cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.48577/jpl.bpurcs
title: Estimation and Validation of Sub-Pixel Needleleaf Cover Fraction in the Boreal Forest of Alaska to Aid Fire Management

description: Abstract: Wildfires are a natural part of the boreal ecosystem in Alaska. However, in recent years, Alaska is experiencing frequent and large fires. Environmental conditions (high tempera-ture, low precipitation, and high lightning events) are becoming favorable for severe fire events. Fire releases greenhouse gasses like carbon dioxide into the environment, creating a positive feedback loop for the environment. Needleleaf species are the dominant vegetation in boreal Alaska and are highly flammable. They burn much faster due to the presence of resin, and their low-lying canopy structure promotes fire to spread from the ground to the canopy. Knowing the needleleaf vegetation distribution is crucial for better forest and wildfire management practices. Our study focuses on needleleaf fraction mapping using a well-documented spectral unmixing approach: Multiple Endmember Spectral Mixture Analysis (MESMA). We used an AVIRIS-NG image (5m), upscaled it to 10m and 30m spatial resolutions, and applied MESMA on all three images to assess the impact of spatial resolution on sub-pixel needleleaf fraction estimates. We tested a novel method to validate fraction maps using field data and high-resolution classified hyperspectral image. Our validation method produced needleleaf cover fraction estimates with accuracies of 73%, 79%, and 78% for 5 m, 10m, and 30 m spatial resolution image data, respec-tively. To determine whether these accuracies varied significantly across different spatial scales, we used McNemer statististcal test and found no significant differences between the accuracies. The findings of this study are useful in wildfire management and for understanding changes in forest demography in the boreal region of Alaska.
DOI: 10.48577/jpl.4nzuf8
title: Unfolding the neutron flux spectrum at the surface of Mars using the MSL-RAD and Odyssey-HEND data

description: Understanding the long-term radiation environment at the surface of Mars allows us to estimate the exposure to future robotic and crewed missions. Typically, the radiation environment includes charged particles (i.e., protons and heavier ions) and neutral particles (i.e., gamma rays and secondary neutrons). Previous studies used in-situ measurements, models, or both, to determine the characteristics of the radiation at Mars. For example, the Mars Science Laboratory instrument RAD, or Radiation Assessment Detector, has provided invaluable in-situ data since landing in 2012. However, the RAD instrument is only sensitive to neutrons with energies &gt; ~6 MeV, and therefore misses what is expected to be a substantial flux of lower-energy neutrons. To address this gap, we have developed an approach to derive the surface neutron spectrum using the MSL RAD data augmented by the orbital data from High Energy Neutron Detector onboard Odyssey (neutron energy &lt; ~10MeV). By using the power law fit we were able to find the neutron flux that can reproduce the measurements recorded by RAD and HEND. Our approach involves a series of Monte Carlo particle simulations to develop a set of atmospheric transmission functions, which enables us to convert the on-orbit HEND data to its corresponding surface neutron flux. The combined RAD - HEND data presents a unique opportunity to obtain a complete picture of the surface neutron environment.
DOI: 10.48577/jpl.zzarga
title: Kilometer-Scale Parabolic Reflector for a Radio Telescope in a Lunar Crater

description: We present a structural architecture, as well as packaging and deployment strategies for a parabolic reflector for a conceptual radio telescope on the Moon. We study point designs with the reflector diameter between 350 meters and 1 kilometer. The structural architecture is based on the tension truss concept: a network of tensioned cables with pre-determined length to provide shape and stability, with a compliant metallic mesh stretched between the cables for radio reflectivity. The reflector hangs from the rim of the crater, and the cables are tensioned through self-weight. This method leads to a lightweight design. We present two methods for packaging the reflector. The deployment is envisioned to be carried out by robotic means.
DOI: 10.48577/jpl.e7b8hz
title: High Current Hollow Cathodes for High Power Electric Thrusters

