David Cantillo | Searcharxiv

arXiv2026

Physical Characterization of Moon Impactor 2025-010D

Renewed interest in lunar exploration is creating a growing population of poorly tracked cislunar objects, some of which will ultimately impact the Moon$^{1}$. The ultimate fate of rocket upper stages or failed mission payloads is often unknown and unplanned. Determining the origin and physical properties of such objects will become increasingly important as sustained lunar exploration places humans and infrastructure on the surface$^{2;3;4;5}$. Here we present a ground-based physical and dynamical characterization of 2025-010D, a Falcon 9 upper stage predicted to impact the lunar farside on 2026 August 05. Backward propagation of its orbit independently links the object to the ``Ghost Riders in the Sky'' launch, while visible and near-infrared spectroscopy distinguishes it from natural objects and reveals absorption bands consistent with spacecraft thermal control materials. Photometric lightcurves confirm its elongated shape and reveal an unexpected change of more than 8 s in its $\sim$7 min rotation period during observations. We predict an impact between Bell and Einstein craters at $\sim$2.4 km s$^{-1}$, producing a crater $\sim$40 m in diameter. Since its provenance is independently known, 2025-010D provides a benchmark for identifying and characterizing future cislunar objects of uncertain origin.

astro-ph.EP↗

arXiv2023

Mineralogical Characterization and Phase Angle Study of Two Binary Near-Earth Asteroids, Potential Targets for NASA's Janus Mission

Ground-based characterization of spacecraft targets prior to mission operations is critical to properly plan and execute measurements. Understanding surface properties, like mineralogical composition and phase curves (expected brightness at different viewing geometries) informs data acquisition during the flybys. Binary near-Earth asteroids (NEA) (35107) 1991 VH and (175706) 1996 FG3 were selected as potential targets of the National Aeronautics and Space Administration's (NASA) dual spacecraft Janus mission. We observed 1991 VH using the 3-m NASA Infrared Telescope Facility (IRTF) on Mauna Kea, Hawaii, on July 26, 2008. 1996 FG3 was observed with the IRTF for seven nights during the spring of 2022. Compositional analysis of 1991 VH revealed that this NEA is classified as an Sq-type in the Bus-DeMeo taxonomy classification, with a composition consistent with LL ordinary chondrites. Using thermal modeling, we computed the thermally corrected spectra for 1996 FG3 and the corresponding best fit albedo of about 2-3% for the best spectra averaged for each night. Our spectral analysis indicates that this NEA is a Ch-type. The best possible meteorite analogs for 1996 FG3, based on curve matching, are two carbonaceous chondrites, Y-86789 and Murchison. No rotational variation was detected in the spectra of 1996 FG3, which means there may not be any heterogeneities on the surface of the primary. However, a clear phase reddening effect was observed in our data, confirming findings from previous ground-based studies.

astro-ph.EP↗