About

Paul Hayne is an astrophysical and planetary sciences professor at the University of Colorado Boulder. His research focuses on terrestrial planet climate and the physics of volatiles on planets, moons, and small bodies such as asteroids and comets. He and his group develop numerical models and analyze data from interplanetary spacecraft and telescopes to better understand planetary surfaces and atmospheres, with an emphasis on present-day active processes. Dr. Hayne is the Principal Investigator for the NASA Lunar Compact Infrared Imaging System (L-CIRiS), which is planned to be the first thermal camera to operate in the Moon’s south polar region. He also serves as the Project Scientist at LASP for the Emirates Mission to the Asteroid Belt and is a Co-Investigator on several active NASA planetary missions, including the Lunar Reconnaissance Orbiter, Lunar-VISE, Mars Reconnaissance Orbiter, and Europa Clipper.

Research topics

• Astrobiology
• Geology
• Environmental science
• Remote sensing
• Atmospheric sciences

Selected publications

• Data (detected boulders, rock abundance maps, and more) for the manuscript "Effect of boulder-size distributions on thermally derived rock abundances on the Moon"

  Zenodo (CERN European Organization for Nuclear Research) · 2026-01-06 · 1 citations

  datasetOpen access
  PublisherDOI

• Morphometric Properties of the CP-21 Landing Site on the Moon at Mons Gruithuisen Gamma

  The Planetary Science Journal · 2026-04-01

  articleOpen access

  Abstract Characterizing terrain surface properties is an essential step in assessing the feasibility of landing successfully at a location on a planetary surface. Slopes and terrain ruggedness index (TRI) values derived from high-resolution (2 m pixel −1 ) digital terrain models provided important constraints in selecting the landing site for the upcoming Payloads and Research Investigations on the Surface of the Moon program as part of the Commercial Lunar Payload Services task order CP-21 mission. The selected landing site needed to balance safety requirements with the ability to achieve the science and exploration goals of the Lunar Vulkan Imaging and Spectroscopy Explorer payload. In this study, we compare several morphometric parameters in the context of the CP-21 landing site on Mons Gruithuisen Gamma, or the Gamma dome, and quantify the information they convey about lunar surface properties to assess their utility for future landing site evaluation. TRI was found to be a useful metric for assessing landing site safety. Metrics that better decouple slope and surface roughness, the vector ruggedness measure and the standard deviation of slope, provided additional information about surface characteristics and textures such as the degree to which roughness is isotropic.

  PublisherDOI

• Thermal Precursors to Regional Dust Storms on Mars: Observations With Mars Climate Sounder

  Journal of Geophysical Research Planets · 2025-11-01

  articleOpen accessSenior author

  Abstract Surface heating by solar flux is an important mechanism in driving atmospheric instability and dust lifting on Mars. We investigated possible signals of elevated surface temperatures and surface flux prior to regional Mars dust storms using Mars Climate Sounder data. With a significant correlation deduced between these precursor signals and the dust storms, the average lag time between the signal peak and storm peak was inferred as 14°–20° L S for an “A” storm and 12°–23° L S for a “C” storm. Based on these derived lag times and the consistency of elevated surface heating, the potential predictability of these storms was analyzed. Using a defined surface flux difference threshold, five of seven “A” storms and six of eight “C” storms were successfully detected. The likelihood of obtaining equal or better detection rates from random sampling was computed to be 87% for “A” storms and 99% for “C” storms, albeit with a false positive rate of 30% for “A” storms. To explore the mechanisms by which these dust storms form, the hypothesis of excess surface heating leading to near‐surface convective instability triggering a positive dynamical feedback loop was postulated. Investigation of this hypothesis using Mars Climate Sounder vertical temperature profiles presented a reasonable correlation between preceding convective instability and regional dust storms. However, due to limitations in vertical resolution and sample size, this hypothesis currently remains inconclusive. Alternative mechanisms involving the potential connection between anomalous excess surface heating and regional dust storm formation are discussed.

  PublisherOA PDFDOI

• Active Inference for Bandit-Based Autonomous Robotic Exploration With Dynamic Preferences

  IEEE Transactions on Robotics · 2025-01-01

  article

  Autonomous selection of optimal options for data collection from multiple alternatives is challenging in uncertain environments. When secondary information about options is accessible, such problems can be framed as contextual multi-armed bandits (CMABs). Neuro-inspired active inference has gained interest for its ability to balance exploration and exploitation using the expected free energy objective function. Unlike previous studies that showed the effectiveness of active inference based strategy for CMABs using synthetic data, this study aims to apply active inference to realistic scenarios, using a simulated mineralogical survey site selection problem. Hyperspectral data from AVIRIS-NG at Cuprite, Nevada, serves as contextual information for predicting outcome probabilities, while geologists' mineral labels represent outcomes. Monte Carlo simulations assess the robustness of active inference against changing expert preferences. Results show active inference requires fewer iterations than standard bandit approaches with real-world noisy and biased data, and performs better when outcome preferences vary online by adapting the selection strategy to align with expert shifts.