description: Abstract: Higher power Hall thrusters continue to be developed for deep space robotic and human/cargo missions that require higher thrust and specific impulse than available in current thrusters. As the power increases, so does the need for higher current hollow cathode electron sources to drive them. The present generation of Hall thrusters in the 4.5 to 12.5 kW range require hollow cathodes capable of less than 30 A of discharge current with lifetimes of the order of 20 kh. The hollow cathodes intended for the next generation high power thrusters must reliably provide hundreds of amperes of discharge current with high reliability and longer life. NASA successfully demonstrated the XR-100 nested Hall thruster at power levels up to 100 kW, which was driven by a JPL lanthanum hexaboride (LaB6) hollow cathode called the “X3 cathode” operating at 250 A of discharge current. This hollow cathode is the third in a series of JPL LaB6 cathodes that first produced up to 40 A for the H6 thruster, up to 100 A for 20 kW Hall thrusters, and finally this state-of-the-art “X3 cathode” that has been operated at discharge currents of 25-350A in the JPL cathode test facility. The fourth generation of this LaB6 hollow cathode technology has been built and tested at JPL at up to 500 A of discharge current. Extending the discharge current capability to this level presented many challenges. The hollow cathode configuration required to obtain these high discharge currents is described with discussions about thermionic insert design, cathode design to provide sufficient plasma penetration into the insert region to avoid space charge limitations on the thermionic emission, near cathode plume gas injection techniques, heater and thermal considerations, and cathode life.
DOI: 10.48577/jpl.uhphz8
title: 13,000 h Wear Test of a Heaterless Low-Current Lanthanum Hexaboride Hollow Cathode

description: As part of the flight qualification of the Hall thruster component of the Ascendant Sub-kW Transcelestial Electric Propulsion System (ASTRAEUS), the thruster’s proto-flight compact heaterless lanthanum hexaboride hollow cathode was subjected to a long-duration wear test. The cathode was mounted in an ASTRAEUS Hall thruster simulator for the test, which provided a flight-like mechanical, thermal, and magnetic environment for the cathode. The ASTRAEUS cathode was successfully operated for 13,011 h at a discharge current of 4 A using xenon propellant, with a total of 1653 ignitions performed throughout the test. The cathode’s discharge voltage and keeper floating potential were 23.3 V ± 1 V and 3.9 V ± 1 V, respectively, during nominal operation of the device, indicating stable operation that did not change or degrade over the entire duration of the test. Cathode characterizations performed periodically throughout the test, where the cathode was operated at different conditions from the nominal 4 A discharge current, showed that the cathode performance was virtually invariant with operation time. The test was voluntarily terminated due to programmatic constraints. An intermittent keeper-to-cathode short was observed during the test, which was traced to an issue with the weld schedule of the cathode’s internal heat shield that allowed slight contact to occasionally develop. The intermittent short was able to be cleared using the existing capabilities of the ASTRAEUS power processing unit, did not prevent ignition of the cathode, and showed no detrimental effects to cathode performance during steady state operation. This test marks the world’s first 10,000+ h flight qualification test of a compact heaterless lanthanum hexaboride hollow cathode to be used with a low-power magnetically shielded Hall thruster.
DOI: 10.48577/jpl.p7tej2
title: Temporal Multimodal Multivariate Learning

description: Unobserved heterogeneity and randomness of the data have shown multiple modes in probability distribution in each location in a geographic region. A huge collection of multiple sources of granular microscopic data in each location may result in the loss of multivariate information if not retrieved properly. It is important to quantify the uncertainty of prior belief and update posterior when critical observations are obtained. However, traditional entropy theory cannot handle i) sequential learning multimodal multivariate information; ii) dynamic spatiotemporal correlation; iii) importance of observation for posterior approximation. In this paper, we develop a Spatiotemporal Information-retrieval through a Multi-variate Multi-modal Learning (SIMi) framework to address the above challenges by analyzing the similarities between the different types of mixture distributions of multiple variables in each cell and allocating a cluster to each cell across high dimensional time and space. Specifically, SIMi can track structural information flow of temporal multi-variate multi-modal correlation data and automatically update the posterior, with the weights to the new observations through an iterative process. Extensive experiments on real-world datasets, i.e., hurricane ensemble forecasting data and urban traffic data, demonstrate the superior performance of our SIMi method over the state-of-the-art baselines across various settings.
DOI: 10.48577/jpl.zupvuv
title: Delta-Vs and Design Reference Mission Scenarios for Mars Missions

description: Before setting out on any long journey, it is important to first have an idea about how to get there, how long it might take, and how much it will cost. Primarily, the answers depend upon where you are starting and where you wish to go. In the formulative stages of any mission to Mars, having quick estimates of answers to these basic questions will aid in the efficient exploration of the trade space. In this paper, we present a “mileage chart” of sorts illustrating the range of ΔV’s and times-of-flight (TOF) between various starting and stopping points between Earth and Mars. This paper expands upon a chart from a previous work by the authors. We discuss the methodologies used to calculate or estimate expected values and reasonable ranges, including some more detailed specific examples.
DOI: 10.48577/jpl.ta05gp
title: Global Sentinel-1 InSAR Coherence: Opportunities for model-based estimation of land parameters

