¹Kareta, Theodore,²Fuentes-Muñoz, Oscar,¹Moskovitz, Nicholas²Farnocchia, Davide,³Sharkey, Benjamin N. L.
Astrophysical Journal Letters 979, L8 Open Access Link to Article [DOI 10.3847/2041-8213/ad9ea8]
¹Lowell Observatory, Flagstaff, AZ, United States
²Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, 91109, CA, United States
³Department of Astronomy, University of Maryland, 4296 Stadium Dr., PSC (Bldg. 415) Rm. 1113, College Park, 20742-2421, MD, United States

The near-Earth asteroid (NEA) 2024 PT5 is on an Earth-like orbit that remained in Earth’s immediate vicinity for several months at the end of 2024. PT5’s orbit is challenging to populate with asteroids originating from the main belt and is more commonly associated with rocket bodies mistakenly identified as natural objects or with debris ejected from impacts on the Moon. We obtained visible and near-infrared reflectance spectra of PT5 with the Lowell Discovery Telescope and NASA Infrared Telescope Facility on 2024 August 16. The combined reflectance spectrum matches lunar samples but does not match any known asteroid types—it is pyroxene-rich, while asteroids of comparable spectral redness are olivine-rich. Moreover, the amount of solar radiation pressure observed on the PT5 trajectory is orders of magnitude lower than what would be expected for an artificial object. We therefore conclude that 2024 PT5 is ejecta from an impact on the Moon, thus making PT5 the second NEA suggested to be sourced from the surface of the Moon. While one object might be an outlier, two suggest that there is an underlying population to be characterized. Long-term predictions of the position of 2024 PT5 are challenging due to the slow Earth encounters characteristic of objects in these orbits. A population of near-Earth objects that are sourced by the Moon would be important to characterize for understanding how impacts work on our nearest neighbor and for identifying the source regions of asteroids and meteorites from this understudied population of objects on very Earth-like orbits.

^1,2Dorian Leger,¹Fardin Ghaffari-Tabrizi,³ Matthew Shaw,⁴Joshua Rasera,⁵David Dickson,^6,7Baptiste Valentin,⁸Anton Morlock,¹Freja Thoresen,¹Aidan Cowley Proceedings of the National Academy od Science of the USA (PNAS) 122, e2306146122 Link to Article [https://doi.org/10.1073/pnas.2306146122] ¹Spaceship, European Astronaut Center, Exploration Preparation, Research and Technology Team (ExPeRT), Directorate of Human and Robotic Exploration, European Space Agency, Cologne 51147, Germany ²Cx Bio, Luxembourg 2521, Luxembourg ³Future Mining Team, Commonwealth Scientific and Industrial Research Organisation, Mineral Resources, Clayton VIC 3168, Australia ⁴Department of Earth Science and Engineering, Imperial College London, London SW7 2AZ, United Kingdom ⁵Center for Space Resources, Colorado School of Mines, Golden, CO 80401, Colorado ⁶Spaceship FR, Centre National d’Etudes Spatial, Toulouse 31400, France ⁷Belgian Air and Space Component, Control & Reporting Centre, Belgian Armed Forces, Brussels 1140, Belgium ⁸Karlsruhe Institute of Technology, Karlsruhe 76131, Germany Spacecraft using combustion engines require substantial amounts of oxygen for their propellant. The Moon could be a source of oxygen for rocket propellant, since the material composing the lunar surface can be processed to extract oxygen. However, little is known about overall energy requirements of the processes described in the literature for oxygen extraction from lunar regolith. This knowledge gap constrains the planning of lunar missions, since the scale of energy infrastructure required for oxygen production facilities is not well characterized. This study presents an energy consumption model for oxygen production via hydrogen reduction of the mineral ilmenite (FeTiO₃). We consider an end-to-end production chain starting from dry regolith as the feedstock. The production includes the following process steps: excavation, transportation, beneficiation, hydrogen reduction, water electrolysis, liquefaction, and zero boil-off storage. The model predicts the energy demand per kilogram oxygen produced based on adjustable parameters for each process step. As expected, the model indicates a strong dependence on feedstock composition. For regolith composed of 10 wt% ilmenite, the model predicts that a total of 24.3 (± 5.8) kWh is needed per kg of liquid oxygen produced. This study confirms that the hydrogen reduction and electrolysis steps have the highest energy requirements in the production chain. Sensitivity analysis reveals that the enrichment factor of the beneficiation process is the most critical parameter for optimizing energy utilization. Overall, this study provides a parameterized end-to-end model of energy consumption that can serve as a foundation for various production systems on the Moon.