatures were validated against RELAB laboratory spectra resampled to M³ resolution. Key mineral phases identified include anorthite, low-calcium pyroxene (LCP), high-calcium pyroxene (HCP), olivine, spinel-bearing assemblages, and ilmenite.
Aristarchus exhibits the highest mineralogical diversity [2], with anorthositic highland material, HCP- and LCP-bearing mafic units, and localized olivine signatures. Anorthosite absorption features (1.25 µm band depth) dominate the crater floor, pyroxene signatures characterize the ejecta blanket, and olivine (1 µm band depth) appears along crater rims. This heterogeneity reflects volcanic emplacement and deep impact excavation, offering diverse oxygen-rich and iron-bearing ISRU targets.
Dionysius (Mare Tranquillitatis) reveals systematic radial mineralogical zonation from HCP-dominated rim materials to LCP-enriched central exposures, indicating excavation through compositionally stratified crust. This vertical gradient constrains upper crustal HCP overlying lower crustal LCP layers [3,4], consistent with magma ocean crystallization models. Olivine and ilmenite detections suggest penetration to mafic lithologies, constraining crust-mantle differentiation.
Malapert (South Pole) is predominantly anorthositic, with isolated spinel-bearing outcrops (5% band depth at 2 µm) associated with uplifted crustal blocks. These exposures constrain deep crustal composition and early magma ocean differentiation. The area's abundant anorthosite and its location near permanently shadowed regions make it a key site for oxygen extraction and the establishment of polar exploration facilities.
Leibnitz R (far side) displays spectrally pure anorthositic composition, representing primordial crust formed during lunar magma ocean plagioclase flotation. Its compositional homogeneity provides a reference for early lunar differentiation and high-purity feedstock for ISRU oxygen production.
This study integrates hyperspectral mineralogy with surface morphology to constrain crustal architecture and geological evolution across diverse lunar environments. The methodology establishes a replicable framework for hyperspectral analysis applicable to future mission planning, linking fundamental crustal processes to ISRU resource assessment and advancing sustainable lunar exploration strategies.
References: [1] Green et al. (2011) JGR: Planets, 10.1029/2011JE003797; [2] Chevrel et al. (2009) Icarus, 10.1016/j.icarus.2008.08.005; [3] Moriarty & Pieters (2018) JGR, 10.1002/2017JE005364; [4] Wieczorek et al. (2013) Science, 10.1126/science.1231530
Acknowledgement: EU HORIZON-MSCA-2023-SE-01, Grant 101183089
How to cite: Guth, C., Mancini, F., Allemand, P., Salese, F., and Ori, G. G.: Mineralogical Diversity and Crustal Composition of Selected Lunar Regions Based on M³ Hyperspectral Analysis: Implications for ISRU and Future Exploration, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3498, https://doi.org/10.5194/egusphere-egu26-3498, 2026.
MAJIS is the Moons and Jupiter Imaging Spectrometer onboard ESA’s Jupiter Icy Moons Explorer (JUICE) mission. It covers the spectral range from 0.5 to 5.56 µm through two spectral channels: the VIS-NIR channel (0.495–2.35 µm) and the IR channel (2.28–5.56 µm), with up to 640 spectral samples per channel. The main scientific goals of MAJIS are to investigate the surface composition and physical properties of the Jovian icy satellites by detecting ices, salts, organics, and rocky materials [1].
The JUICE mission was launched in April 2023 and will arrive at Jupiter in July 2031. During the cruise phase, JUICE performed observations of the Moon and Earth thanks to a double flyby (Lunar-Earth Gravitational Assist, LEGA) in August 2024, reaching a minimum altitude of 750 km for the Moon and 6100 km for Earth. This provided a unique opportunity to validate MAJIS’s technical and scientific performance after launch [2, 3].
On the Moon, MAJIS observed equatorial regions in Mare Tranquillitatis, Mare Fecunditatis, and neighbouring highland terrains, confirming its capability to detect and map lunar mineralogical diversity and soil maturity [2, 4]. Here, we focus on regions including Duke Island and the Ruin Basin in Mare Tranquillitatis, and the Messier Crater rays in Mare Fecunditatis. Detections of glass, pyroxene and olivine in other locations are also discussed.
This work has been developed under the ASI-INAF agreement n. 2023-6-HH.0.
[1] Poulet et al., 2024, SSR. [2] Poulet et al., 2026, Ann. Geo., submitted. [3] Langevin et al., 2026, Ann. Geo., submitted. [4] Zambon et al., 2026, Ann. Geo., submitted.
How to cite: De Sanctis, M. C., Altieri, F., Zambon, F., Massa, G., Le Mouélic, S., Piccioni, G., Poulet, F., Langevin, Y., Royer, C., Tosi, F., Karatekin, O., and Mura, A.: Mineralogical diversity and soil maturity in the MAJIS/JUICE lunar spectral data , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22462, https://doi.org/10.5194/egusphere-egu26-22462, 2026.
The TILT-1, installed at the Observatory of Calern (Observatoire de la Côte d'Azur) was sucesfully tested during the Geminids meteor shower in December 2025. Recording of some tens of potential LIF, several of which being confrimed, was achieved.
How to cite: Delbo, M., Lognonne, P., Girard, P., Mauclert, N., Sheward, D., Avdellidou, C., Herrier, L., Parra, T., Rivet, J.-P., Mongellaz, B., Anfosso, N., Maeght, E., Grimaldi, D., Froissart, P.-Y., Saliby, C., Ferrero, A., and Angelini, M.: The Twin Impact Lunar Telescope network, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7444, https://doi.org/10.5194/egusphere-egu26-7444, 2026.
