Meteorite falls can occur at any given place on Earth, and instrument observations of their fireballs can help constrain search areas to recover freshly fallen fragments. Rapid recovery is essential in European field settings, where exposure to soil, moisture, and vegetation can quickly affect meteorite preservation. Drone-assisted aerial surveys of strewn fields combined with machine learning can offer a novel approach to assist in search and recovery efforts. Other studies have explored drone-based meteorite detection as well [1-4], yet existing approaches are often tied to specific terrains and are difficult to adapt to the diverse land-cover types that we encounter across Europe.

Here we present a flexible training-data generation strategy and detection pipeline that leverages transfer learning with a pre-trained Convolutional Neural Network (CNN) architecture to identify fusion-crusted meteorites. Museum specimens were photographed from multiple orientations on an automated rotating stage and composited onto representative ground backgrounds to synthesize a varied training set. After fine-tuning the network on this dataset, we validated it on drone imagery containing hidden meteorites in grassy environments at multiple flight levels and in a demarcated search area that was surveyed by drone. The system consistently detected meteorites across these controlled field tests, while also highlighting the importance of tuning image scale, flight altitude, and detection-window size.

As our approach to training data generation is adaptive, we can tune the pipeline to strewn field-specific land cover types, providing a practical route toward deployment in future search campaigns. With the pipeline tested in a controlled field setting, we now await the next meteorite-dropping fireball event in the Netherlands or surrounding countries to conduct real-world field trials to validate this novel airborne detection strategy. ... Read more

The Isidis Planitia impact basin on Mars is located on the north-south dichotomy boundary, bordered by Utopia Planitia and the Syrtis Major volcanic province. The basin records a long geological history of global and regional events of impact-induced, volcanic and sedimentary processes. This is evident in the presence of a high-density subsurface mass concentration, the strongest on Mars outside the major volcanic provinces. The nature of this interior structure remains poorly understood despite modelling efforts (e.g., [1-3]). Isidis Planitia’s surface also hosts the densest clustering of pitted cones [4,5]. The formation mechanism of these landforms, characterised by a conical mound with a central depression, remains debated as volcanic [6], sedimentary [4] or glacial [7].We present an integrated approach to Isidis Planitia, showing that pitted cones are topographically constrained by surface wrinkle ridges driven by its subsurface structure. The subsurface is modelled using impact scaling laws combined with geological context to formulate a multi-layered model, which is fit to the local gravity field. Resultant structural elements are consistent with impact theory [8-10], estimated structures below Lunar basins [11,12], as well as mapped basins [13]. However, the gravity field cannot be constrained using infill, scaling laws and realistic density values. The models require mantle-like materials in the innermost parts of the basin. This element does not reconcile with expectations of impact theory nor basin infill, and is interpreted as significant post-impact plutonic intrusions.This intrusive element is linked to a set of wrinkle ridge surface expressions with anomalous direction and dip. Two distinct formations of ridges are identified: an initial radial set of ridges and a latter concentric inward-dipping formation. This anomalous concentric set is not mirrored in Lunar basins [14,15] nor in Martian basins Utopia and Hellas [16,17]. The initial set is likely driven by regional compressive effects. The latter formation is driven by a stress field in the inner basin, which could be achieved during pluton inflation.The pitted cones are shown to correlate with the basin topography dominated by the wrinkle ridges. The population conforms to both sets of pre-existing wrinkle ridges in distinct surface flow patterns. They are most consistent with volcanic rootless cones formed by lavas interacting with near-surface volatiles. The lava could be sourced from the intrusive magmatism, addressing the lack of other sources [6]. Overall, this study links Isidis Planitia’s subsurface structure to surface morphology. It could redefine the complex and dynamic basin, offering new insights into the active geological evolution of Mars. ... Read more

