cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.48577/jpl.m5svtg
title: Thermophysical evolution of planetesimals in the Primordial Disk

description: The Primordial Disk of small icy planetesimals, once located at 15–30AU from the Sun, was disrupted by giant planet migrationin the early Solar System. The Primordial Disk thereby became the source region of objects in the current–day Kuiper Belt, Scattered Disk, and Oort Cloud. I present the thermophysics code “Numerical Icy Minor Body evolUtion Simulator”, or NIMBUS, and use it to study the thermophysical evolution of planetesimals in the Primordial Disk prior to its disruption. Such modelling is mandatory in order to understand the behaviour of dynamically new comets from the Oort Cloud, as well as the activity of Centaurs and short–period comets from the Scattered Disk, that return pre–processed to the vicinity of the Sun. I find that bodies in the midst of the Primordial Disk with diameters ranging 4–200 km lost all their CO ice on time-scales of order 0.1–10 Myr depending on size, through a combination of protosolar and long–lived radionuclide heating. CO and other hypervolatiles therefore require a less volatile host for their storage. I consider two possible hosts: amorphous water ice and CO2 ice. Because of the high luminosity of the protosun, some Primordial Disk bodies may have sustained significant crystallisation, CO : CO2 segregation, and CO2 sublimation in the uppermost few tens of meters. I discuss how this may affect coma abundance ratios and distant activity in dynamically new comets.
DOI: 10.48577/jpl.onjic3
title: SpiKeS: Precision Warm Spitzer Photometry of the KeplerField

description: The∼200,000 targets monitored for photometric variability during the Kepler prime mission include the best-studied group of stars in the sky, due both to the extensive time history provided by Kepler and to the substantial amounts of ancillary data provided by other investigators or compiled by the Kepler team. To complement this wealth of data, we have surveyed the entire Kepler field using the 3.6and 4.5μm bands of the Warm Spitzer Space Telescope, obtaining photometry in both bands for almost170,000 objects. We demonstrate relative photometric precision ranging from better than ∼1.5% for the brighter stars down to slightly greater than ∼2% for the faintest stars monitored by Kepler. We describe the data collection and analysis phases of this work and identify several stars with large infrared excess, although none that is also known to be the host of an exoplanetary system. The final catalog resulting from this work will be available at the NASA Exoplanet Archive.
DOI: 10.48577/jpl.psdbof
title: Seasonal and interannual variability of sea surface salinity near major river mouths of the world ocean inferred from gridded satellite and in-situ salinity products

description: Large rivers are key components of the land-ocean branch of the global water and biogeochemical cycles. River discharges can have important influences on physical, biological, optical, and chemical processes in coastal oceans. It is therefore of importance to routinely monitor the time-varying dispersal patterns of river plumes. The ESA Soil Moisture and Ocean Salinity (SMOS) and the NASA Soil Moisture Active Passive (SMAP) satellites provide Sea Surface Salinity (SSS) observations capable of characterizing the spatial and temporal variability of major river plumes. The main objective of this study is to examine the consistency of SSS products from these two missions and two in-situ gridded salinity products in depicting SSS variations on seasonal to interannual time scales within a few hundred kilometers of major river mouths. We show that SSS from SMOS and SMAP satellites have good consistency in depicting seasonal and interannual SSS variations near major river mouths. The two gridded in-situ products underestimate these variations substantially. This underestimation, most notably associated with the low SSS season following the high-discharge season, is attributable to the limited in-situ sampling of the river plumes when they are the most active. This work underscores the importance of using satellite SSS to study river plumes as well as to evaluate and constrain models.
DOI: 10.48577/jpl.stuq1u
title: Soil Thermophysical Properties near the InSight Lander Derived from 50 Sols of 1 Radiometer Measurements

