Sazuna/UAT_keywords huggingface dataset:
The Mars Orbiter for Resources, Ices, and Environments (MORIE) Science Goals and Instrument Trades in Radar, Imaging, and Spectroscopy. The Mars Orbiter for Resources, Ices, and Environments (MORIE) was selected as one of NASA's 2019 Planetary Mission Concept Studies. The mission builds upon recent discoveries and current knowledge gaps linked to two primary scientific questions: (1) when did elements of the cryosphere form and how are ice deposits linked to current, recent, and ancient climate, and (2) how does the crust record the evolution of surface environments and their transition through time? Addressing these questions has emerged in numerous recent reports as a high priority in investigating the evolution of Mars as a habitable world. A subsidiary goal of the mission concept is to provide information relevant to the eventual human exploration of Mars, specifically helping to locate and quantify near-surface water ice and hydrated mineral resources. The proposed instrument suite includes polarimetric synthetic aperture radar imaging, radar sounding, high-resolution visible and infrared imaging, both short-wave and thermal-infrared spectroscopy, and multichannel wide-angle imaging. MORIE would provide novel measurements of Mars expected to lead to significant new discoveries by the first radar imaging from orbit, radar sounding directly over the poles, and mineral mapping at spatial scales that will unravel geologic sequence stratigraphy through time. The final report of the mission concept provides details on the spacecraft, orbital design, technological maturity, results from systems-level integration studies, and costs. This article is intended to expand upon the science motivation for the mission, the measurement goals and objectives, and the instrument trade space that was examined in detail during the concept study.

Keywords: Radar astronomy, Space vehicle instruments, Mars, Spectroscopy
The Enceladus Orbilander Mission Concept: Balancing Return and Resources in the Search for Life. Enceladus's long-lived plume of ice grains and water vapor makes accessing oceanic material readily achievable from orbit (around Saturn or Enceladus) and from the moon's surface. In preparation for the National Academies of Sciences, Engineering and Medicine 2023-2032 Planetary Science and Astrobiology Decadal Survey, we investigated four architectures capable of collecting and analyzing plume material from orbit and/or on the surface to address the most pressing questions at Enceladus: Is the subsurface ocean inhabited? Why, or why not? Trades specific to these four architectures were studied to allow an evaluation of the science return with respect to investment. The team found that Orbilander, a mission concept that would first orbit and then land on Enceladus, represented the best balance. Orbilander was thus studied at a higher fidelity, including a more detailed science operations plan during both orbital and landed phases, landing site characterization and selection analyses, and landing procedures. The Orbilander mission concept demonstrates that scientifically compelling but resource-conscious Flagship-class missions can be executed in the next decade to search for life at Enceladus.

Keywords: Natural satellite surfaces, Remote sensing, Astrobiology, Planetary science, Biosignatures, Saturnian satellites
Tilting Uranus: Collisions versus Spin-Orbit Resonance. In this paper, we investigate whether Uranus's 98° obliquity was a by-product of a secular spin-orbit resonance assuming that the planet originated closer to the Sun. In this position, Uranus's spin precession frequency is fast enough to resonate with another planet located beyond Saturn. Using numerical integration, we show that resonance capture is possible in a variety of past solar system configurations but that the timescale required to tilt the planet to 90° is of the order ∼108 yr—a time span that is uncomfortably long. A resonance kick could tilt the planet to a significant 40° in ∼107 yr only if conditions were ideal. We also revisit the collisional hypothesis for the origin of Uranus's large obliquity. We consider multiple impacts with a new collisional code that builds up a planet by summing the angular momentum imparted from impactors. Because gas accretion imparts an unknown but likely large part of the planet's spin angular momentum, we compare different collisional models for tilted, untilted, spinning, and nonspinning planets. We find that a 1 M⊕ strike is sufficient to explain the planet's current spin state, but that two 0.5 M⊕ collisions produce better likelihoods. Finally, we investigate hybrid models and show that resonances must produce a tilt of at least ∼40° for any noticeable improvements to the collision model. Because it is difficult for spin-orbit resonances to drive Uranus's obliquity to 98° even under these ideal conditions, giant impacts seem inescapable.