In planetary science we study a myriad of internal and external geological processes that are shaping the planets and moons inside the solar system. Thanks to the remote exploration by satellites, we can reconstruct the geologic, climatic and possibly biologic past of these planetary bodies. Key focal points targeted by the Dutch community are planetary evolution and the past and present-day habitability. Herein too, lies an important challenge for our education approach for engineering students. The curricula of a typical Aerospace Engineering student are well-aligned to offer training in solving the engineering challenges of space flight and operations of spacecraft. While our students are not trained as geologists, these future space engineers and planetary scientists would benefit from developing and obtaining a level of proficiency of geological concepts at higher learning levels that help them understand the science drivers for instruments and their potential and limitations on space missions. We believe that the development of such concepts can be supported by an ‘analogue approach’, which involves using materials from Earth that resemble those observed on other planetary bodies [1]. It offers learners an unparalleled opportunity to augment their textbook knowledge with first-hand, real-world observations of materials that drive scientific questions and design requirements for planetary missions. However, rock collections for teaching in the field of geoscience are often compiled and expanded over decades by the involved teaching staff. This means that existing geological collections are not aligned a priori to the educational needs in planetary science teaching. Afterall, collections with a relevant scope for planetary science will be strongly dependent on outcomes of past and present planetary missions.

Here we report on the development of the Planetary Analogue Rock Collection (PARC) and the first outcomes of using PARC in teaching activities. We have recently started involving hands-on materials and to study how these can contribute to a better understanding of numerical approaches and in-situ measuring strategies by space missions. Based on our initial activities and evaluations for the courses ‘Physics of Planetary Interiors’ and ‘Measurement Strategies for Planetary Science Missions’, we found that the assimilation of theoretical knowledge on rocks and minerals benefits from relevant examples and the use of hands-on materials. During the project we aimed to refine and improve our educational formats, expanded the collection with new specimen collected in Iceland and set-up an approach and platform to create and host ‘digital twins’ (3D models) of selected rock examples. Aligned to digital collection trends in education [2-4] these 3D models allow us to develop blended-learning activities to support the students' learning process. We will present our approach to the collection, its use in courses, we propose the use of "educational analogues" to complement [1] and discuss some key outcomes that merits further consideration for those seeking to use hands-on collections in education of the generation of digital natives. ... Read more

On Earth, hillslope processes are typically driven by gravity and lubricated by liquid water. The slope angle, availability of water, and material composition ultimately determine the type of mass-movement, the flow dynamics, and the morphology of the resulting depositional landforms. Therefore, terrestrial hillslope landforms have served as our guide in the interpretation of hillslope landforms and their formation processes on other planetary bodies (e.g. the Moon, Mars). However, pioneering work has shown that gravity has a significant effect on the dynamic angle of repose (Kleinhans et al., 2011), the transition of bedload to suspended load in fluvial sediment transport (Braat et al. 2024), and the settling speed of fine sediment in water (Kuhn et al., 2015). This raises the questions if and how gravity affects the non-linear flow dynamics of hillslope mass movements and the morphology of their depositional landforms.

In this study, we experimentally explored the effects of gravity on the dynamics of dry mass movements and those lubricated by a liquid. We performed rotating drum experiments under varying gravity (from ~0.1g to 2g, with g=9.81ms-2). The lower and hyper-gravity conditions were created by flying, respectively, parabolic trajectories and steep turns with a Cessna Citation II aircraft (PH-LAB), in which the rotating drum set-up was installed. In the rotating drum (diameter=50 cm), we tested how dry and wet granular flows responded to different gravity by measuring flow depth, density, compaction and dilation, and internal grain dynamics. Reference experiments with varying drum-rotation speeds were performed under Earth gravity to determine the relative effects of centrifugal force versus gravity, and aircraft vibrations.

Preliminary analyses show that gravity changes the dynamics of both dry and wet granular flows in our drum, and that these effects are more pronounced for wet granular flows. Under higher gravities (>1g), the granular flows become more compacted, which pushes the water out of the mixture and decreases the water content of the granular flow itself. As a result, the interparticle friction increases and the centre of mass shifts upslope in the drum. At lower gravities (<0.7g), the granular flows dilate, increasing the pore space in the sediment-water mixture, resulting in an increase in air in the inter-particle pore space. This increases the relative importance of flow resisting forces relative to lubricating forces within the mixture, shifting the center of mass of the mixture upslope. The results under varying gravities seem to imply that, for a given ratio of sediment to water, an optimum gravity exist for peak water-lubricated granular flow mobility.

