Hybrid, Ephemeris-Quality, Measurement-Free Estimation of the Potential 2024 YR4 Lunar Impact

Hybrid, Ephemeris-Quality, Measurement-Free Estimation of the Potential 2024 YR4 Lunar Impact | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Hybrid, Ephemeris-Quality, Measurement-Free Estimation of the Potential 2024 YR 4 Lunar Impact Benjamin Hanson, Louis Carton, Thomas Bewley, Todd Ely, Aaron Rosengren This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8196369/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract For perturbed two-body motion—such as small bodies in heliocentric orbits—the Cartesian state uncertainty alternates between near-Gaussian and strongly non-Gaussian regimes over the orbit. This behavior motivates hybrid estimators that adapt to the changing character of the uncertainty. Implementation of a hybrid filter hinges on the mechanisms that control the transitions between the two frameworks. In this paper, we introduce an unscented Kalman filter/particle filter (UKF/PF) hybrid estimation strategy that uses the normalized Euclidean distance to switch from the UKF (moment-based) to the PF (ensemble-based), and the Henze-Zirkler statistic to switch back, with dynamics sourced from ASSIST, an ephemeris-quality integrator. This autonomous switching technique requires only the abstractions propagated by the respective filters, enabling complete independence from measurement updates. We demonstrate the capability of the filter by propagating the state uncertainty of the asteroid 2024 YR4 from its last reported orbit solution in November 2025 to its close approach of the Moon in December 2032. The hybrid UKF/PF accurately and efficiently predicts the lunar impact probability, velocity, angle, and potential cratering of 2024 YR4, providing all the information necessary to assess the potential fallout of the ejecta created from such an impact event. The proposed hybrid approach effectively balances and integrates the complementary strengths of both filtering frameworks in a measurement-free environment. Asteroid 2024 YR4 ASSIST Henze-Zirkler statistic Moment- vs. ensemble-based filter Normalized Euclidean distance Full Text Additional Declarations No competing interests reported. Supplementary Files UKFPFYR4animation.mp4 Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8196369","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":562518837,"identity":"87533ad3-855e-464b-8163-9c163de8a4e4","order_by":0,"name":"Benjamin 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