description: No abstract available.
DOI: 10.48577/jpl.psnikx
title: RETRIEVAL OF DYNAMIC CHANGES OF SURFACE WATER EXTENT FROM SPARSE GNSS-R MEASUREMENTS USING A MODEL-DRIVEN APPROACH

description: While CYGNSS exhibits a high revisit rate, the sparse, quasirandom tracks make it challenging to utilize data at short timescales for inundation mapping. In order to make use of the high revisit rate of CYGNSS, we implement a modeldriven approach in which we compare simulated CYGNSS measurements over a binary water mask with actual CYGNSS measurements. We consider a simple water body like a reservoir that has limited or no vegetation and exhibits dynamic changes in surface water extent within the CYGNSS mission timeframe. We find that our method has the potential to reliably detect changes in surface water extent down to 4 sq. km., corresponding to a 3% increase. Using simple, non-physics-based flood model outputs as inputs to the Endto- End Simulator (E2ES) can lead to the ability to estimate surface water extent over a given area using sparse CYGNSS measurements on sub-weekly timescales.
DOI: 10.48577/jpl.d9ciy8
title: Accuracy of using metastable state measurements in laser-induced fluorescence diagnostics of xenon ion velocity in Hall thrusters

description: Laser-induced fluorescence (LIF) measurements of singly-charged xenon ion velocities in Hall thrusters typically target metastable states due to lack of available laser technology for exciting the ground state. The measured velocity distribution of these metastable ions are assumed to reflect the ground state ion behavior. However, this assumption has not been experimentally verified. To investigate the accuracy of this assumption, a recently developed xenon ion (Xe II) collisional-radiative (CR) model is combined with a 1D fluid model for ions, using plasma parameters from higher fidelity simulations of each thruster, to calculate the metastable and ground state ion velocities as a function of position along the channel centerline. For the HERMeS and SPT-100 thruster channel centerlines, differences up to 0.2 km/s were observed between the metastable and ground state ion velocities. The differences between the metastable ion velocity and ground state ion velocity can be explained by excitations from the slower ground state neutral atoms. While both the ground state ions and metastable state ions experience the same acceleration by the electric field, these small velocity differences arise because ionization directly into these states from the slower neutral ground state can reduce their mean velocities by different amounts. Therefore, the velocity discrepancy may be larger for thrusters with lower propellant utilization efficiency and higher neutral density. For example, differences up to 1.5 km/s were calculated on the HET-P70 thruster channel centerline. Note that although the creation of slow ions can influence the mean velocity, the most probable velocity should be unaffected by these processes.
DOI: 10.48577/jpl.u53qtk
title: Preparation for Launch of the Psyche Spacecraft for NASA's Discovery Program

description: Psyche: Journey to a Metal World, a flight project led by principal investigator Dr. Linda Elkins-Tanton of Arizona State University, was authorized by NASA in February 2021 to enter its system assembly, integration and test phase in preparation for launch in 2022. The Psyche mission is the 14th mission in NASA’s Discovery program. It is enabled by solar electric propulsion and will use SPT-140 Hall thrusters to rendezvous and orbit the largest metal-rich asteroid in the solar system. The spacecraft requires no chemical propulsion and will be the first mission to use Hall thrusters beyond the Earth-Moon system. This paper provides an overview of the project’s progress through its critical design review and system integration and test into preparations for launch operations. It provides overviews of the science objectives, mission concept, and spacecraft design, including design progress made since its preliminary design review, and describes progress made in the environmental test campaign which was conducted on the spacecraft in preparation for shipment to Kennedy Space Center (KSC).
DOI: 10.48577/jpl.lrexnt
title: Lunar Night Survivability of Cryocooled Instruments Using PALETTE Thermally-Switched Enclosures