description: A subset of the measurements from the InSight lander radiometer acquired shortly after landing is used to characterize the thermophysical properties of the martian soil in Homestead hollow. This dataset is unique as it stems from a high measurement cadence fixed platform studying a simple well-characterized surface, and it benefits from the environmental characterization provided by other instruments. We focus on 8-12 μm observations acquired before the arrival of a regional dust storm (near Sol 50), on the furthest observed patch of soil (i.e., ~4.5 m away) where temperatures are least impacted by the radiative/reflective presence of the lander and where the soil has been least disrupted during landing. The diurnal temperature cycles are adequately fit within error bars using a homogenous regolith configuration with a thermal inertia of 183 ± 25 J m-2 K-1 s-1/2 and a thermometric albedo of 0.17, corresponding to fine sand with the vast majority of particles smaller than 140 µm. A pre-landing assessment leveraging orbital thermal infrared data is consistent with these results, but our analysis of the full diurnal temperature cycle acquired from the ground further indicates that any surficial layering must be thin (i.e., typically within the top few mm) and deep layering must be at least below ~4 cm. The low thermal inertia value indicates limited regolith cementation within the upper one or two skin depth (i.e., ~4-8 cm and more), with cement volumes &lt;&lt;1%, which is challenging to reconcile with visible imagery of two vertical pits.
DOI: 10.48577/jpl.tcfaru
title: The Science Case for a Return to Enceladus

description: The plume of Enceladus is unique in the solar system in providing direct access to fresh material from an extraterrestrial subsurface ocean. The Cassini Mission, though not specifically designed for it, was able to take advantage of the plume to conduct the best characterization to date of an extraterrestrial ocean. Evidence gathered from multiple instruments points to a global, subsurface liquid water ocean rich in salts and organic compounds, with water-rock interactions occurring presumably in hydrothermal systems at or below the moon’s seafloor. Meeting the criteria of “extended regions of liquid water, conditions favorable for the assembly of complex organic molecules, and energy source(s) to sustain metabolism” (Des Marais et al., 2008), the ocean of Enceladus can therefore be considered habitable (e.g., McKay et al., 2008, 2014; Hendrix et al., 2019; Cable et al., 2020). It is also the only confirmed place beyond the Earth where we can easily sample fresh material from a demonstrably habitable environment without the complications of digging or drilling. The next step is to investigate whether Enceladus’ ocean is actually inhabited. Here, we summarize the evidence for Enceladus’ ocean and its habitability, identify constraints and outstanding questions on the detectability of life within its ocean, and recommend a return to Enceladus with a dedicated search-for-life mission (or missions).
DOI: 10.48577/jpl.qjcmvm
title: The Core Mass Function in the Orion Nebula Cluster Region: What Determines the Final Stellar Masses?

description: Applying dendrogram analysis to the CARMA-NRO C18O (J=1–0) data having an angular resolution of 8′′, we identified 692 dense cores in the Orion Nebula Cluster (ONC) region. Using this core sample, we compare the core and initial stellar mass functions in the same area to quantify the step from cores to stars. About 22 % of the identified cores are gravitationally bound. The derived core mass function (CMF) for starless cores has a slope similar to Salpeter’s stellar initial mass function (IMF) for the mass range above 1 M⊙, consistent with previous studies. Our CMF has a peak at a subsolar mass of 0.1 M⊙, which is comparable to the peak mass of the IMF derived in the same area. We also find that the current star formation rate is consistent with the picture in which stars are born only from self-gravitating starless cores. However, the cores must gain additional gas from the surroundings to reproduce the current IMF (e.g., its slope and peak mass), because the core mass cannot be accreted onto the star with a 100% efficiency. Thus, the mass accretion from the surroundings may play a crucial role in determining the final stellar masses of stars.
DOI: 10.48577/jpl.tczguh
title: Dynamics of large effusive eruptions driven by caldera collapse