Comparison of the results under varying gravity with those of the reference experiments with varying drum rotation speeds under 1g confirm that gravity has a unique effect on the flow dynamics of granular flows. In particular, on the dilation of the flowing mixture and the interparticle behaviour. However, as changing drum-rotation speed also shifts the centre of mass of the flowing mixture, further analysis will focus on the combined effects of dilation, shifting centre of mass, and the steepening slope in the drum for all experiments. ... Read more

In planetary geophysics, the translation of geodetic and geophysical measurements into interior properties represents a complex inverse problem (see e.g. [1-2]). This challenge is inherently characterized by non-uniqueness, mathematically correlated parameters, and the necessity for rigorous uncertainty quantification. With upcoming flagship missions—such as ESA’s Jupiter Icy Moons Explorer (Juice) [3] and NASA’s Europa Clipper [4]—preparing to deliver high-precision datasets from the Jovian system, the planetary science community requires advanced computational frameworks to interpret these observations. Historically, MCMC Bayesian inversions for constraining planetary interiors have relied on ad-hoc workflows, hard-coded parameterizations, and target-specific libraries (see e.g. [1-2]). Such an approach can be limiting, as it restricts cross-disciplinary reproducibility and scalability and a systematic comparison of analyses between different target bodies.

To overcome these limitations, we present geoMCMC, an open-source Python library developed to provide a unified, consistent, and modular computational framework for planetary interior analysis. By standardizing the inversion workflow, this library aims to enhance model sharing, cross-disciplinary collaboration, and methodological reproducibility across the planetary science community. Originally conceptualized to investigate the subsurface oceans of icy satellites [5], geoMCMC has evolved into a generalized, high-performance computational framework designed for the Bayesian inversion of both rocky and icy planetary bodies.

At its core, the software relies on a plugin-based architecture orchestrated by a central inference problem pattern. As illustrated in Fig. 1, this architecture explicitly decouples statistical inference from physical modeling through a five-pillar design: the Body (managing planetary layer states and geometry), the Parameter Set (linking statistical priors to interior attributes), the Observation Set (handling geophysical forward models), the Constraint Set (enforcing physical assumptions), and the Sampler (the Bayesian inference engine). This modularity ensures that state definitions, geometry, model constraints, and sampling algorithms function as independent, interchangeable components. For instance, users can seamlessly swap constraint modules, i.e. the functional blocks responsible for enforcing fundamental a priori physical assumptions, such as mass balance, hydrostatic equilibrium, or advanced thermodynamic models. In fact, these modules automatically resolve interdependent properties to guarantee physical consistency before any forward model is evaluated. Furthermore, the architecture is designed for high-performance parallel processing, allowing computationally intensive physical models to be offloaded to a high-efficiency compiled C++ kernel. ... Read more

ars was long thought to be in a quiescent state with minimal geodynamic processes taking place at present. However, NASA's InSight mission shed light on the planet's present-day tectonic activity, part of which is likely related to mantle plumes and associated magmatic that, in the recent past, might have contributed to building up the Martian atmosphere through mantle outgassing. We propose a dedicated gravimetric satellite mission for Mars: the Mars Quantum gravity sensing of Interior Structure and atmosphere mission (MaQuIS) to understand these intricate dynamic processes and use gravity observations to constrain the interior structure and geologic evolution of the red planet. The mission will enable us to decipher Mars' ongoing geodynamic activity, the structure of its lithosphere, as well as to probe for subsurface water reservoirs and to characterise the temporal dynamics of the atmosphere. MaQuIS follows a well-crafted mission scenario, inherited from the successful Gravity Recovery and Climate Experiment (GRACE) and Gravity Recovery and Interior Laboratory (GRAIL) missions deployed around Earth and the Moon, respectively. Compared to its predecessors, MaQuIS will include state-of-the-art quantum sensing technologies to improve the detection of fine variations in Mars' gravitational field and maximize the mission's scientific return. MaQuIS will contribute to the following main science objectives:

1. Uncover the evolution of Mars by studying interior dynamics, detailed structure and composition of the planet's lithosphere and deep mantle.

2. Capture Mars' climate history by monitoring the density of the planet's upper atmosphere and uncover the monthly, seasonal, and long-term changes.

3. Explore potential scenarios for the fate and sequestration pathways of Mars' surface liquid water.

These primary mission goals will have profound and long-lasting impacts on the study of Mars, shedding new light on Mars' geologic evolution and ongoing interior and atmosphere activity.

