Updates on the Artemis III Geology Investigation

UPDATES ON THE ARTEMIS III GEOLOGY INVESTIGATION. B. W. Denevi1, L. A. Edgar2, C. I. Fassett1, J. Gross3, T. Hayden4, J. L. Heldmann5, J. Hostrawser4, D. M. Hurley1, J. M. Hurtado, Jr.6, K. Izquierdo1, B. L. Jolliff7, K. H. Joy8, Y. Liu9, A. Madera3,10, C. Moye7, G. R. Osinski4, L. M. Saper9, A. Sonke11, E. Speyerer12, A. Srivastava4, T. Sweeney6, C. N. Achilles13, B. A. Cohen13, C. Evans3, R. Ewing3, T. Graff3,14, S. J. Lawrence3, M. Miller3,14, A. W. Needham13, N. E. Petro13, R. Weber15, K. E. Young13, and the Artemis III Science Team. 1Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA, 2USGS Astrogeology Science Center, Flagstaff, AZ, USA, 3NASA Johnson Space Center, Houston, TX, USA, 4University of Western Ontario, London, ON, Canada, 5NASA Ames Research Center, Mountain View, CA, USA, 6The University of Texas at El Paso, El Paso, TX, USA, 7Washington University in St. Louis, St. Louis, MO, USA, 8The University of Manchester, Manchester, UK, 9Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA, 10Rutgers University, Piscataway, NJ, USA, 11Arizona State University, Tempe, AZ, USA, 12Intuitive Machines, Houston, TX, USA, 13NASA Goddard Space Flight Center, Greenbelt, MD, USA, 14Amentum, Houston, TX, USA. 15NASA Marshall Space Flight Center, Huntsville, AL, USA. Introduction: The Artemis III mission will provide an invaluable scientific opportunity for in-depth exploration of a landing site near the Moon’s south pole. Two crew members will spend nearly a week on the lunar surface, and their extravehicular activity (EVA) time will include geologic field work to perform in situ investigations and collect samples. Here we provide an update on science planning for the geology investigation. Geology Investigation: Because multiple potential landing sites within the Artemis III candidate landing regions will remain in consideration for some time, we developed a site-agnostic science traceability matrix (STM). The science goals and objectives in this STM align with recommendations from the Planetary Science and Astrobiology Decadal Survey [1] and NASA’s Moon-to-Mars Objectives [2] (Table 1). We identified the number and types of locations, samples, and crew observations needed to satisfy those objectives. This STM thus provides a flexible starting point for planning the geology investigation at any specific site in the south polar region, and provides the details needed to determine imaging requirements [3], estimate required sample mass and the number and types of sample containers, EVA time needed, and to assess the scientific potential of landing sites. Investigation Plan Summary: For Goal A, crystalline samples large enough to perform multiple coordinated techniques [e.g., 4,5] are key to resolving current lunar origin and magma ocean controversies. Rarer lower crustal or upper mantle components are most likely to be found as regolith fragments or within impactites. Thus, rock samples (boulder chip samples and hand-sample sized rocks) and regolith rake samples (which concentrate fragments >1 cm) are prioritized; bulk regolith samples will provide context for the measurements made on larger samples. These same types of samples (rock and raked regolith) are prioritized for Goal B, though impact melt rocks and melt-bearing breccias are the targets. The nature of ballistic sedimentation and the heavily gardened highland regolith provide a degree of chance to finding key lithic or impact melt samples for Goals A and B. We thus plan for sampling the diversity of the exploration zone by targeting areas of low slope that likely have ancient regolith, areas on slopes where material is more recently exposed, and the ejecta of larger impact craters that have exposed material from beneath the most heavily gardened regolith (which could yield samples most relevant to Goal A or B, depending on the local substrate). For Goal A, we require pristine crystalline materials, likely to be rare; for Goal B, we need robust sample statistics due to the complex impact chronology we will encounter. Both of these factors drive a desire for a large mass of returned rock samples. Distinct environments near the south pole will be targets for studying regolith evolution processes (Goal C), including regions in permanent shadow, regions with limited (<20%) illumination, ejecta near fresh craters, the disturbed area near the lander, and undisturbed well-mixed terrain. Samples of bulk regolith will yield grain size and other physical properties, as well as insight into space weathering. Rates of polar space weathering can be constrained by sampling ejecta of fresh and degraded impact craters, particularly if accompanied by samples that date crater formation (e.g., via cosmic ray exposure age determination). Rates of regolith production due to rock breakdown can be assessed from fine-grained regolith atop boulders and by sampling material derived from boulder debris aprons. Additional geotechnical information will come from stereo imaging of disturbed and undisturbed regolith, trenching, and crew observations, such as the difficulty of drive tube insertion. Goal D relies on vacuum-sealed samples to assess volatiles [see 6]. Samples collected from the coldest accessible environment and an illuminated “control” region are planned to include three separately sealed components to evaluate first-order stratigraphy of volatiles with depth: 1) surficial (upper ~cm) regolith, 2) upper portion of double drive tube (~35 cm), and 3) lower portion of double drive tube (~35–70 cm). The final landing