During the 2025 Geminids, which peaked between 2025-12-13 and 2025-12-14, the Moon was between 30-40% illuminated, with the radiant of the Geminid meteoroid stream on the unilluminated hemisphere of the Moon. This orbital geometry, coupled with the favourable observation conditions, prompted a global campaign to observe Lunar Impact Flashes (LIFs). As part of the commissioning phase of the TILT instrument (a dual 40 cm Newtonian telescope system based in Calern, France, built for coordinated LIF observations alongside lunar-based seismometers, see abstract EGU26-7444 for more detail), we took part in this observation campaign.
TILT operated for the totality of the observable period over these two nights, obtaining a total of 8.5 hours of LIF observations. Five hours of observation were performed on 2025-12-13, using two visible cameras (one ASI183MM, and one ASI174MM), and a further three and a half hours were performed on 2025-12-14, using one visible camera (ASI183MM) and one short-wave infrared camera (Ninox 640SU). From this data, we detected 56 events which could not be immediately rejected as false positives and were so far able to confirm nine of these events as true LIFs, through the LIF lasting more than one frame (4 events), and by observing the flashes in multiple simultaneous observations (5 events). While we are unable to confirm with certainty that these events were belonging to the Geminids (due to the constant presence of the sporadic background population), all the confirmed LIFs exhibited impact geometry compatible with the Geminid meteoroid stream. After performing photometric calibration of these events using stars observed at a similar airmass throughout the observations, we found that the confirmed events have magnitudes ranging between +7.5 and +10.4. These impacts are estimated to have formed craters ranging between 0.7 m and 1.7 m rim-to-rim diameter.
Preliminary results suggest a rate of impacts of 1.1 hr-1 for confirmed events, and 6.6 hr-1 events for all events. For the purposes of multi-messenger observations with lunar seismometers, confirmation of the events can be performed using the seismic signal of the impact, and therefore confirming the impacts occurrence based solely on LIF observations is not required. Hence, this observation campaign has demonstrated the importance of observing during high impact-rate streams, such as the Geminids, for the future operations of TILT.
How to cite: Sheward, D., Delbo, M., Froissart, P.-Y., Saliby, C., Rivet, J.-P., Lognonné, P., and Avdellidou, C.: Observations of the 2025 Geminid Lunar Impact Flashes with TILT, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12566, https://doi.org/10.5194/egusphere-egu26-12566, 2026.
DLR and ESA are jointly operating the Moon analogue facility LUNA in Cologne, Germany, to provide a venue for end-to-end testing of instruments, experiments, procedures and operations in a controlled, standardized environment. The facility consists of a large-scale testbed filled with mare regolith simulant EAC-1A, nominally to a depth of 60 cm, but extending to 3 m in the so-called deep-floor area (DFA), as well as a smaller dust lab filled to about 60 cm depth with the Lumina250 highland simulant. Both simulants have been characterized with a focus on mineralogical and geological properties, but for EAC-1A, lab data on shear-wave velocities as well as electric properties are also available. For both of these properties, compaction, which is in-situ unknown, plays an important role.
Here, we report on the first attempts of in-situ characterization of the elastic properties of EAC-1A in LUNA by 12 single-station ambient vibration measurements that were analysed in terms of the H/V spectral ratios. In addition to a peak at 0.76 Hz consistently observed at all locations that is related to local geology (sediment-bedrock interface at about 150 m depth), measurements in areas covered by the regolith simulants show additional high-frequency peaks between 12 and 55 Hz, dependent on regolith thickness. As the regolith thickness at each measurement location is known, the common trade-off between layer velocity and thickness in the inversion of the H/V peak frequency is resolved and measurements at different regolith thicknesses can be used to constrain the vertical velocity profile of EAC-1A. However, the task is complicated by strong surface topography as well as the structure of the DFA and buried exploration targets within, which could potentially result in 2D and 3D site effects for some measurement locations. Hence, careful data selection based on the directivity of the observed H/V peaks is performed. First results indicate very similar velocities for both mare and highland simulants, pointing to the dominant effect of granular texture as compared to chemical composition.
We compare fits to the data for different types of velocity laws and also discuss our results in light of the laboratory measurements as well as in comparison to in-situ data from the Moon.
How to cite: Knapmeyer-Endrun, B.: First seismic in-situ characterization of regolith simulants in LUNA, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19748, https://doi.org/10.5194/egusphere-egu26-19748, 2026.
Apollo seismic data have greatly advanced our understanding of the Moon’s internal structure and seismic activity, but they also contain many glitches produced by the harsh lunar environment. For example, around lunar sunrise and sunset, hundreds of anomalous signals are typically recorded within a few hours. Characterizing the waveforms, distribution patterns, and causes of these glitches is essential, as it can provide important references for reducing the occurrence of anomalous signals during the observation and suppressing their interference during the analysis, thereby offering useful guidance for the implementation and data processing of seismic observations in upcoming lunar missions. In this study, we combined deep learning with template matching to detect and catalog acceleration-related glitches in the Apollo seismic records. The resulting catalogs reveal clear temporal patterns that correlate with lunar diurnal and seasonal cycles. Glitches around lunar sunrise and sunset are likely driven by rapid temperature changes, while daytime glitches are linked to shading by nearby objects or to lunar eclipses. Notably, we also found eclipse-related glitches. Because the instrument temperature changes induced by lunar eclipses are more abrupt than those at sunrise and sunset, this issue should be taken into account in future lunar seismic observations. We also identify elliptically polarized glitches, which differ from the predominantly linear polarization reported for Martian glitches and merit further investigation. The glitch catalogs show substantially fewer glitches during the lunar night than during the day, offering practical guidance for optimizing observation windows. In addition, station-to-station differences in daytime glitch patterns underscore the strong influence of site location and instrument deployment on data quality, which is an important consideration for future lunar missions. In summary, this work compiles acceleration-related glitch catalogs from Apollo seismic data, clarifies how the lunar environment affects seismic observations, and provides useful references for optimizing observing strategies and instrument deployment in upcoming missions.