Activities are ongoing to increase the TRL-level of the instrument technology. Both improved systems for the main instruments are being developed. LRI link acquisition is being developed to improve the initialisation phases. Also, other laser frequencies are being looked at to be able to share laser sources for the LRI and CAI accelerometers. Improvements of the internal layout of the CAI instrumentation help in detecting bottlenecks in the new technology. Mission design studies are improving the understanding of the impact of certain orbit choices to the precission and coverage of the observations. Finally we will also present some preliminary CFD studies performed on the whole mission design, highlighting that the mission is technological feasible and will provide excellent data to improve our understanding of Mars. ... Read more

Mitigation of the threat from airbursting asteroids requires an understanding of the potential risk they pose for the ground. How asteroids release their kinetic energy in the atmosphere is not well understood due to the rarity of large impacts. Here we present a comprehensive, space-to-laboratory characterization of an impact of an L chondrite, which represents a common type of Earth-impacting asteroid. Small asteroid 2023 CX1 was detected in space and predicted to impact over Normandy, France, on 13 February 2023. Observations from several independent sensors and reduction techniques revealed an unusual but potentially high-risk fragmentation behaviour. The nearly spherical 650 ± 160 kg (72 ± 6 cm diameter) asteroid catastrophically fragmented at a dynamic pressure of 4 MPa around 28 km altitude, releasing 98% of its total energy in a concentrated region of the atmosphere. The resulting shock wave was spherical, not cylindrical, and released more energy closer to the ground. This type of fragmentation increases the risk of substantial damage at ground level. These results warrant consideration for a planetary defence strategy for cases where a >3–4 MPa dynamic pressure is expected, including planning for evacuation of areas beneath anticipated disruption locations. ... Read more

Planetary habitability is shaped by a combination of interior, surface, and external processes that interact to determine the long-term evolution of a planet. Understanding planetary habitability within our solar system requires comparing these processes across planets and moons with those on Earth, the only currently known habitable planet. Much of our knowledge about solar system bodies has been obtained through planetary exploration, which remains essential for advancing our understanding.

To strengthen this effort, a new Planetary Science Network in the Netherlands is being established. The network builds on the existing expertise in solar system research within the Dutch scientific community and aims to develop a framework for identifying key observables that enable the detection and assessment of planetary habitability through both in situ and remote sensing observations.

The research is organised around three main themes. The first theme focuses on planetary interiors, using Ganymede as a case study. The second theme examines surface morphology, particularly landform development, with Mars serving as the primary case study. The third theme investigates surface composition by comparing Earth's oldest geological surfaces with those of Mars and icy moons.

Through a synergistic approach within the network, these themes will produce both case-study-specific observables and more general observables that can be applied across the solar system and to the growing number of known exoplanetary systems. The network aims to strengthen the position of the Dutch planetary science community and support active contributions to the development of instruments for future planetary exploration missions. In addition, it will foster closer collaboration with the strong Dutch exoplanet research community, helping to bridge the gap between what should ideally be observed and what is currently feasible to observe.

This presentation introduces the network, its research goals, and its strategy for advancing the study of planetary habitability, while inviting collaboration and discussion within the international planetary science community. ... Read more

In planetary science we study a myriad of internal and external geological processes that are shaping the planets and moons inside the solar system. Thanks to the remote exploration by satellites we can reconstruct the geologic, climatic and possibly biologic past of these planetary bodies. Key focal points targeted by the Dutch community are planetary evolution and past and present-day habitability. Herein too, lies an important challenge for our education approach for engineering students. Their curricula are well-aligned to offer training in solving the engineering challenges of space flight and operations of spacecraft. While our students are not trained as geologists, these future space engineers and planetary scientists would benefit from developing sound geological concepts at higher learning levels that help them understand the science drivers for instruments and their potential and limitations on space missions. We believe that the development of such concepts can be supported by an ‘analogue approach’, which involves using materials from Earth that resemble those observed on other planetary bodies [1]. It offers learners an unparalleled opportunity to augment their textbook knowledge with first-hand, real-world observations of materials that drive scientific questions and design requirements for planetary missions. ... Read more