description: The Planetary and Lunar Environment Thermal Toolbox Elements (PALETTE) project is developing improved thermal management techniques that will allow cryocooled and/or ambient temperature science payloads to survive multiple lunar day/night cycles. The targeted science payloads are those slated to fly on upcoming commercial lunar payload services (CLPS) landers, none of which will likely be able to survive the first lunar night. This paper will provide a status update on those techniques, which include thermally-switched enclosures supported by Vectran tension cables, 3D-printable parabolic reflector radiators (PRRs), “spacerless” MLI whose layers hang from the Vectran cables, advanced thermal isolators using optimized polymeric (and Ti64) designs, and a few others. The paper will include the latest test data from the PALETTE project, which is a three-year effort (initiated in April 2020) funded by the NASA Space Technology Mission Directorate (STMD) Game Changing Development (GCD) program.
DOI: 10.48577/jpl.i4mpgp
title: Technology Demonstration for System of Magnetically Aligning Reconfigurable Tiny Cube Satellites (SMARTCubeS)

description: The development of space-based deployable structures has traditionally been specific to unique mission objectives and constraints, resulting in high financial, temporal, and risk-based costs for single use structures. Recently, literature has considered methods for reducing these barriers by creating small, modular robotic units that can be dynamically reconfigured to adapt to changing mission parameters on-the-fly. Although many existing proposals for such swarms are effective at reshaping their arrangements in real time, they also suffer from drawbacks such as the inability to maintain a power-free holding force. With SMARTCubeS (System of Magnetically Aligned Reconfigurable Tiny Cube Satellites), previous reconfigurable cube satellite swarm designs are improved by introducing several additional functionalities required for realistic operation in an on-orbit environment. Primarily, these advances concern the implementation of a novel method for locking non-powered units together using diametric, cylindrical magnets. By providing these magnets with several degrees of rotational and translational freedom, a series of SMARTCubeS units was developed that passively attract one another in flexible orientations without drawing any additional power to remain locked. Furthermore, a method for actively reconfiguring each cube is implemented using a series of four symmetrically-located electromagnets on the face of each unit. Having properly balanced the forces between the repulsive electromagnets and attracting cylindrical magnets, a system was designed that allows for both transversal and pivoting motion of SMARTCubeS units about their swarm. To demonstrate the feasibility of stepping towards a flight-ready structure, SMARTCubeS were designed using flight-like materials wherever possible. With these advances over existing adaptive space structures, the SMARTCubeS project represents a significant step towards a flight-ready design of reconfigurable space structures such as deployable booms and reflector arrays.
DOI: 10.48577/jpl.pp5t3q
title: Inside Jupiter: what Juno gravity soundings taught us about the gas giant’s interior during the Prime Mission

description: No abstract available.
DOI: 10.48577/jpl.nijnbu
title: Reliability Modeling of Complex Components Using Simulation

description: No abstract available.
DOI: 10.48577/jpl.sv6alg
title: Toward Astrometric Constraints on a Supermassive Black Hole Binary in the Early-Type Galaxy NGC4472

description: No abstract available.
DOI: 10.48577/jpl.e89yrr
title: AAS presentation by APD - CGI photos

description: No abstract available.
DOI: 10.48577/jpl.fasj6b
title: SCHAN: Supercritical CO2 and Subcritical H2O Analysis Instrument for In-Situ Detection of Organics and Life

description: No abstract available.
DOI: 10.48577/jpl.omn0ju
title: Infrared detectors with very high quantum efficiency for sub-Poisson limited interferometry

description: No abstract available.
DOI: 10.48577/jpl.o9rkbu
title: Transport properties of minority carriers in mid-wavelength InAs/InAsSb superlattice infrared detectors

description: No abstract available.
DOI: 10.48577/jpl.hfj1p3
title: Wireless Sub-Nanosecond RF Synchronization for Coherent Multistatic and MIMO Software Defined Radar

description: No abstract available.
DOI: 10.48577/jpl.zurlsq
title: Principles of Time-series SAR Interferometry

description: No abstract available.
DOI: 10.48577/jpl.0ewnnx
title: Towards equilibrium climate states of potential ocean worlds through radiative-convective-photochemical modeling

description: No abstract available.
DOI: 10.48577/jpl.ydhzsq
title: Status of NASA's Starshade Technology Development

description: No abstract available.
DOI: 10.48577/jpl.y3wpcj
title: Wave Perturbation – Global Ionosphere Thermosphere Model (WP-GITM)

description: No abstract available.
DOI: 10.48577/jpl.7xdc5h
title: Is there anyone out there? (talk for kindergarten kids)

description: No abstract available.
DOI: 10.48577/jpl.rzh7jn
title: Dry Heat Sterilization Modeling for Spacecraft Applications