Keywords: Neptune, Solar system planets, Orbits, Orbital resonances, Celestial mechanics, N-body simulations, Planet formation, Uranus
The Inner Solar System Chronology (ISOCHRON) Lunar Sample Return Mission Concept: Revealing Two Billion Years of History. We present the Inner SOlar System CHRONology (ISOCHRON) concept to return samples of the youngest extensive mare basalt for age-dating and geochemical analysis. The young basalt is exposed at a site southwest of Aristarchus Plateau, for which complete remote-sensing data are available for thorough landing site analysis. Data from these samples would revolutionize the ability to assign exposure ages to rocky planetary surfaces based on the samples returned by Apollo and Luna. Their petrology and geochemistry will enable assessment of the most recent voluminous lunar magmatism. Regolith evolution and mixing models such as ballistic sedimentation would be directly testable to provide crucial ground truth that would enhance the science value of current and future remotely sensed data sets. ISOCHRON's science goals support NASA's Artemis program to return to the Moon and its related robotic programs currently in planning.

Keywords: Lunar petrology, Lunar craters, Planetary probes, Lunar geochronology, Planetary science
Understanding the Lunar Nearside-Farside Dichotomy via In Situ Trace Element Measurements: The Scientific Framework of a Prospective Landed Mission. Trace elements, distinguished by their low abundances (parts per million by weight (ppmw)), track local, regional, and planetary-scale processes in samples sourced from throughout the solar system. Such analyses of lunar samples have provided insights on its surface rocks and interpretations of its deep interior. However, returned samples, sourced from the lunar nearside, cannot be used to address processes responsible for the morphological dichotomy between the lunar nearside and farside. The hemispherical dichotomy points to distinct evolutionary histories of these two domains, rendering our understanding of lunar history incomplete. We outline the scientific justification for a landed, in situ investigation of lunar farside lithologies, focusing on chemical analyses that will constrain the Moon's bi-hemispherical chemical evolution. Newly developed and heritage spaceflight instruments, capable of measuring low element abundances (limits of detection &lt;10 ppmw ± 20%), can be deployed on the lunar farside and provide constraints on (1) the temperature and pressure of mare basalt crystallization, (2) depth-dependent mineralogical and compositional changes in the lunar mantle, (3) the chronology of major geologic events, and (4) abundances and distributions of refractory and heat-producing elements of the lunar farside mantle. The science return and logistical challenges of targeting four specific landing sites on the lunar farside are identified: Moscoviense, Apollo, Von Kármán, and Leibnitz craters. These sites maximize impact melt basin lithologies and later mare magmatism, and they minimize terrain hazards.

Keywords: Earth-moon system, Mantle
Deep, Closely Packed, Long-lived Cyclones on Jupiter's Poles. The Juno mission to Jupiter has found closely packed cyclones at the planet's two poles. The observation that these cyclones coexist in very confined space, with outer rims almost touching each other but without merging, poses a big puzzle. In this work, we present numerical calculations showing that convectively sustained, closely packed cyclones can form and survive without merging for a very long time in the polar region of a deep rotating convection zone (for thousands of planetary rotation periods). Through an idealized application of the inertial stability criterion for axisymmetric circulations, it is found that the large Coriolis parameter near the pole plays a crucial role in allowing the cyclones to be packed closely.

Keywords: Planetary atmospheres, Solar system gas giant planets, Jupiter
Validation of Stereophotoclinometric Shape Models of Asteroid (101955) Bennu during the OSIRIS-REx Mission. NASA's OSIRIS-REx mission to asteroid (101955) Bennu relied on the production of real-time shape models for both spacecraft navigation and scientific analysis. The primary method of constructing shape models during the early phases of the mission was image-based stereophotoclinometry (SPC). The SPC shape models were used for operational planning, navigation, sample site selection, and initial scientific investigations. To this end, detailed analyses of the quality of each shape model and a thorough documentation of all sources of error were vital to ensure proper considerations of the limitations of each model. In this paper, we present methods used during the OSIRIS-REx mission to validate the SPC shape models and construct the associated quality reports. Although developed for the OSIRIS-REx mission, these validation techniques can be applied to SPC-derived shape models of other planetary bodies.