Meteorites offer valuable insights into the composition of asteroids and geological processes contributing to planet formation inside the solar system. Their rapid retrieval after fireball sightings allows this science potential to be used. Finding new meteorites is notoriously difficult due to various complicating factors. A promising search strategy can involve the aerial vantage point of drones (aka: UAV, RPAS). However, drone regulations by the European Union Aviation Safety Agency (EASA) and complex zonation of airspace will impact flight operations, which makes drone-assisted searching in Europe more complex than in e.g. desert environments. Here we present the results of an interdisciplinary desk study, which aimed at proposing a conceptual framework for drone-assisted meteorite searching. We propose the development of an open-source detection and coordination tool to improve aerial assistance by drones during field searches. The design provides drone enthusiasts (referred to as ‘community drones’) and researchers with a platform to coordinate joint drone-based search operations. Image processing is envisioned to take place via a convolutional neural network pipeline, after which high-likelihood locations are identified and manually verified to recover a potential meteorite. This approach will require the development of multiple models to account for variations in soils and vegetation. The tool supports multi-drone coordination, providing path planning functionality and support for a broad range of (commercially) available drone models (e.g. DJI) and sensor types (e.g. RGB, thermal). Considering EASA drone regulations, the use of the DJI Mini 3 Pro is favoured as an accessible community drone. Follow-up research, implementing the proposed conceptual approach, should validate the design presented here and highlight practical areas of improvement. ... Read more

Assessing and classifying rocks on the basis of their visual traits has been a long standing practise for geoscience fields. For planetary geoscience the interaction with astrogeological materials such as meteorites and impactites contributes to the comprehension of their properties, alteration and, ultimately, solar system formation processes. In the wake of the SARS-CoV-2 (COVID-19) pandemic we explored alternative options to involve meteorites and impactites in remote teaching. Simultaneously, this opened up the integration of meteorites in teaching activities for large groups of learners. We have developed a workflow using Structure from Motion (SfM) photogrammetry to render high-resolution digital 3D models of meteorites and impact rocks. This procedure was used to create a virtual collection with tens of examples that were made publicly accessible in an online environment. The digital 3D models can be inspected by rotating and zooming, while annotations in clickable pop-ups direct users to key features or provide background information and data. We evaluated the user experience and discuss how virtual collections can be created and used for blended learning. Meanwhile, we have explored the use of models in the ‘Delft Meteorite Lab’ in academic teaching, public outreach and science applications. The virtual collection also offers a potential resource to aid the identification of putative meteorite finds by the general public. Looking towards the future, a new ‘Dutch Meteorite Lab’ aims become a national hub for education and research to explore meteorites and meteorite taxonomy based on specimen available in various study collections across the Netherlands. ... Read more

Meteorites are valuable resources in planetary geoscience, since they provide invaluable insights into the composition and origin of planetary bodies, enhancing our understanding of planet formation and the solar system. Despite occurrences of meteorite-dropping fireballs observed every 2 years, traditional field search campaigns in the Netherlands have faced challenges in retrieving fragments. In this presentation we will outline an innovative approach for meteorite recovery through the integration of drones and machine learning algorithms. To enhance search efforts, drones can be used to gain access to restricted fields and increase efficiency. The proposed strategy employs Convolutional Neural Networks (CNNs), a type of machine learning algorithm, to analyze drone imagery and identify potential meteorites. In order to train the artificial neural network, we created an extensive library of image data of fusion-crusted meteorites from the Naturalis meteorite collection placed on a backdrop of various field and soil conditions. The algorithm was tested during a field experiment at Unmanned Valley, Valkenburg, South Holland, using real meteorites and ‘meteorwrongs’ (objects resembling meteorites). During the drone survey we captured images of the target area and then implemented our detection strategy based on machine learning to the new image data set. In this presentation we will discuss the results and future steps. ... Read more

The computation of the dark flight of a bright fireball requires knowledge of the atmospheric parameters. In particular wind and wind direction as a function of height are crucial for an accurate trajectory. In this paper we compare different sources of sounding balloon and model data, and study the effect on the dark flight. ... Read more