How to cite: Liu, X., Xiao, Z., and Li, J.: Acceleration-Related Glitch Patterns in Apollo Seismic Data and Implications for Future Lunar Seismic Observation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16218, https://doi.org/10.5194/egusphere-egu26-16218, 2026.
Thermal moonquakes are a series of repetitive seismic signals exhibiting nearly identical waveform patterns and amplitudes that occur periodically with the lunar diurnal cycle. India’s Chandrayaan-3 mission, which successfully landed in the south polar region of the Moon, deployed the Instrument for Lunar Seismic Activity (ILSA) to record ground accelerations at the landing site (69.37°S, 32.32°E) between August 24, 2023, and September 4, 2024. The instrument also monitored local surface temperatures, revealing extreme variations ranging from –20 °C to +60 °C.
After preliminary data processing, distinct thermal moonquakes were identified. The objective of this study is to analyze their frequency-dependent characteristics and investigate temperature-driven signatures. Based on waveform morphology, the thermal moonquakes are classified into three types: impulsive, intermediate, and emergent. Among these, emergent events are natural and occur due to the extension and contraction of lunar rocks, whereas the impulsive and intermediate events are caused by rover movement and other experiments conducted during the mission.
An additional focus of this research is to estimate the source locations of the thermal moonquakes using a chi-squared iterative single-station event-location algorithm. Assuming that seismic energy propagates along a one-dimensional path through a near-surface velocity model, we perform a grid search over latitude and longitude to identify the most probable source regions. Our results suggest that natural thermal moonquakes may originate from thermally induced stresses caused by large diurnal temperature variations in the lunar regolith, which reduce rock elasticity and lead to cracking and micro-fracturing.
The lunar south polar region remains one of the most intriguing yet least explored areas on the Moon. This study provides new insights into its near-surface mechanical behavior, offering a significant contribution toward understanding thermal stress-induced seismicity and the geophysical environment of the lunar south pole.
Keywords: Thermal moonquakes; Chandrayaan-3; ILSA; Lunar south pole; Thermal stress-induced seismicity; Single-station event location; Lunar regolith; Diurnal temperature variation.
How to cite: Dey, A. K., Biswas, R., Sandhu, K., and Kumar, P.: Thermal moonquakes at the lunar south pole: New evidence from Chandrayaan-3 ILSA observations, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-620, https://doi.org/10.5194/egusphere-egu26-620, 2026.
China's Lunar Exploration Program aims to deploy advanced seismometers on the lunar surface for detecting and characterizing moonquakes, essential for understanding the Moon's internal structure. Compared to conventional seismic geophones, nano‑g‑resolution MEMS accelerometers offer superior sensitivity, compact size, and low power consumption—key attributes for space instrumentation. This paper presents a capacitive MEMS accelerometer designed for next‑generation lunar seismometry. Its sensing element consists of a movable silicon proof mass suspended by micromachined beams, with distributed capacitive electrodes detecting minute displacements.
Innovating beyond traditional parallel‑plate designs, a corrugated electrode structure reduces the second‑order nonlinear coefficient by half and the third‑order coefficient by two‑thirds, improving linearity without compromising footprint or sensitivity. Furthermore, the device incorporates an electrostatic negative stiffness mechanism, successfully reducing the intrinsic resonant frequency to 122 Hz. The decrease in resonant frequency improves the mechanical gain of the seismometer, thereby enhancing the instrument's sensitivity. The design also improves pull‑in stability, extending the operational measurement range.
Comprehensive experimental characterization validates the device's performance:
- The fabricated short-period (SP) seismometer achieves a low noise floor of 7 ng/√Hz within the 0.5–3.5 Hz band, which is crucial for detecting faint seismic signals.
- It exhibits a broad linear measurement range of ±34 mg and a high open-loop dynamic range of 134 dB.
- The device provides a –3 dB bandwidth of 180 Hz, supporting a wide frequency response.
- Notably, its extreme miniaturization—with a MEMS die measuring only 5.2 mm × 6.5 mm and a mass under 20 milli-gram—makes it particularly suitable for weight-sensitive lunar missions.
This research has not only developed a high‑sensitivity MEMS sensor suitable for lunar seismology, but also holds significant potential for terrestrial geophysical applications such as precision seismic monitoring and oil‑gas exploration. The design provides a promising and robust technical pathway for the future development of high‑performance closed‑loop MEMS accelerometers.
Fig 1 The schematic view of the proposed MEMS accelerometer system
Fig 2 Noise performance of the proposed MEMS accelerometer in an open-loop configuration, in which the self-noise is the actual noise floor of the proposed device, with the elimination of the influence of Earth tremors.
How to cite: wei, X., du, C., wang, Q., wei, T., ouyang, H., wang, Q., and liu, H.: MEMS short-period chip-level seismometer for the next generation Lunar/Mars seismograph, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9059, https://doi.org/10.5194/egusphere-egu26-9059, 2026.
The All-Sky Electrostatic Analyzer (A-ESA) is a scientific payload designed for installation on a lunar rover, which will observe variations of the plasma environment on the Moon. Since the launch of the science payload project, the team from National Cheng Kung University (NCKU) have successfully completed the PDR, CDR, TRR, and PAR reviews. By the end of 2024, the team from NCKU delivered the A-ESA to the Taiwan Space Agency (TASA). In early 2025, the A-ESA was sent to the Lunar Outpost for integration testing. A-ESA consists of an electrostatic analyzer on top, while an MCP assembly, power supply units, and electronics are located underneath. A-ESA features entrance scanning deflectors and inner scanning deflectors. The entrance of A-ESA is electrically scanned within approximately 90° in the vertical direction, resulting in a hemispherical field of view (FOV). When A-ESA operates in observation mode, it divides the collection of scientific data into 8 sections horizontally and 6 sections vertically. By sweeping high voltage, it generates 16 different energy levels. As a result, A-ESA can measure the plasma distribution function and the energy of charged particles in a hemispherical space on the lunar surface.