description: The largest eusive basaltic eruptions are associated with caldera collapse and are manifest 8 through quasi-periodic ground displacements and moderate sized earthquakes[1, 2, 3], yet the 9 mechanism governing their dynamics remains elusive. In this work we provide a new physical 10 model to understand these processes, which accounts for both the quasi-periodic stick-slip 11 collapse of the caldera roof and the long term eruptive behaviour. We show that it is the 12 caldera collapse itself that sustains large eusive eruptions, and that triggering caldera collapse 13 requires, in turn, topography generated pressures. The model is consistent with data for the 14 2018 Kilauea eruption and allows us to estimate for the rst time, the properties of the plumbing 15 system. The results reveal that two reservoirs were active during the eruption and constrain 16 their connectivity. Compared to the model, the Kilauea eruption stopped after producing 17 slightly more than 60% of its potential collapses, possibly due to the presence of the second 18 reservoir. Finally, we show that this physical framework is generally applicable to the largest 19 instrumented caldera collapse eruptions of the past fty years.
DOI: 10.48577/jpl.undrsd
title: Diurnal variability of surface temperature over lakes: Case study for Lake Huron

description: The significance of the diurnal variability of Lake Surface Temperature (LST) has been recog-nized, yet, its magnitude in terms of spatial and temporal variability is not well known. Attempts have been made to derive such information from satellites at high spatial resolution, however most have been made from polar orbiters that sample only twice per day. We describe an effort to derive such information from geostationary satellites at hourly time scale and at about 5-km spa-tial resolution. The approach to derive LST uses the Radiative Transfer for TIROS Operational Vertical Sounder (TOVS) (RTTOV) model driven with the Modern-Era Retrospective analysis for Research and Applications (MERRA)-2 information. The methodology has been implemented over Lake Huron for about six years. We present results of evaluation against various independ-ent satellite products and demonstrate that there is a strong diurnal variability in the skin tem-perature over the lake and that the lowest and highest values as derived twice per day from polar orbiting satellites do not represent appropriately the magnitude of the Diurnal Temperature Range (DTR).
DOI: 10.48577/jpl.8diyxe
title: A Satellite Synthetic Aperture Radar Concept Using P-Band Signals of Opportunity

description: The spaceborne synthetic aperture radar (SAR) technique based on a combination of P-band Signals of Opportunity (SoOp) reflectometry with a sparse array of receivers at low earth orbits (LEO) and transmit signals from the United States Navy’s Mobile User Objective System (MUOS) operating on a geosynchronous altitude has been analyzed. The design focuses on the forward-looking geometry near the specular direction, which allows a high surface reflectivity, in order to obtain adequate signal to noise ratio (SNR) with a moderate receiving antenna gain. The sparse array is utilized to sharpen the across-track resolution and reduce the iso-range ambiguity. The formulation for match-filtering and illustrations of point target response are presented. This work shows that an array of 5 to 7 receivers is able to achieve an across-track resolution of about 200 m in the outer portion of swath and about 1 km in the center part of swath. The along-track resolution can reach 10 meters or better due to the feasibility of a long dwell time for Doppler filtering. We find that the sparse array allows the reduction of the iso-range ambiguity to a level of lower than 5% for a major portion of swath, ~70% or greater depending on the number of receivers and spacing. We have completed an SNR formulation, which can consistently account for both coherent and incoherent scattering regardless the spatial resolution. An analysis of SNR based on the Kirchhoff Approximation for rough surface scattering has been performed. We find that it is possible to obtain a swath width of 100 km with an SNR of 5 dB or better for a constellation of seven satellites with a receiving antenna directivity of 15 dBi at a LEO altitude of 675 km for a wide range of surface roughness. Our study suggests the promise of the SoOpSAR concept for high resolution remote sensing of land surfaces.
DOI: 10.48577/jpl.8vzs1x
title: Using Rescheduling and Flexible Execution to Address Uncertainty in Execution Duration for a Planetary Rover