Stereoscopic viewing of overlapping aerial image pairs under a mirror-stereoscope has been a common approach to visually study the 3D architecture of landscapes and their constituting landforms. While superseded by digital means for various science applications, the depth perception offered by stereoscopes still has potential to introduce novice learners to the spatial dimensions and relations of landforms, in particular those lacking prior geoscience training. In this presentation I will discuss an application of stereoscopes in planetary science education. Similar to aerial surveying and earth observation, planetary science too relies on expert-driven and semi-automated image interpretation to infer landform and landscape genesis to increase our understanding of planetary evolution. The use of HiRISE stereo image pairs of the Mars Reconnaissance Orbiter allows similar 3D viewing as with conventional aerial photos. We will discuss an activity format involving stereo pairs of the Jezero crater delta, the landing site of the M2020 Perseverance rover and Ingenuity drone, and then review some early results and ideas for future iterations. ... Read more

The long-axis orientation of elongated sand grains in aeolian systems is dependent on saltation of grains and orientation to the dominant wind direction. This relationship can be used to understand the dynamic environment on Mars based on close-up images of the surface taken by microscope cameras. We perform(ed) experiments at the Aarhus Mars Simulation Wind Tunnel, a closed circuit, low-pressure wind tunnels that allows saltation to be studied at different pressures and friction velocities. Close-up images taken of the sandbed were used with image segmentation methods to delineate grains and determine the preferred orientation of particles. Similar methods have been used on thin sections taken from well-studied and oriented sediments on Earth. Our study aims to generate and study oriented sediments under Martian analogue conditions to investigate how grain orientation (imbrication) is modulated in low pressure environments. We will discuss the effects of different air pressures and friction velocities on the observed preferred orientation of particles in the sandbed and evaluate the implications for aeolian processes in different atmospheric conditions. While tailored to active aeolian sediments, this method could offer insights for interpreting lithified samples such as sand stone outcrops studied by Mars rover to investigate aeolian processes in the past. ... Read more

Introduction: The Netherlands host several meteorite collections including collections at Utrecht University, Delft University of Technology, and Naturalis Biodiversity Centre. Historically, these collections have been carefully stored without much exposure, even though meteorites are the ideal materials to study first-order properties of solar system materials. Exploring meteorites can offer an important formative learning experience, not only for students of all ages and experienced researchers, but also for the general public. The main challenges with studying meteorites are their preservation and handling, and the resulting small group sizes in which meteorites can be studied. Further motivated by the shift towards online teaching driven by the SARS-CoV-2 (COVID-19) pandemic, we started exploring ways to make the meteorite collection accessible to students and the public at large. First, the Delft Meteorite Lab (DML, http://delftmeteoritelab.nl) was established, shortly followed by the Utrecht Meteorite Lab (UML, https://utrechtmeteoritelab.sites.uu.nl/).
Approach: The development of both online labs is largely driven by student participation. First, 2D images are taken of the meteorites, and displayed on the UML website, accompanied by a brief description, including name, location of fall or find, year of collection, and classification. Then, 3D representations of the meteorites are made via Structure from Motion (SfM) photogrammetry using the software Agisoft Metashape Professional and stored on SketchFab, with links to the DML and UML websites. Of selected specimens thin sections are made and full thin section microscope photographs and sections in PPL and XPL will be added to the online collection (AXIOM).
Use in education: DML and UML are already actively used in education. The descriptions of the meteorites for the UML are written by the students as part of the Planetology, an Introduction course taught at the department of Earth Sciences at Utrecht University. 3D models from the DML are used to familiarise students with properties of meteorites that can be related to specific processes, such as fusion crusts from ablation during atmospheric entry, compositional differences between differentiated and undifferentiated meteorites [1,2]. Also, the DML 3D models are used for a meteorite or meteorwrong practicum during the courses Planetary Science at BSc and MSc level.
Outreach: Over the past years, the 3D models have been used in several outreach activities. In an online lecture for the popular ‘Universiteit van Nederland’, we discussed several Dutch meteorites using 3D models in a chroma key (‘green screen’) environment to explain properties of meteorites, their taxonomy and implications for planet formation. Based on the renderings, 3D prints have been made of the Dutch Utrecht (’Loevenhoutje’ fragment) and Broek in Waterland meteorites for outreach activities at the Space Expo Museum. To mark the 150-year anniversary of the Diepenveen meteorite fall on 27 October 2023, 6:1 scaled model was created for a monument based on the 3D model of Diepenveen and revealed on the day of the impact anniversary in the town’s centre.
Outlook: Building upon our current experiences with the Delft Meteorite Lab focussing on photogrammetry workflow development and educational applications, and the Utrecht Meteorite Lab, linking to data from various material characterisation methods, we aim to create the ‘Dutch Meteorite Lab’as a national hub to explore meteorites in study collections found across the Netherlands.
References: [1] de Vet S. J. (2024) Proceedings of the IMC, Redu, 59-62 [2] Guedes D., Zucolotto M., Silva L., Brenha S., and Canelle J. B. (2010). Meteoritics and Planetary Science Supplement, MetSoc 73. ... Read more