How to cite: Chang, T.-F., Chiang, C.-Y., Cheng, Y.-R., Yen, T.-E., Tsai, S.-C., Chen, C.-T., Liu, P.-J., and Cheng, Y.-T.: Design and Development of an All-Sky Electrostatic Analyzer, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18513, https://doi.org/10.5194/egusphere-egu26-18513, 2026.
Introduction and heritage
LUNINA is a compact, durable, and location‑independent node that provides accurate navigation and communication services on the Moon. Based on the FMI led ESA’s MiniPINS/LINS project heritage, each LUNINA unit operates autonomously nominally with RHU‑assisted thermal control, solar power, and batteries. RTG-unit option is also available. Deployed individually or as a network, LUNINA nodes enables precise positioning, robust data relay, and continuous operations, enabling and supporting the scientific missions on Moon surface and orbital missions.
Future Lunar science and missions requires dependable surface infrastructure for positioning and communication (data etc.). While future Lunar constellations will provide space segment navigation, surface users will face line‑of‑sight constraints, topographic shadowing etc. obstacles, and Lunar thermal extremes. LUNINA addresses these challenges with a drop‑and‑forget node that include navigation aid option and provides local data relay for science operations.
Figure: LUNINA nodes on the Lunar surface. Network of LUNINA's form an Earth-like mobile communication grid that supports both human and robotic Lunar exploration.
Surface operations that support the Lunar science
Accurate positioning supports the scientific operations, and it is required to achieve requirements posed by each Lunar mission goals. Nodes establish a resilient, low‑latency link between e.g. sensors/instruments, rovers, habitats, and orbiters. This LUNINA link capability and feature supports high efficiency measurements (e.g. done by multiple individual dust/plasma, thermal, environmental monitoring stations) and provides a 24/7 operating safety and communication channel for EVA operations as well. RHU‑assisted LUNINA thermal control maintains electronics safe through the Lunar night, reducing data loss and enabling long time‑series measurements and observations essential for understanding e.g. Lunar regolith thermophysics, exosphere variability, and electrostatic dust rising practically in all possible locations on Moon where at least some Sun light is present for solar panels. If node is equiped with optional RTG-unit providing the required power, then node is location-independent. In addition to this, strategic placement on hills or crater rims extends line‑of‑sight coverage into otherwise inaccessible terrain, complementing the Lunar Communications and Navigation Services (LCNS) space segment when available. We have identified following main science use cases for LUNINA:
- Geophysics: seismic science instrumentation as a piggy-back of LUNINA node. Delivery of the observation telemetry for crustal structure science and impact monitoring.
- Regolith and environment: LUNINA node assisting the thermal probes and permittivity sensors with nighttime power/thermal survivability in heat flow and volatile behaviour research.
- Dust–plasma interactions: electric field, plasma, and dust sensors included as a piggy-back at multiple LUNINA nodes to resolve charging and dust rising dynamics.
- Resources search and identification: navigation and data relay assist for mapping of the terrain that are in shadowed regions from Moon base and/or main lander.
Conclusions
LUNINA provides practically the nonstop navigation and communications base infrastructure that Lunar science needs and it is easy to scale with additional nodes. By enabling precise positioning, robust data relay, and night‑survivable operations, LUNINA contributes to the achieving of Lunar scientific benefits and results and supports both robotic and human Lunar exploration.
How to cite: Haukka, H., Kestilä, A., Harri, A.-M., Genzer, M., Nyman, L., Koskimaa, P., and Kivekäs, J.: LUNINA: In‑situ Navigation and Communication Infrastructure for Lunar Science, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5115, https://doi.org/10.5194/egusphere-egu26-5115, 2026.
LunarLeaper is a robotic mission concept aimed at advancing our understanding of the Moon’s subsurface structure and geological evolution through the exploration of volcanic pits—steep-walled collapse features on the lunar surface. Orbital observations indicate that some of these pits may provide access to extensive subsurface lava tube systems. However, such interpretations are limited by spatial resolution and viewing geometry, and only an in-situ surface mission can unambiguously confirm and characterize the relationship between pits and underlying caves. We propose the use of a legged robotic platform to deploy geophysical instrumentation to the rim of a lunar pit on the near side of the Moon. From this vantage point, the mission will confirm the presence of a lava tube, constrain its geometry, and employ imaging and spectrometric measurements to reconstruct the volcanic history of the pit and its surrounding terrain.
The baseline payload for LunarLeaper consists of a camera system, a ground-penetrating radar, a gravimeter, and a spectrometer. We report the current status of payload accommodation on the robotic platform:
- The camera requirements for the mission can be met by an COTS camera system previously used as engineering cameras for ESA spacecraft, such as BepiColombo.
- We have developed a compact, PCB-based antenna system for the ground-penetrating radar that can be fully integrated beneath the robot body.
- Forward modelling of the expected gravimetric signal, combined with a preliminary noise budget that accounts for instrument tilt, shows that the sensitivity of the HERA-heritage gravimeter exceeds mission requirements by approximately an order of magnitude.
- Measurements with the Fabry-Perot spectrometer have been demonstrated against several mineralogical compositions.
- A preliminary concept of operations demonstrates that payload operation and data acquisition are compatible with overall mission constraints, specifically the mission duration of less than one lunar day.
Together, these results demonstrate that the combined geophysical and imaging payload suite can be accommodated on a small robotic platform, as currently being developed by the Robotic Systems Lab at ETH Zürich.
How to cite: Stähler, S. C., Mittelholz, A., Bickel, V. T., Cocheril, A., Fuhrer, A., Ghirotto, A., Grott, M., Hamran, S.-E., Hirzel, N., Isler, J., Karatekin, O., Luginbühl, Y., and Ritter, B.: LunarLeaper - Exploring Lunar Lava Tubes , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11531, https://doi.org/10.5194/egusphere-egu26-11531, 2026.