description: During execution, activity durations may vary from those predicted in the generated schedule. In this article we study (re) scheduling invocation, execution during rescheduling, and flexible execution to enable a high level of responsiveness to uncertainty in activity execution duration. We discuss these methods theoretically in the context of an embedded scheduler and practically in the context of a limited CPU embedded scheduler with a nonzero scheduler runtime intended for a planetary rover. We use the concept of a commit window to enable execution of the previously generated schedule while (re) scheduling. We define \textit{Fixed Cadence} and \textit{Event Driven} scheduling as methods to decide when to reinvoke the scheduler. We define and analyze \textit{Flexible Execution (FE)} as an approach to execute the generated schedule while adapting it to variations in execution. Specifically, FE focuses on (1) how to take advantage of activities ending earlier than expected and (2) how to maintain a consistent schedule if activities take more time than expected. We present a theoretical model and empirical results documenting how these various methods interact and perform on both synthetic data and best available data for NASA's next planetary rover, the Mars 2020 rover. We then describe how these analyses influenced the onboard software for the Mars 2020 rover.
DOI: 10.48577/jpl.clnb6y
title: A Recipe for Geophysical Exploration of Enceladus

description: Orbital geophysical investigations of Enceladus are critical to understanding its energy balance. We identified key science questions for the geophysical exploration of Enceladus, answering which would support future assessment of Enceladus' astrobiological potential. Using a Bayesian framework, we explored how science requirements map to measurement requirements. We performed mission simulations to study the sensitivity of a single spacecraft and dual spacecraft congurations to static gravity and tidal Love numbers of Enceladus. We nd that mapping Enceladus' gravity eld, improving the Corresponding author: Anton Ermakov accuracy of the physical libration amplitude, and measuring Enceladus' tidal response would provide critical constraints on the internal structure, and establish a framework for assessing Enceladus' long term habitability. This kind of investigation could be carried out as part of a life search mission at little additional resource requirements.
DOI: 10.48577/jpl.miewey
title: Calibration of the SHERLOC deep UV fluorescence/Raman spectrometer on the Perseverance Rover

description: We describe the wavelength calibration of the spectrometer for the Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument onboard NASA’s Perseverance Rover. SHERLOC utilizes deep-UV Raman and fluorescence (DUV R/F) spectroscopy to enable analysis of samples on the martian surface. SHERLOC employs a 248.6 nm deep UV laser to generate Raman scattered photons and native fluorescence emission photons from near-surface material to detect and classify chemical and mineralogical compositions. The collected photons are focused on a charge-coupled device (CCD) and the data are returned to Earth for analysis. The compact DUV R/F spectrometer has a spectral range from 249.9 nm to 355.4 nm (~200 cm-1 to 12000 cm-1) (with a spectral resolution of 0.296 nm (∼40 cm−1)). The compact spectrometer uses an off-nominal design to project a high-resolution Raman spectrum and a low-resolution fluorescence spectrum on a single CCD without the need for mechanized components. The natural spectral separation enabled by deep UV excitation enables wavelength separation of the Raman/fluorescence spectra. The SHERLOC spectrometer design optimized the Raman spectral region for resolution, while the fluorescence region was optimized for wavelength range. The resulting illumination on the CCD is curved, requiring a non-traditional, segmented, non-linear wavelength calibration in order to understand the mineralogy and chemistry of martian materials.
DOI: 10.48577/jpl.9uztuk
title: Probabilistic Temporal Networks with Ordinary Distributions: Theory, Robustness and Expected Utility