Regmaglypts are shallow depressions on meteorite surfaces formed by ablation processes during atmospheric entry. These features can potentially offer insights in breakup events. However, quantitative methods to analyse regmaglypts have not yet been proposed to date. Here we present the results of a study to evaluate breakup processes during the luminous flight by analysing regmaglypt morphometrics. We developed a novel approach based on a 3D shape model of the Broek in Waterland meteorite that was generated using photogrammetry. We converted sections of the 3D model into a smoothed Digital Elevation Model (DEM) that contained the fracture surfaces adorned with regmaglypts. Lending techniques from terrain analyses, we extracted Land Surface Parameters (LSP) and delineated regmaglypts based on the mean curvature inflection point. The outliers of the regmaglypt population were discarded based on mean and total curvature scatter plots. The mean, profile, tangential, total and Gaussian curvatures were found to be most descriptive of regmaglypt morphologies. Various other curvature types were tested and found to be consistent across the studied regmaglypt population. Using this initial framework, we found that the two regmaglypted surfaces of the Broek in Waterland meteorite appear to be similar. This would reflect similar formative conditions, which we interpret to be most consistent with formation from the same breakup event. Future studies will aim to expand the presented method to regmaglypt populations of other L6 meteorites to understand how surface characteristics can inform us on ablation and breakup processes. ... Read more

FRIPON project

The FRIPON fireball project was initially conceived and founded in France in 2014 with a grant from the ANR (Agence Nationale de la Recherche), the objective was to cover the country with a dense network of all-sky cameras (~ a hundred with 80 km spacing). We built (Colas at al 2020) [1] a centralized network, a data storage architecture and a real-time data processing (astrometry of each camera, triangulation of each event to calculate the trajectory of the bright flight and finally determination of the scientific parameters: orbit, incoming mass, final mass, etc.). A catalog of orbits is produced each year and is available on the fireball.fripon.org website. The FRIPON project is designed as a real-time network, the aim of which is to trigger a search in the field within 24 hours of the fall in order to recover fresh meteorites.



Extension and results

The architecture developed for the network allows for easy expansion, and from 2016, scientists from neighboring countries were interested in joining the project using the same hardware, software and infrastructure. The main extensions involved Italy (PRISMA), Germany (FRIPON-Germany), Romania (MOROI), the United Kingdom (SCAMP), Canada (DOME), the Netherlands (DOERAK), Spain (SPMN), Belgium (FRIPON-Belgium), Switzerland (FRIPON-Switzerland), South America (FRIPON-Andino), Morocco (MOFID) and Senegal (ASAMAAN). FRIPON (www.fripon.org) is now an international project and the French network is now FRIPON-VigieCiel (www.vigie-ciel.org) a merger of the camera network and of the Vigie-Ciel citizen science project supported by Muséum national d'Histoire naturelle with the aim of involving the general public in finding meteorites by learning how to identify them and thus take part in research. Ten years after the start of the network, we now have 250 active cameras, we have obtained more than 10,000 orbits and our data has been used in the recovery of 7 meteorites (Cavezzo 2020, Winchcombe 2020, Kindberg 2021, Saint-Pierre-le-Viger 2023, Matera 2023, Menetréol 2023, Ribbeck 2024). It is important to note that over these 10 years, more than 20 searches have been organized without positive results, as the recovery efficiency is often far from 100% due to vegetation, private land, etc.