Keywords: Small Solar System bodies, Near-Earth objects, Asteroids
Dione's Wispy Terrain: A Cryovolcanic Story?. We examine the H2O ice phase on the surface of Dione, one of Saturn's icy satellites, to investigate whether it might harbor cryovolcanic activity induced by a subcrustal body of water. Several studies have searched for such a signature, as summarized in Buratti et al.; however, none has yet produced sufficient evidence to dissipate doubts. In the radiation environment characteristic of Saturn's icy moons, the presence of crystalline H2O ice has been used as a marker of a high-temperature region. Because ion bombardment will, over time, drive crystalline ice toward an increasingly amorphous state, the current phase of the H2O ice can be used to gauge the temporal temperature evolution of the surface. We adopt a technique described by Dalle Ore et al. to map the fraction of amorphous to crystalline H2O ice on Dione's surface, observed by the Cassini Visible and Infrared Mapping Spectrometer, and provide an ice exposure age. We focus on a region observed at high spatial resolution and centered on one of the faults of the Wispy Terrain, which is measured to be fully crystalline. By assuming an amorphous to crystalline ice fraction of 5% (i.e., 95% crystallinity), significantly higher than the actual measurement, we obtain an upper limit for the age of the fault of 152 Ma. This implies that the studied fault has been active in the last ∼100 Ma, supporting the hypothesis that Dione might still be active or was active a very short time ago, and similarly to Enceladus, might still be harboring a body of liquid water under its crust.

Keywords: Surface processes, Surface ices, Saturnian satellites
Science-rich Sites for In Situ Resource Utilization Characterization and End-to-end Demonstration Missions. Within the European Space Agency's "Commercial In Situ Resource Utilization (ISRU) Demonstration Mission Preparation Phase," we examined two types of lunar sites in preparation for an ISRU demonstration mission. First, we considered poorly characterized potential resource sites. For these so-called characterization sites, precursor missions would investigate the material properties and address strategic knowledge gaps for their use as ISRU feedstock. Regions of interest for characterization missions include the Aristarchus plateau, Montes Harbinger/Rimae Prinz, Sulpicius Gallus, and Rima Bode. Regional pyroclastic deposits at the Aristarchus plateau and adjacent Montes Harbinger/Rimae Prinz exhibit remotely sensed low-Ti, high-Fe2+ compositions. They differ from the high-Ti pyroclastics at Rima Bode and Sulpicius Gallus, which are similar to the pyroclastics northwest of the Taurus Littrow valley (Apollo 17 site). Thus, exploration of the Aristarchus plateau would allow investigation of previously uncharacterized materials, whereas Rima Bode or Sulpicius Gallus would allow comparison to Apollo 17 pyroclastics. Any of these sites would enable evaluation of reported H2O/OH in these deposits. Second, we examined a possible site for a direct ISRU demonstrator mission. For a stand-alone end-to-end (E2E) ISRU demonstrator, a fuller understanding of the physical and compositional characteristics of potential feedstock is required for mission risk reduction. In this case, locations near preexisting sites would allow extrapolation of ground truth to nearby deposits. Because a Ti-rich pyroclastic deposit appears advantageous from beneficiation and compositional perspectives, we examine an example E2E demo site northwest of the Taurus Littrow valley. Hydrogen and methane reduction, as well as the Fray-Farthing-Chen Cambridge process, could be tested there.

Keywords: Lunar surface, Lunar science
Erosion of Volatiles by Micrometeoroid Bombardment on Ceres and Comparison to the Moon and Mercury. Ceres, the largest reservoir of water in the main belt, was recently visited by the Dawn spacecraft, which revealed several areas bearing H2O-ice features. Independent telescopic observations showed a water exosphere of currently unknown origin. We explore the effects of meteoroid impacts on Ceres by considering the topography obtained from the Dawn mission using a widely used micrometeoroid model and ray-tracing techniques. Meteoroid populations with 0.01-2 mm diameters are considered. We analyze the short-term effects Ceres experiences during its current orbit, as well as long-term effects over the entire precession cycle. We find that the entire surface is subject to meteoroid bombardment, leaving no areas in permanent shadow with respect to meteoroid influx. The equatorial parts of Ceres produce 80% more ejecta than the polar regions due to the large impact velocity of long-period comets. Mass flux, energy flux, and ejecta production vary seasonally by a factor of 3-7 due to the inclined eccentric orbit. Compared to Mercury and the Moon, Ceres experiences significantly smaller effects of micrometeoroid bombardment, with a total mass flux of 4.5 ± 1.2 × 10-17 kg m-2 s-1. On average, Mercury is subjected to a 50× larger mass flux and generates 700× more ejecta than Ceres, while the lunar mass flux is 10× larger and the ejecta generation is 30× larger than on Ceres. For these reasons, we find that meteoroid impacts are an unlikely candidate for the production of a water exosphere or significant excavation of surface features. The surface turnover rate from the micrometeoroid populations considered is estimated to be 1.25 Myr on Ceres.