  PublisherDOI

• Surface Composition of Asteroid 269 Justitia: Insights from Spectral Mixture Modeling

  The Astrophysical Journal · 2025-10-09 · 2 citations

  articleOpen access

  Abstract Asteroid (269) Justitia is one of the more unusual asteroids in the main belt due to its extremely red spectral slope at visible and near infrared (VNIR) wavelengths. While the surface composition of (269) Justitia remains uncertain due to a lack of diagnostic absorption features in the VNIR region, intriguing clues to its nature are provided by recent mid- and thermal-infrared wavelength observations (MIR and TIR, respectively). In the VNIR, no identifiable analogs to Justitia can be found among the known meteorites. Instead, the best spectral matches come from Trans-Neptunian Objects (TNOs), possibly suggesting a genetic relationship with those bodies. On the other hand, recent TIR emissivity spectra reveal the likely presence of fine-grained anhydrous silicates on Justitia’s surface, possibly inconsistent with a TNO origin. To explore this issue, we used a radiative transfer mixing model to investigate the spectral nature of Justitia in the VNIR and TIR. In the VNIR, our results are consistent with mixtures of space weathered silicates and carbonaceous material, though the presence of complex organics cannot be ruled out. In the TIR, our results favor either carbonaceous material or a mixture of space-weathered silicates and carbonaceous components. The best spectral match to Justitia’s spectra was found by blending carbonaceous material with moderate to extensively space-weathered silicates. This combination could, in turn, indicate a potential collision between silicate-rich and carbonaceous bodies during the early history of Justitia.

  PublisherDOI

• The Lunar-VISE Investigation of Mons Gruithuisen Gamma

  2025-07-09

  preprintOpen access

  Introduction: The Gruithuisen domes (36°N, 40°W) were first identified as volcanic structures distinct from their surrounding mare flows based on their morphology and unusually red-sloped UV-visible spectrum [e.g., 1–3]. Morphologic analyses of the steep-sided domes suggested they are composed of highly viscous magmas similar to terrestrial extrusive volcanic features, which are consistent with higher silica contents (> 52 wt.% SiO2) found in rhyolites, dacites and basaltic andesites [e.g., 4]. Further observations by Lunar Prospector (LP), Diviner Lunar Radiometer (Diviner), and the Lunar Reconnaissance Orbiter Camera (LROC) have shown that the domes are enriched in Th (~17 to 40 ppm) and SiO2, and low in FeO [e.g., 5–7]. However, the exact composition of the rock making up the domes has remained elusive. In particular, Diviner’s compositional bands were not optimized for constraining the composition of highly silicic materials [6,8], making it challenging to constrain how such rocks could form on a single plate planetary body like the Moon.Mission Objectives: The Lunar Vulkan Imaging and Spectroscopy Explorer (Lunar-VISE) instrument suite was selected through NASA’s Payloads and Research Investigations on the Surface of the Moon (PRISM) program and will be deployed on the Moon by Firefly Aerospace, which was selected through NASA’s Commercial Lunar Payload Services (CLPS) program for task order CP-21. Lunar-VISE will land on Mons Gruithuisen Gamma (hereafter referred to informally as “the Gamma dome”) and will use its combined lander and rover payload to determine the composition and physical properties of the rocks and regolith comprising the domes, placing critical constraints on their formation mechanism.The overarching science goal of our investigation is to understand how late-stage lunar silicic volcanism works under lunar conditions, as typified by the Gruithuisen domes. This goal will be accomplished through two science objectives that place critical constraints on the two main hypotheses for the formation of non-mare silicic volcanic constructs by (1) mapping spatial variations in composition along multiple traverses across the landing site, and correlating the measured variations to rock and regolith properties, surface features, and dome morphology. Lunar-VISE will also (2) relate those local-scale measurements to orbital remote sensing observations from previous and current spacecraft. Our primary exploration goal is to understand the geotechnical properties of the lunar regolith on the domes at the lander/rover scale. This exploration goal will be accomplished by mapping local variations in regolith properties of the region surrounding the landing site and along the rover’s traverse.Lunar-VISE Instrument Suite: To achieve our goals and objectives, Lunar-VISE includes a complementary suite of heritage instruments on a rover and lander. The rover payload includes two separate units, the Lunar-VISE Visible/Infrared Multiband Suite (LV-VIMS) and the Gamma-Ray and Neutron Spectrometer (LV-GRNS). The lander suite includes two additional cameras for characterizing the landing site, surrounding area, and rover traverse: the Lunar-VISE Descent Camera (LV-DC) for surface imaging during landing, and the Lunar-VISE Context Camera (LV-CC) for panoramas up to 270° around the landing site and the rover traverse. Both cameras are copies of the LV-VIC but without the multispectral capabilities.Current Mission Status: The Lunar-VISE team passed NASA CDR in January/February 2024 and KDP in March 2024. Instrument building, integration, and environmental testing of the Lunar-VISE payload instruments is currently underway. Delivery in place is on schedule and currently planned for fall 2025. With the recent selection of Firefly Aerospace as the CLPS provider for CP-21, the Lunar-VISE team will begin working with Firefly and Honeybee Robotics to integrate the payload instruments onto the lander and rover and further develop surface operation plans.Acknowledgments: Lunar-VISE is funded through NASA’s PRISM2 cooperative agreement number 80NSSC22M0303. Thanks to our Mission Manager C. Benson, Program Scientist R. Watkins, Project Scientist M. Banks, CLPS Integration Manager J. Schonfeld, and NASA HQ and PMPO teams.References: [1] Head J. W. and McCord T. B. (1978) Science, 199, 1433-1436. [2] Bruno B. C. et al. (1991) LPSC XXI, 405-415. [3] Chevrel S. D. et al. (1999) JGR, 104, 16515-16529. [4] Wilson L. and Head J. W. (2003) JGR Planets, 108(E2), 5012. [5] Hagerty J. J. et al. (2006) JGR, 111, doi:10.1029/2005JE002592. [6] Glotch T. D. et al. (2010) Science, 329, 1510-1513. [7] Clegg-Watkins R. N. (2017) Icarus, 285, 169-184. [8] Greenhagen B. T. et al. (2010) Science, 329, 1507-1509.