Recovery statistics

Roughly 600 detections per year included at least one French camera, as described in (Colas et al 2020) [1] this corresponds to objects larger than 1 cm and is compatible with the surface area of the national territory (10⁶ km²) according to the previous estimate (Brown et al 2002) [2]. As it also predicts the fall of around 10 meteorites per year for France, we hoped at the start of the project to recover about one meteorite per year, which seems realistic: 50% of meteorites fall during the day, cloud cover is around 50% and ground searches are difficult one time out of two. Another clue is that in the 19th century, one meteorite was recovered every two years in France (Colas, 2020) [1]. Unfortunately, after 10 years of operation, we have only recovered 2 meteorites in France, which is a little disappointing but still better than the 20th century efficiency of one meteorite every 10 years. In the end, the realistic recovery rate seems close to one meteorite per year, but for all of Europe! Since the start of the program in 2015, we found 40 events with a final mass greater than 100g and 10 for 500g and more. These data are compatible with our initial estimate, but the recovery success is low due partly to agricultural changes from small farms where owners could easily identify "strange" stones to big intensive farms.

The case of 2023 CX1

Asteroid 2023 CX1 was discovered by Krisztián Sárneczky of the Konkoly Observatory on 12 February 2023, just 7 hours before it was due to hit the Earth, which made it possible to track it and calculate its orbit very precisely. Most of the telescopic data was obtained by amateurs. It is important to point out that we had to use data from different networks (FRIPON, GMN, AllSky 7, UKMON) and security cameras to calculate the atmospheric entry parameters. The potential strewnfield was then determined in parallel by several groups. The FRIPON/Vigie-ciel collaboration quickly mobilized its network and set up a field search. 4 stones were thus found by children, 4 others by amateurs and finally only 4 others by scientists who were not even meteorite specialists! In the end, amateurs played a fundamental role in the recovery success at all stages of the event: telescopic and fireball data as well as field searches.

Conclusion

The 7 meteorites found in Europe in the last 5 years would not have been found without the presence of fireball networks to give the alert and calculate the strewnfields. In Europe, we are fortunate to have a number of networks (FRIPON, GMN, AllSky7, DFN, etc.) that enable us to detect these events exhaustively. The success of our research is also largely due to citizen science programs such as Vigie-Ciel, which make it possible to organize effective field searches.



References: [1] Colas et al. (2020) Astronomy and Astrophysics 644, A53; [2] Brown et al (2002) Nature, Volume 420, Issue 6913 ... Read more

The visible rate of meteors is dependent on various local viewing condition during shower peak nights. The interrelationship of the visible fraction of the night sky, radiant elevation and effects of the light pollution on sky brightness confounds outreach efforts to manage realistic expectations for visual meteor observations by the public. The Urban Meteor Map offers a map-based forecast of hourly rates to help make the effects of local viewing conditions more insightful. The project generates maps based on raster data for parameters in the Zenithal Hourly Rate formula. A Digital Surface Model (DSM) covering the Netherlands was used to generate maps of the visible percentage of the sky. At 5 m resolution this DSM offers insights into obstruction by buildings, vegetation and topography. To incorporate effects of light pollution, a national sky brightness map for cloudless nights was converted into Naked Eye Limiting Magnitudes (NELM). Combined with known shower parameters such as population index and radiant height, maps were generated with hourly rates forecasts at local and national scales. Ultimately, observing conditions will remain dependent on the individual observers, their night adaptation and local light interference. The Urban Meteor Map aims to helps raise awareness for the effects of light pollution, and thus promotes exploration of local living environment to seek the best viewing spots for meteor showers. ... Read more

Meteorites are valuable resources in planetary geoscience, since they provide invaluable insights into the composition and origin of planetary bodies, enhancing our understanding of planet formation and the solar system. Despite occurrences of meteorite-dropping fireballs observed every 2 years, traditional field search campaigns in the Netherlands have faced challenges in retrieving fragments. In this presentation we will outline an innovative approach for meteorite recovery through the integration of drones and machine learning algorithms. To enhance search efforts, drones can be used to gain access to restricted fields and increase efficiency. The proposed strategy employs Convolutional Neural Networks (CNNs), a type of machine learning algorithm, to analyze drone imagery and identify potential meteorites. In order to train the artificial neural network, we created an extensive library of image data of fusion-crusted meteorites from the Naturalis meteorite collection placed on a backdrop of various field and soil conditions. The algorithm was tested during a field experiment at Unmanned Valley, Valkenburg, South Holland, using real meteorites and ‘meteorwrongs’ (objects resembling meteorites). During the drone survey we captured images of the target area and then implemented our detection strategy based on machine learning to the new image data set. In this presentation we will discuss the results and future steps. ... Read more