The Moon is a unique and accessible target that hosts a distinctive space environment. It provides an opportunity to investigate fundamental physics associated with interactions with the undisturbed solar wind, magnetosheath, and magnetosphere. During disturbed space weather events, the lunar environment is influenced by hot plasma within the coronal mass ejections or high-energy particles such as solar energetic particles or cosmic rays. In the absence of an intrinsic magnetic field and a collisional atmosphere, the solar wind directly impacts the lunar surface, resulting in a plasma–regolith interaction, the physics of which remains poorly explored.
The interaction also sputters surface volatiles, producing the exosphere, a fragile gaseous environment surrounding the Moon. Space plasma may also contribute to the formation of surficial water, which can subsequently be released into the exosphere or space by meteoroid impacts. However, direct observational evidence for the production, circulation, and accumulation of such species remains highly limited. In addition, the Moon has localized magnetic anomalies that modify the incident plasma flow and, consequently, the near-surface environment. These disturbances are known as mini-magnetospheres, the smallest magnetospheres known. Local disturbances from environmental changes (electromagnetic fields, illumination, and their temporal variations) can induce significant dust lofting. Lunar dust poses a major hazard to human and robotic explorers. It is adhesive, potentially toxic, and easily mobilized. Dust particles can easily infiltrate electronics systems and spacesuits, and are significantly influenced by near-surface electric and magnetic fields. Furthermore, since the beginning of the space age, the lunar environment has been increasingly altered by human activities. Planned or ongoing exploration is expected to accelerate this anthropogenic modification. Quantifying the lunar environment is therefore urgently required to distinguish between its (near-)pristine state and its altered conditions on a decadal time scale.
In this presentation, we provide an overview of the multidomain physical processes—both natural and anthropogenic— that occur at the lunar surface in the context of future lunar surface missions. We identify key open scientific questions concerning the lunar space environment and outline the measurements required to address them. These measurements are considered within the framework of the European scientific payload package concept, AstroLEAP (Lunar Environment Analysis Package), which is under study by ESA and the science community.
How to cite: Futaana, Y., Dandouras, I., Fröhlich, P., Genzer, M., Grison, B., Kestilä, A., Pontoni, A., Ranvier, S., Loewe, J. L., Nyman, L., Vorburger, A., Daniel, L. N., Hager, P., McDonald, F., and Cipriani, F. and the AstroLEAP Facility Definition Team and AstroLEAP Study Team: Interdisciplinary exploration science enabled by lunar landers: AstroLEAP sciences, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19727, https://doi.org/10.5194/egusphere-egu26-19727, 2026.
The Moon is thought to have solidified from a global lunar magma ocean (LMO) through fractional crystallization. Well-documented hemispheric asymmetries in topography, crustal thickness, surface abundances of radiogenic elements, and volcanic history suggest that the nearside and farside underwent distinct evolutionary pathways. These differences likely reflect variations in the deep interior, particularly in the distribution of radiogenic heat-producing elements (HPEs) capable of sustaining long-lived temperature contrasts. However, direct geophysical evidence for such a dichotomy has been limited. A recent study based on tidal response by Park et al. (2025) reveals a 2-3% difference in shear modulus between the nearside and farside mantle, implying that the nearside mantle remains ~200 K warmer today. Similarly, He et al. (2025), using Chang’e-6 farside basalt samples combined with remote-sensing-based geochemical modeling, report farside mantle temperatures at least ~100°C cooler than those of the nearside. In this study, we employ numerical modeling to investigate whether a hemispheric thermal contrast of several hundred kelvins in the lunar mantle can persist throughout lunar history and to assess how degree-1 mantle convection and HPE distributions influence the maintenance of this dichotomy. We further explore the role of dense ilmenite-bearing cumulates (IBCs), initially crystallized beneath the crust during the final stages of LMO solidification, and later overturned and settled near the core-mantle boundary due to gravitational instability, to shape the Moon’s long-term thermochemical and dynamical evolution.
How to cite: Kar, P. and Li, M.: Hemispheric Thermal Dichotomy in the Lunar Mantle, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-860, https://doi.org/10.5194/egusphere-egu26-860, 2026.
Accurate knowledge of the lunar gravitational field is essential for lunar exploration, for instance, for gravity predictions at prospective landing sites, for inertial navigation or to establish a physically meaningful height system. This contribution presents a new suite of Lunar Gravitational Maps 2026 (LGM2026). LGM2026 is sampled at the resolution of 128 pixels per degree (~250 m at the equator) and surpasses LGM2011, the most detailed lunar surface gravitational model to date, by a factor of ~6. The 250-m resolution was reached by combining long-wavelength gravity observed by the GRAIL satellites (scales up to 11 km at the equator) with short-scale gravity inferred from LRO and Kaguya topography (scales from 11 km to 250 m). To make the modelling of short-scale signals realistic, LGM2026 relies on a 3D crustal density model as opposed to the constant-density assumption of LGM2011. LGM2026 depicts (i) the gravitational potential (useful for studying gravity-driven mass movements or flow direction of fluids), (ii) the full gravitational vector (gravity predictions at landing sites, inertial navigation, verification of accelerometer readings) and (iii) the full gravitational tensor (upward/downward continuation of the potential and vector data, spacecraft navigation). The maps shows the gravitational field at the lunar surface and on a sphere of the radius 1749 km passing outside of all masses. As a by-product, LGM2026 was converted into a series of external spherical harmonics up to degree 11,519. The purpose of LGM2026 is to provide a high-resolution gravitational model for applications that are sensitive to the variations of the lunar gravitational field such as gravity predictions at landing sites or inertial navigation. Given that the short-scale signals are derived from the topography instead of gravity observations, LGM2026 must not be geophysically or geologically interpreted at scales smaller than 11 km. The accuracy of LGM2026 is estimated to 2 mGal in terms of the gravitational vector. All LGM2026 maps use the principal axes coordinate system. The release of LGM2026 is scheduled to mid-2026. This work was funded by the EU NextGenerationEU through the Recovery and Resilience Plan for Slovakia under the project No. 09I03-03-V04-00273.