  PublisherDOI

• Atmospheric CO ₂ Ice in the Martian Polar Regions: Physical and Spectral Properties From Mars Climate Sounder Observations

  Journal of Geophysical Research Planets · 2025-07-01

  articleOpen access

  Abstract ice clouds are important for polar energy balance and the carbon dioxide cycle on Mars. However, uncertainties remain regarding their physical and radiative properties, which control how polar clouds interact with the global Martian climate. Here, we use Mars Climate Sounder (MCS) observations of atmospheric radiance to estimate these physical and radiative properties. We find that Martian clouds are typically composed of large particles from a narrow size distribution with an effective radius of 46 m and an effective variance of in the southern hemisphere, and an effective radius of 42 m and an effective variance of in the north. The similarity in sizes of ice particles in both hemispheres may be due to the fact that clouds tend to form near the same pressure level in each hemisphere, despite the higher surface pressures in the north. We use a simplified convective cooling model to show that the small effective variance we derive may be a consequence of the fact that is also the dominant atmospheric constituent on Mars, which allows ice particles to reach sizes upwards of 10 m within seconds. At the same time, the fact that the Martian atmosphere is so thin means that large particles fall rapidly to the surface, reducing the range of particle sizes that can remain in the atmosphere for any extended period of time. This study is part of ongoing work to add ice opacity profiles to the MCS retrieval pipeline.