site will be a determining factor for whether regions where nearsurface volatiles are predicted to be stable can be sampled. Sealed shallow surficial regolith samples Table 1. Geology Goals and Objectives for Artemis III. Objective priority is given in parentheses. Science Goal Science Objective (Priority) A. Understand the Origin and Early Evolution of the Moon as a Model for Rocky Planet Evolution A1. Evaluate lunar magma ocean (LMO) models for the timing and processes that led to the formation of the crust (3) A2. Constrain the composition and diversity of the lunar mantle and lower crust to test LMO models and post-LMO magmatic processes (6) A3. Establish the abundance and isotopic record of endogenic volatiles in the lunar interior to test the giant impact hypothesis for the origin of the Earth–Moon system (5) B. Determine the Lunar Record of Inner Solar System Impact History B1. Anchor the early Earth–Moon impact flux by determining the age of the South Pole–Aitken (SPA) Basin (1) B2. Test the Cataclysm Hypothesis by determining the postSPA impact chronology (2) B3. Determine how impacts redistribute materials, the impact stratigraphy at the landing site, and the provenance of samples (7) C. Determine how the Environment Controls Regolith Processes on Airless Bodies C1. Ascertain polar regolith's physical, chemical, and geotechnical properties, and the variation in regolith evolution as a function of environment (9) C2. Explore the mechanisms for space weathering in polar regions as a function of local environment (10) C3. Characterize meteoritic material, including terrestrial debris, found in the lunar regolith as a record of past lunar impactors (11) D. Reveal the Age, Origin, and Evolution of Solar System Volatiles D1. Characterize the nature, origin, age and abundance of persistent volatiles in cold environments (4) D2. Characterize the nature, origin, age, abundance, and transport processes for transient volatiles (8) D3. Determine how exploration activities modify the record of volatiles at the lunar surface (12) can provide a means to assess transient volatiles (comparisons between pre-dawn and post-dawn locations that have temperatures incompatible with longterm sequestration of volatiles) and the distribution of volatiles deposited by the lander (varying distances from the lander in regions that remained in shadow since landing). When applying the STM to representative landing sites, the investigation plan includes ~10 science stations with ~35–40 unique samples, and ~6 hours of task time at science stations (exclusive of traverse time). However, the actual utilization time available for the geology investigation has not yet been determined. The sample types and locations within the exploration zone at a landing site are ranked to aid the planning process, as well as decision making during the mission. Science Evaluation of Potential Landing Sites: The STM also provides a means to compare potential landing sites within the candidate landing regions. The A3GT was tasked with providng a rapid science assessment of the potential landing sites, and developed science figures of merit to based on the sutiability of a site for meeting the geology goals and objectives [7]. Features such as small permanently shadowed regions (PSRs) that have the potential to host water ice in the near surface and rocks that are linked to known soure craters are critical for meeting our highest priority objectives. Also important are the accessibility of those features in terms of distance from the landing site and slope. We find the final site selected will substantially impact how well the STM objectives can be accomplished. A significant fraction of the sites (~one-third) are especially promising for enabling the mission to address key, decadal-level science objectives (see additional details in [7]). Testing and Training: The site-agnostic STM is being incorporated into flight operations planning and software, and is being applied to multiple notional landing sites to refine the investigation plan and test real-time operations. A recently completed exercise included the planning and simulated execution (using virtual reality, VR) of an Artemis-III-like mission at a lunar site. The planning process led to additional ideas on how to operationalize the science traceability matrix and geologic mapping in ways that can be applied to planning for any site in the Artemis candidate landing regions, as well as areas for consolidation and simplification of imaging and sampling plans needed to meet the Artemis III geology objectives. Additional VR and field simulations are currently being planned, and the A3GT recently completed a field exercise that included working with the geology sampling tools (government reference design), the type of camera to be used on Artemis III, and comparisons of geologic understanding based on remote sensing observations, telemetered field observations, and in-person exploration. References: [1] National Academies of Sciences, Engineering, and Medicine (2022) Origins, Worlds, and Life: A Decadal Strategy for Planetary Science and Astrobiology 2023-2032. [2] NASA Headquarters (2023) NASA’s Moon to Mars Strategy and Objectives Development. [3] Hurtado J.M. et al. (2025) Lunar Planet. Sci. Conf 56, Abs. 2747. [4] Borg L. et al. (1999) Geochimica et Cosmochimica Acta, 63, 2679–2691. [5] Borg L.E. et al. (2020) Geochimica et Cosmochimica Acta, 290, 312–332. [6] Heldmann J.L. et al. (2025) Lunar Planet. Sci. Conf. 56, Abs. 2284. [7] Fassett C.I. et al. (2025) Lunar Planet. Sci. Conf. 56, Abs. 2149.