description: Most existing works in Probabilistic Simple Temporal Networks (PSTNs) base their frameworks on well-defined, parametric probability distributions. Under the operational contexts of both strong and dynamic control, this paper addresses robustness measure of PSTNs, i.e. the execution success probability, where the probability distributions of the contingent durations are ordinary, not necessarily parametric, nor symmetric (e.g. histograms, PERT). In this new realm of PSTNs, we study and formally define concepts such as degree of weak/strong/dynamic controllability, robustness under a predefined dispatching protocol, and introduce the concept of PSTN expected execution utility.We also discuss the limitation of existing controllability levels, and propose new levels within dynamic controllability, to better characterize dynamic controllable PSTNs based on based practical complexity considerations. We propose a novel fixed-parameter pseudo-polynomial time computation method to obtain both the success probability and expected utility measures.We apply our computation method to various PSTN datasets, including realistic planetary exploration scenarios in the context of the Mars 2020 rover. Moreover, we propose additional original applications of the method.
DOI: 10.48577/jpl.u29tx4
title: Introducing the MISR Level 2 Near Real-Time Aerosol Product

description: Atmospheric aerosols are an important element of Earth’s climate system, and have significant impacts on the environment and on human health. Global aerosol modeling has been increasingly used for operational forecasting and as support to decision making. For example, aerosol analyses and forecasts are routinely used to provide air quality information and alerts in both civilian and military applications. The growing demand for operational aerosol forecasting calls for additional observational data that can be assimilated into models to improve model accuracy and predictive skill. These factors have motivated the development, testing, and release of a new near real-time (NRT) level 2 (L2) aerosol product from the Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA’s Terra platform. The NRT product capitalizes on the unique attributes of the MISR aerosol retrieval approach and product contents, such as reliable aerosol optical depth as well as aerosol microphysical information. Several modifications are described that allow for rapid product generation within a three-hour window following acquisition of the satellite observations. Implications for the product quality and consistency are discussed as compared to the current operational L2 MISR aerosol product. Several ways of implementing additional use-specific retrieval screenings are also highlighted.
DOI: 10.48577/jpl.utkojs
title: Triton: Fascinating Moon, Likely Ocean World, Compelling Destination!

description: Triton is an important signpost in understanding the diverse populations of both Ocean Worlds and Kuiper Belt Objects. As a likely ocean world, it is unique by virtue of its kidnapped history from the Kuiper Belt: its large orbital inclination makes it the only ocean world thought to be primarily heated by obliquity tides (Nimmo and Spencer, 2015). It is volatile-rich due to its formation in the outer solar system and its unusual surface geology may be the product of cryovolcanism. Observations from New Horizons and Cassini motivate re-examination of Triton datasets and models, with value for comparative planetology of ocean worlds and KBOs, most notably with Europa, Enceladus, Titan, and Pluto. We re-explore old datasets with the new perspective of the importance of ocean worlds in our solar system and the search for life.
DOI: 10.48577/jpl.amfpy1
title: Using Drifter Velocity Measurements to Assess and Constrain Coarse-Resolution Ocean Models

description: Properly fitting ocean models to observations is crucial for improving modelperformance and understanding ocean dynamics. Near-surface velocity measurementsfrom the Global Drifter Program (GDP) contain valuable information about upper oceancirculation and air-sea fluxes on various space and time scales. This study exploreswhether GDP measurements can be used for usefully constraining the surfacecirculation from coarse-resolution ocean models, using global solutions produced bythe consortium for Estimating the Circulation and Climate of the Ocean (ECCO) as anexample. To address this problem, a careful examination of velocity data errors isrequired. Comparisons between an ECCO model simulation, performed without anydata constraints, and GDP and Ocean Surface Current Analyses Real-time (OSCAR)velocity data, over the period 1992--2017, reveal considerable differences inmagnitude and pattern. These comparisons are used to estimate GDP data errors inthe context of the time-mean and time-variable surface circulations. Both instrumentalerrors and errors associated with limitations in model physics and resolution(representation errors) are considered. Given the estimated model-data differences,errors and signal-to-noise ratios, our results indicate that constraining ocean stateestimates to GDP can have a substantial impact on the ECCO large-scale time-meansurface circulation over extensive areas. Impact of GDP data constraints on the ECCOtime-variable circulation would be weaker and mainly limited to low latitudes.Representation errors contribute substantially to degrading the data impacts.