  PublisherDOI

• Science Overview of the Emirates Mission to the Asteroid Belt

  2025-07-09 · 2 citations

  preprintOpen access

  The Emirates Mission to the Asteroid Belt (EMA) is set to launch in 2028 to conduct a tour of main belt asteroids. Over a seven-year period, EMA will perform six distinct asteroid flybys and rendezvous with a final seventh asteroid called (269) Justitia, a 54-km diameter object with a uniquely reddened spectrum. The flyby targets consist of a diverse collection of asteroids including (623) Chimaera, the largest remnant of the primitive C-type Chimaera family, and members of the Baptistina, Eos, Erigone, and Euterpe families. Five of the seven targets are C-complex, which form a key piece of the puzzle of early solar system formation and its dynamical evolution. The primary science goal is to probe the origin and evolution of water-rich asteroids, with a focus on three main questions: 1) Where did the volatile-rich asteroids form? 2) Are these asteroids linked to specific meteorites? 3) What does their chemical inventory and volatile abundances tell us about main belt evolution? To answer these questions, the mission will perform science investigations based on the following objectives: A) Determine the geologic history and volatile content of multiple main belt asteroids and investigate the interior structure of the rendezvous target. B) Determine temperatures and thermophysical properties on multiple asteroids to assess their surface evolution and volatile histories. The EMA remote sensing instruments include: 1) Visible color narrow-angle camera (CNAC), 2) Midwave infrared spectrometer (MIST-A), 3) Thermal IR spectrometer (EMBIRS), and thermal IR camera (IR-Cam). MIST-A is provided by the Agenzia Spaziale Italiana (ASI) in partnership with the Italian National Institute for Astrophysics (INAF) and Leonardo S.p.A. The CNAC and IR-cam will be provided by Malin Space Science Systems, and EMBIRS will be provided by Northern Arizona University and Arizona State University. The spectral coverage of the multiple infrared instruments is expected to span 2.0 to > 100 µm, providing opportunities for detailed compositional and thermophysical analyses. Visible images with few meters/pixel resolution will be acquired for (269) Justitia, along with thermal infrared images with 10-100 m/pixel resolution.Funding of the Emirates Mission to the Asteroid Belt is provided by the UAE Space Agency with support from the University of Colorado Boulder’s Laboratory for Atmospheric and Space Physics as its main knowledge partner. Figure 1: Overview of the EMA instrument suite.

  PublisherDOI

• Titan's surface composition

  Elsevier eBooks · 2025-01-01 · 2 citations

  book-chapter
  PublisherDOI

• The Emirates Main Belt Infrared Spectrometer (EMBIRS) onboard the Emirates Mission to the Asteroid Belt

  2025-07-09

  preprintOpen access

  The Emirates Main Belt Infrared Spectrometer (EMBIRS), one of four remote sensing instruments onboard the Emirates Mission to the Asteroid Belt (EMA), is designed to collect data on six main-belt asteroid flybys, ending with proximity operations at 269 Justitia. EMBIRS will measure the emitted spectral radiance of these asteroids providing constraints on the thermophysical properties and spectral character/composition of these asteroids. In combination with the other instruments on the EMA payload, EMBIRS will address the key goals of the mission, specifically evaluating the origins and evolution of water-rich asteroids and their resource potential. EMBIRS measurements address several mission science objectives, including mapping the silicate mineralogy of compositionally diverse, water-rich asteroids, supporting the evaluation of their geologic history, and characterizing the temperature and thermophysical properties of multiple asteroids to assess their formation, surface evolution, and volatile histories.The EMBIRS instrument is an interferometric thermal infrared spectrometer developed and provided by Northern Arizona University (NAU) and Arizona State University (ASU) in partnership with the University of Colorado Boulder’s Laboratory for Atmospheric and Space Physics for inclusion on the United Arab Emirates Space Agency’s EMA mission. It builds on a long heritage of thermal infrared spectrometers designed, built, and managed by ASU's Mars Space Flight Facility. EMBIRS is most directly akin to the Emirates Mars Infrared Spectrometer (EMIRS) on the Emirates Mars Mission (EMM). EMBIRS is a build to print of EMIRS except for minor modifications to the mechanical and thermal interfaces (Figures 1 & 2). EMBIRS is 53x29x32 cm, has a mass of ~12.7 kg, and requires 21 W during operational activities. EMBIRS collects spectral data from 6-40+ µm at 10 and 20 cm-1 spectral sampling. This instrument utilizes an on-axis deuterated L-alanine doped triglycine sulfate (DLaTGS) detector and a scan mirror to make infrared radiance measurements of the asteroids during flybys and 269 Justitia proximity operations.Under the current concept of operations, EMBIRS achieves complete global coverage (daytime and nighttime observations) of 269 Justitia within 8 weeks of observing with pixel sizes of

  PublisherDOI

Frequent coauthors

• D. A. Paige

  University of California, Los Angeles

  170 shared

• B. T. Greenhagen

  102 shared

• S. Fornasier

  95 shared

• M. A. Barucci

  Sorbonne Paris Cité

  94 shared

• J. L. Bandfield

  Space Science Institute

  87 shared

• P. H. Hasselmann

  Astronomical Observatory of Rome

  79 shared

• M. Fulchignoni

  Sorbonne Université

  79 shared

• J. P. Williams

  Planetary Science Institute

  77 shared

Education

• PhD, Earth, Planetary and Space Sciences

  University of California Los Angeles

  2010

• MS, Geophysics

  Stanford University

  2005

• BS, Geophysics

  Stanford University

  2003