Keywords: Impact phenomena, Micrometeoroids, Meteoroids, Space weather, The Moon, Meteoroid dust clouds, Mercury (planet), Zodiacal cloud
Latitudinal Distribution of Ethane Precipitation on Titan Modulated by Topography and Orbital Forcing and Its Implication for Titan's Surface Evolution. A general circulation model with geography constrained by Cassini is used to predict how ethane precipitation in Titan's lower stratosphere varies with latitude, season, and orbital forcing over the past 100 kyr. Ethane precipitation is generally more prevalent near the winter pole, where stratospheric ethane is transported downward toward the cold trap, and this general pattern is relatively insensitive to orbital parameter variations and geography. However, eccentricity-driven seasonal temperature variations modulate the seasonal asymmetry of ethane precipitation to some extent. The annual ethane precipitation does not monotonically increase from equator to pole but maximizes at selected sites, preferentially over empty deep basins such as Hagal Planitia. Local enhancement of ethane precipitation is caused by katabatic winds from plateau to basin and an associated regional-scale thermally direct circulation over the slope, which induces strong adiabatic cooling near the tropopause. The observed putative ethane clouds off the poles are evidence that ethane condensation is affected by topography. Preferential ethane precipitation over basins may increase the irregularity of Titan's shape by isostatic crustal subsidence after substitution of enclathrated methane by percolated ethane.

Keywords: Planetary atmospheres, Planetary surfaces, Saturnian satellites
Some New Results and Perspectives Regarding the Kuiper Belt Object Arrokoth's Remarkable, Bright Neck. One of the most striking and curious features of the small Kuiper Belt Object (KBO), Arrokoth, explored by New Horizons is the bright, annular neck it exhibits at the junction between its two lobes. Here we summarize past reported findings regarding the properties of this feature and then report new results regarding its dimensions, reflectivity and color, shape profile, and lack of identifiable craters. We conclude by enumerating possible origin scenarios for this unusual feature. New results include a new estimated measurement of the observed neck area of 8 ± 1.5 km2, a total neck surface area of 32 km2, a 12.5:1 ratio of circumference to height, a normal reflectance histogram of the observed neck, and the fact that no significant (i.e., &gt;2σ) neck color units were identified, meaning the neck's color is generally spatially uniform at the 1.5 km pixel-1 scale of the best color images. Although several origin hypotheses for the bright material in the neck are briefly discussed, none can be conclusively demonstrated to be the actual origin mechanism at this time; some future tests are identified.

Keywords: Small Solar System bodies, Kuiper belt, Classical Kuiper belt objects, Comet surfaces, Trans-Neptunian objects, Flyby missions
Latitude Variation of Flux and Impact Angle of Asteroid Collisions with Earth and the Moon. Flux and impact angles were calculated for asteroid collisions with Earth and the Moon, using the latest population models for the distribution of near-Earth objects (NEOs) and precession models to determine the impact probabilities. The calculations predict that the flux of impacts to the poles for Earth is 22% greater than the flux at the equator, and 55% greater for the Moon. Impacts near the equator typically have shallower impact angles with a mode near 30° above the horizontal. Conversely, impacts near the poles are typically steep with a mode close to 65°. Our new analysis updates the previously published results by Le Feuvre &amp; Wieczorek incorporating: (1) an updated debiased distribution of NEOs, and (2) updated collision probabilities that account for Lidov-Kozai precession. The new impact distributions provide an important update to risk models, showing a 7% increase in average population risks from sub-300 m impactors, compared to previous atmospheric entry distributions, mostly due to faster impact velocities.