How to cite: Bucha, B.: 250-m resolution lunar gravitational maps from gravity observed by satellites and gravity modelled from topography and 3D crustal density, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6331, https://doi.org/10.5194/egusphere-egu26-6331, 2026.
Lava tubes are subsurface volcanic conduits formed during effusive basaltic eruptions and are increasingly recognized as key targets for planetary exploration. On the Moon, orbital remote sensing imagery has revealed numerous collapse pits suggesting the presence of subsurface lava tube systems. These structures are of high scientific and exploration interest, as they may provide stable thermal environments, effective radiation shielding, and protection from impact hazards. However, the geophysical characterization of lunar lava tubes remains challenging, as current low-resolution orbital remote sensing techniques offer limited insight into their three-dimensional geometry, internal structure, spatial continuity and, in most cases, even their existence.
As future missions plan to deploy surface-based geophysical instruments, there is a growing need for robust and transferable integrated strategies to characterize subsurface lava tubes. Terrestrial lava tubes provide essential analogues for developing and validating such approaches, yet most existing studies rely on single geophysical techniques, limiting the completeness of subsurface interpretations.
Here, we present a comprehensive multi-method geophysical investigation of the lava tube “Cueva de Los Naturalistas” in the UNESCO Geopark of Lanzarote (Canary Islands), a well-established analogue for lunar volcanic terrains due to its basaltic composition, recent volcanic history and well-preserved lava tube system. We have conducted high-resolution, profile-based, active and passive seismic surveys coupled with magnetic and gravity investigations to image and characterize the subsurface geometry of the lava tube. Both passive and active seismic analyses reveal anomalous behaviour above the cavity, which strongly correlates with a negative magnetic and gravity anomaly. Joint 2D magnetic & gravity inverse modelling and 3D structural modal analysis of the roof of the lava tube allow us to constrain the tube’s location, dimensions and internal structure, highlighting the complementarity and suitability of the methods used and reducing ambiguities inherent in single-technique approaches.
Our results demonstrate the effectiveness of integrated seismic, magnetic and gravity surveying for lava tube characterization and provide a methodological strategy that can be adapted to future robotic and human missions on our natural satellite. This study contributes to closing a critical gap in our ability to assess subsurface cavities on the Moon and other planetary bodies.
How to cite: Ghirotto, A., Barone, I., Santoro De Vico, F., Melchiori, G., Zunino, A., Armadillo, E., Mittelholz, A., Sauro, F., and Massironi, M.: Seismic, magnetic and gravity investigations of Lunar lava tubes: An Earth-analogue case study from Lanzarote island (Spain), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11341, https://doi.org/10.5194/egusphere-egu26-11341, 2026.
With the advancement of deep space exploration, conducting electromagnetic (EM) sounding on the Moon is of great significance for investigating the lunar internal structure and the surface EM environment. Since the Moon lacks a global dipole magnetic field and is directly exposed to complex solar wind and Earth's magnetotail environments, clarifying its time-domain response mechanisms to external magnetic perturbations is a prerequisite for lunar surface EM exploration.
This study establishes a homogeneous spherical model to simulate the lunar electromagnetic response to disturbances in the interplanetary magnetic field. By deriving analytical solutions for electromagnetic fields under step excitation (simulating a 10 nT abrupt change in the solar wind), the transient response characteristics for lunar internal electrical conductivities in the range of 10-5 ~10-7S/m are quantitatively analyzed.
The simulation results reveal distinct induction mechanisms:(1) The penetration of the magnetic field is governed by the skin effect. Higher conductivity leads to a stronger shielding effect and a longer rise time to reach the steady state, whereas lower conductivity allows for faster magnetic propagation. (2) The induced electric field exhibits a transient response, with its magnitude inversely proportional to conductivity. Lower conductivity results in a higher instantaneous peak electric field but a faster decay, while higher conductivity suppresses the peak amplitude but extends the signal duration. (3) The induced electric field displays a toroidal symmetry along the latitudes, reaching its maximum at the lunar equator and zero at the poles, with no vertical component.
These findings indicate that electric field detection is particularly suitable for capturing high-frequency transient variations. The derived relationships between signal bandwidth, field intensity, and conductivity provide a theoretical reference for future lunar electromagnetic exploration.
How to cite: Zhang, W., Wang, Z., and Liu, Z.: Time-Domain Simulation and Transient Characteristics of Induced Electromagnetic Fields for Lunar Deep Interior Sounding, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3527, https://doi.org/10.5194/egusphere-egu26-3527, 2026.
Some lunar crustal magnetic anomalies are associated with albedo markings known as swirls; however, the processes governing their formation remain unclear. In this study, we focus on Reiner Gamma, a well-studied lunar anomaly and a key site for investigating the relationship between albedo patterns and magnetic anomalies. We perform test-particle simulations to examine how the Reiner Gamma swirl interacts with the local magnetic field, employing incident solar wind particles with energies of 0.5–1.0 keV and both line and disk magnetization models. The simulated magnetic fields are comparable to observations from previous lunar orbiters at altitudes of approximately 20 km and 40 km. Their maximum and minimum intensities, corresponding respectively to bright lobes and dark cusps on the lunar surface, align with the optical albedo patterns observed at Reiner Gamma. Our simulations show that the reflection area of solar wind particles above Reiner Gamma increases as the incident solar wind energy decreases. In the bright lobes, solar wind particle reflection exhibits a clear dependence on strong horizontal magnetic fields and dominant perpendicular energies. In contrast, reflection in the cusps is less definitive, being additionally governed by the interplay between relative perpendicular energy and magnetic configuration. We discuss the necessary conditions under which incident solar wind particles are absorbed at the surface or reflected above Reiner Gamma.