description: No abstract available.
DOI: 10.48577/jpl.9sghby
title: MWIR and LWIR T2SL Focal Plane Arrays for Earth Remote Sensing Applications

description: No abstract available.
DOI: 10.48577/jpl.myzctq
title: SUBSIDENCE IN THE CENTRAL VALLEY AND ITS IMPACT ON THE CALIFORNIA AQUEDUCT

description: No abstract available.
DOI: 10.48577/jpl.h4o9it
title: Lunar Night Survivability of Cryocooled Instruments Using PALETTE Thermally-Switched Enclosures

description: No abstract available.
DOI: 10.48577/jpl.xduqxu
title: A high-flux atom source for atom interferometry

description: No abstract available.
DOI: 10.48577/jpl.yzyvrb
title: PO.DAAC Cloud Data Ecosystem - Part 2: Moving Science to the Cloud

description: No abstract available.
DOI: 10.48577/jpl.pixmyp
title: Floating in a Most Peculiar Way – Cluster Lensing from the Stratosphere with SuperBIT

description: No abstract available.
DOI: 10.48577/jpl.x8udgv
title: MSR Lander Dynamics and Landing Leg Designs with 3/8th Scale Testing

description: No abstract available.
DOI: 10.48577/jpl.zgkfio
title: DEMONSTRATING A NEW FLOOD OBSERVING STRATEGY ON THE NOS TESTBED

description: No abstract available.
DOI: 10.48577/jpl.bcgw9z
title: Automotive Microelectronics in Space Missions

description: No abstract available.
DOI: 10.48577/jpl.4btkyl
title: Watching the Earth Breathe: Space-Based Monitoring of Carbon Dioxide and Solar-Induced Fluorescence with OCO-2 and OCO-3

description: No abstract available.
DOI: 10.48577/jpl.4xsiiw
title: Watching the Earth Breathe: Space-Based Monitoring of Carbon Dioxide and Solar-Induced Fluorescence with OCO-2 and OCO-3

description: No abstract available.
DOI: 10.18112/openneuro.ds004595.v1.0.0
title: EEG: RL Task (3-Armed Bandit) with alcohol cues in hazardous drinkers and ctls
DOI: 10.48577/jpl.wsvubj
title: NASA Technologies for Space Exploration

description: No abstract available.
DOI: 10.26093/cds/vizier.17950161
title: Activity and rotation in Praesepe and the Hyades

description: VizieR online Data Catalogue associated with article published in journal Astronomical Journal (AAS) with title 'The factory and the beehive. II. Activity and rotation in Praesepe and the Hyades.' (bibcode: 2014ApJ...795..161D)
DOI: 10.26093/cds/vizier.18960095
title: X-ray obs. of narrow- and broad-line Seyfert 1 gal.

description: VizieR online Data Catalogue associated with article published in journal Astronomical Journal (AAS) with title 'A comparison of X-ray photon indices among the narrow- and broad-line Seyfert 1 galaxies.' (bibcode: 2020ApJ...896...95O)
DOI: 10.26093/cds/vizier.19030055
title: APOGEE parameters through 83 open clusters

description: VizieR online Data Catalogue associated with article published in journal Astronomical Journal (AAS) with title 'Open Cluster Chemical Homogeneity throughout the Milky Way.' (bibcode: 2020ApJ...903...55P)
DOI: 10.26093/cds/vizier.19040146
title: Young stars in North the America & Pelican Nebulae

description: VizieR online Data Catalogue associated with article published in journal Astronomical Journal (AAS) with title 'The First Extensive Spectroscopic Study of Young Stars in the North America and Pelican Nebulae.' (bibcode: 2020ApJ...904..146F)
DOI: 10.26093/cds/vizier.21920006
title: A GALEX UV imaging survey of nearby galaxies

description: VizieR online Data Catalogue associated with article published in journal Astronomical Journal (AAS) with title 'A GALEX ultraviolet imaging survey of galaxies in the local volume.' (bibcode: 2011ApJS..192....6L)
DOI: 10.26093/cds/vizier.22210007
title: SDSS QSOs at z&lt;0.8. II. New spectroscopic obs.

description: VizieR online Data Catalogue associated with article published in journal Astronomical Journal (AAS) with title 'A large systematic search for close supermassive binary and rapidly recoiling black holes. II. Continued spectroscopic monitoring and optical flux variability.' (bibcode: 2015ApJS..221....7R)