Keywords: Impact phenomena, Near-Earth objects, Lunar craters, Meteor radiants, Lunar impacts
Tidal Heating Did Not Dry out Io and Europa. The Galilean satellites exhibit a clear trend in composition from the rocky Io, close to Jupiter, to the icy and distant Callisto. Proposed causes of this trend can be roughly divided by when the trend developed—either as a result of the material accreted, as a byproduct of the accretion process, or due to the subsequent diverging evolution of the moons. While the first two options have been heavily favored in the existing literature and were therefore studied previously, in this work, we directly address the last of these possibilities. To do so, we determine the range of plausible tidal heating experienced by these moons and how efficiently that energy could be converted into mass loss. We find that while the total tidal energy does exceed the energy required to lose an ice shell, the loss process would have to be highly energy efficient. Examining a range of loss processes, we find that only in extreme cases could enough mass be lost from Europa and no cases where enough mass could be lost from Io. We conclude that this compositional gradient must have been in place by the end of accretion.

Keywords: Planetary science, Galilean satellites, Planetary atmospheres, Planetary structure
Col-OSSOS: The Distinct Color Distribution of Single and Binary Cold Classical KBOs. The cold classical Kuiper Belt Objects (KBOs) possess a high, ≳30% binary fraction. Widely separated and dynamically fragile, these binary systems have been useful in tracing the origins of KBOs. A new class of binaries was recently identified by their colors. The so-called blue binaries are unanimously members of the less red compositional class, and exhibit a 100% binary fraction. They appear to be push-out survivors, emplaced in the classical region during Neptune's phases of outward migration. The presence of these binary systems implies that the majority of objects that formed near the cold classical region formed as binaries. Here we present new optical color measurements of cold classical KBOs from the Colors of the Outer Solar System Origins Survey, including colors of a blue binary discovered by the Solar System Origins Legacy Survey—2015 RJ277. The increased size of the colors sample has resulted in order-of-magnitude decrease in the probability that the binaries and singles sample share the same color distribution. From the Anderson-Darling statistic, this probability is only a 0.3%, while it is only 0.002% when utilizing the difference of means statistic. We find a hint that the blue binaries have inflated free inclinations compared to their red counterparts, consistent with the push-out origin for these bodies.

Keywords: Solar system, Kuiper belt, Trans-Neptunian objects
Pluto's Haze Abundance and Size Distribution from Limb Scatter Observations by MVIC. The New Horizons spacecraft observed Pluto and Charon at solar-phase angles between 16° and 169°. In this work, we use the Multispectral Visible Imaging Camera (MVIC) observations to construct multiwavelength phase curves of Pluto's atmosphere, using the limb scatter technique. Observational artifacts and biases were removed using Charon as a representative airless body. The size and distribution of the haze particles were constrained using a Titan fractal aggregate phase function. We find that monodispersed and log-normal populations cannot simultaneously describe the observed steep forward scattering, indicative of wavelength-scale particles, and the non-negligible backscattering indicative of particles much smaller than the wavelength. Instead, we find it necessary to use bimodal or power-law distributions, especially below ∼200 km, to properly describe the MVIC observations. Above 200 km, where the atmosphere is isotropically scattering, a monodisperse, log-normal, or a bimodal/power law approximating a monodispersed population is able to fit the phase curves well. As compared to the results of previously published articles, we find that Pluto's atmosphere must contain haze particle number densities an order of magnitude greater for small (∼10 nm) and large (∼1 μm) radii, and relatively fewer intermediate sizes (∼100 nm). These conclusions support a lower aggregate aerosol growth rate than that found by Gao et al., indicating a higher charge-to-radius ratio, upwards of 60e- μm-1. In order to generate large particles with a lower growth rate, the atmosphere must also have a lower sedimentation velocity (&lt;∼0.01 m s-1 at 200 km), which is possible with a fractal dimension of less than 2.

Keywords: Phase angle, Planetary atmospheres, Radiative transfer equation, Planetary science, Pluto, Atmospheric composition