How to cite: Hong, Y., Kim, K.-H., Lee, J., Jin, H., and Baek, S.-M.: Interaction Between Solar Wind Particles and the Reiner Gamma Magnetic Anomaly: Observations and Test-Particle Simulations, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8775, https://doi.org/10.5194/egusphere-egu26-8775, 2026.
Lunar magnetic anomalies (LMAs) show a curious ability to reflect the high velocity ions (~400 km/s) of the solar wind, an effect of interest for manned missions. As it stands, current work in this area has focused primarily on simulation efforts supported by spacecraft data. There is a pressing need to better understand the structure of the miniature-magnetosphere system over a wide range of solar wind parameters if human missions come to rely on this shielding effect. To better target the fundamental physics of the miniature-magnetosphere, we propose an approach using a subscale experiment.
To investigate the basic physics and scaling parameters of the miniature-magnetosphere in a controlled setting, we constructed an experiment capable of recreating this plasma interaction at the laboratory scale. Specifically, we wish to investigate the magnitude, location, and thickness of the repelling electric field and how these parameters are influenced by the simulated solar wind.
A picture of the experiment in operation can be seen in [FIG. 1]. The simulated solar wind is created using an RF discharge and a DC voltage across two molybdenum grids. The resulting ion beam is neutralized by a hollow cathode mounted in the test chamber. The solar wind impacts the experiment assembly consisting of a Garolite (G-10) sheet acting as the lunar surface, a neodymium magnet beneath the surface mimicking the LMA, and a 3-axis translation stage actuating the probes. The entire platform can rotate ≤30° to simulate different solar wind incidence angles.
Emissive and Langmuir probes were chosen as diagnostics. The first measures plasma potential while operating in half-wave AC heating mode. The second measures ion density, electron temperature, and plasma potential. Initial results only report the ion saturation current which scales linearly with density and the root of the electron temperature. The scaling is important because spacecraft data shows elevated electron temperatures produced in the mini-magnetosphere.
The experiment is supported by 3D particle in cell (PIC) simulations to bridge the gap between experimental and lunar length scales. The two work in tandem to inform one another to better isolate the driving principles of the system.
Initial results from the emissive probe [FIG. 2] show a peak plasma potential of ~200 V directly above the magnet. This value monotonically decreases with distance to the magnet which is consistent with an outward electric field being established. The map of ion saturation current [FIG. 3] is not fully complete at the time of submission but does further corroborate the formation of an ion cavity surrounded by a higher density barrier region.
Visual observations of the plasma show an asymmetry across the magnetic axis that is consistent with the 3D PIC model. This “stretching” of the magnetosphere in one direction is consistent with an drift.
Complete 3-D maps of the density, potential, and temperature of the plasma will be ready by the conference date. A parametric investigation of various solar wind input conditions will also be conducted.
How to cite: Rae, P., Sharma, A., and Little, J.: Subscale Experiment for Investigating Lunar Magnetospheres, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15644, https://doi.org/10.5194/egusphere-egu26-15644, 2026.
As commercial and governmental interest in lunar resource utilization intensifies, helium-3 mining has re-emerged as a frequently cited motivation for sustained human and robotic activity on the Moon. Helium-3 is a rare isotope with applications in neutron detection (e.g., national security, medical imaging), quantum computing, and as a proposed fuel for advanced nuclear fusion concepts. However, the expected low concentrations of helium-3 in the lunar regolith raises significant questions regarding the environmental consequences of its extraction at any meaningful scale.
Analyses of samples returned by the Apollo and Chang’e missions indicate that helium-3 is present in the lunar regolith at concentrations of only a few parts per billion. Because it is implanted by the solar wind, helium-3 is concentrated primarily in the uppermost centimeters of the regolith, with abundances decreasing exponentially with depth. As a result, any plausible extraction architecture must process extremely large volumes of regolith to recover modest quantities of helium-3. Proposed concepts range from shallow surface scraping to excavation of regolith to depths of up to several meters, implying disturbance over vast surface areas.
In this work, I model the spatial extent of helium-3 mining required to meet a range of plausible future helium-3 demand scenarios. These scenarios encompass continued use in neutron detection technologies, emerging quantum computing architectures, and speculative deuterium–helium-3 (D-He3) fusion energy systems.
The results demonstrate that while neutron detection and other low-demand applications require comparatively limited surface disturbance, demand from quantum computing already implies mining areas extending over tens to hundreds of square kilometers. Although substantially smaller than fusion-driven scenarios—which imply surface areas several orders of magnitude larger—quantum computing demand alone would generate surface disturbances which could be detectable by Earth-based observers using mass-market telescopes, binoculars, or consumer-grade imaging systems. Fusion demand would therefore overwhelmingly dominate the ultimate spatial footprint of helium-3 extraction, but non-fusion applications cannot be considered environmentally negligible.
Beyond the scale of disturbance, the environmental consequences of proposed extraction methods remain poorly constrained. Many concepts rely on mechanical agitation, excavation, or high-temperature processing of regolith, all of which may alter grain size distributions, maturity, and optical properties of the lunar surface. If mining activities produce a persistent change in surface albedo or spectral reflectance, large helium-3 mining fields could become visible from Earth. Under fusion-driven demand scenarios, such alterations could plausibly render mining regions visible to the naked eye, raising scientific, cultural, and policy concerns.
Given the extremely slow rates of natural weathering and regolith gardening on the Moon, any anthropogenic surface modification associated with helium-3 mining would persist for timescales well beyond humans. I conclude that targeted laboratory experiments, modeling studies, in situ measurements, and independent monitoring of proposed helium-3 extraction attempts are urgently needed to constrain the environmental impacts of helium-3 mining. Until such impacts are better understood, a precautionary approach to large-scale lunar helium-3 mining is warranted.
How to cite: Timpe, M.: Projected Environmental Impacts of Helium-3 Mining on the Lunar Surface, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18687, https://doi.org/10.5194/egusphere-egu26-18687, 2026.
Posters virtual: Mon, 4 May, 14:00–18:00 | vPoster spot 4
EGU26-7948 | ECS | Posters virtual | VPS27
Prototype Design for a Lunar Lander High Resolution Stereo CameraMon, 04 May, 14:03–14:06 (CEST) vPoster spot 4
Terrestrial exploration with the help of rovers typically employs traditional stereo cameras, relying on binocular optical designs with large, bulky, and often moving parts. The stereo camera design concept presented in this study was developed and built using commercial off-the-shelf (COTS) components, allowing for rapid-prototyping, cost-effective testing, and performance evaluation under simulated mission conditions. An innovative use of four-mirror optical configuration and a monochrome CMOS sensor introduces a novel approach to achieve high resolution stereo imaging, while maintaining low power consumption and space requirements suitable for compact lander missions. By utilizing a single-detector stereo vision, the camera system can effectively create 3D reconstructions of observed objects with a spatial resolution of 54 μm per pixel, and depth resolution of <1 mm per pixel with the stereo baseline length of 116 mm, an instantaneous field of view of 601 μrad per pixel. The optical performance was validated with experiments such as the resolution and shape measurement test. The scientific applicability was demonstrated by extracting the static angle of repose of regolith simulants EAC-1A and NU-LHT-2M, as well as the relative surface albedo through a photometric stereo method, providing deeper understanding into the physical and optical properties of lunar regolith analogues. The presented camera design offers a balance between performance with compactness, addressing challenges faced by conventional stereo cameras such as baseline constraints, environmental exposure, and computational efficiency. Further design limitations and stereo matching inaccuracies were identified during testing and characterisation. The stereo camera developed in this study demonstrates capabilities for high-resolution, in-situ lunar surface analysis based on regolith characterization and contributes to an in-depth understanding of lunar regolith properties by close-range scientific analysis of its geo-mechanical behaviour.
How to cite: Chauhan, S. C., Jaumann, R., Grott, M., and Althaus, C.: Prototype Design for a Lunar Lander High Resolution Stereo Camera, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7948, https://doi.org/10.5194/egusphere-egu26-7948, 2026.
Posters virtual: Thu, 7 May, 14:00–18:00 | vPoster spot 4
EGU26-23186 | Posters virtual | VPS28
Water ice sublimation and O-H isotopic fractionation in terrestrial and extraterrestrial environments: new insights gained from numerical modelling and laboratory experimentsThu, 07 May, 14:21–14:24 (CEST) vPoster spot 4
Stable isotopes of oxygen and hydrogen are a powerful multipurpose tool widely used across multiple disciplines in Earth and Planetary sciences. In hydrology, δ18O and δ2H in the water molecule are commonly used in stream water source apportionment and transit time analyses. In paleoclimate research, ice core water isotope records are used as a temperature proxy, documenting past climate variability over hundreds of thousands of years. Oxygen and hydrogen isotopes are also versatile fingerprints for retracing the formation of planets and other celestial bodies.
These examples should not obscure the fact that many unknowns and uncertainties remain inherent to the use of stable isotopes of O and H as tracers and fingerprints of processes in terrestrial and extra-terrestrial environments. To this date, only a few experimental studies have investigated water ice sublimation rates and the effect of isotopic fractionation processes – notably on water ice under lunar environmental conditions.
Here we present results from a combined experimental and modelling approach. With an instrumental set-up developed at LIST, we simulate the sublimation of water ice under extreme environmental conditions (very high vacuum and/or very low temperatures) with the goal of exploring O-H isotopic fractionation processes in both (extreme) terrestrial and extraterrestrial environments. An understanding of these processes is necessary for interpreting the isotope signatures of water in planetary exploration missions, such as ESA’s PROSPECT project for lunar exploration, and in terrestrial hydrology of cold regions.
The current experimental setup consists of a sublimation chamber capable of operating at pressures down to 10⁻⁶ Pa and temperatures as low as 110 K, with high stability and control over sublimation conditions. The system can simulate controlled environments for the phase transition of water (ice-vapor), isotopic fractionation, and the movement of water vapor across different phases of the experimental run. This includes transferring gas to a series of parallel cold traps, analyzing isotopic content using laser spectroscopy.
We have developed a stochastic lagrangian numerical model to verify the existing theories of phase transition, diffusion, and O-H isotopic fractionation based on the Langevin equation. The model allows for sublimation, diffusive transport, and condensation of water and its isotopes through an isothermal domain representing the volume of the experimental prototype. Lagrangian models are highly adaptive for handling complex boundary conditions and well-suited for solving fluid mechanics problems with various types of particles.
A sensitivity analysis of the model using different sublimation temperatures shows consistent results with our experimental data. Results obtained from the dual isotope analysis (δ¹⁸O and δ²H) of ice samples obtained from Greenland Summit Precipitation (GRESP) and Antarctica snow show trends consistent with theoretical predictions and meteoric water line, suggesting that the setup is operating reliably. Observed deviations in the isotopic compositions indicate influences from environmental variables such as humidity, pointing towards the need for tighter control and validation. Our experimental set-up lays a foundation for further investigations into the problems of fast diffusion, non-equilibrium thermodynamics, and the isotopic signature of water.
How to cite: Kumawat, M., Barnich, F., Pfister, L., Zehe, E., and Hadler, K.: Water ice sublimation and O-H isotopic fractionation in terrestrial and extraterrestrial environments: new insights gained from numerical modelling and laboratory experiments, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-23186, https://doi.org/10.5194/egusphere-egu26-23186, 2026.
