cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.48577/jpl.3avn5w
title: Channelized Thermal Emission, Promethean-type Jets and Surface Changes on Io from Juno Stellar Reference UnitImagery

description: During Juno’s close flybys of Io in 2023 and 2024, its low-light sensitive Stellar Reference Unit (SRU) was used to conduct a high-resolution visible wavelength (450-1,100 nm) imaging campaign under Jupiter-shine illumination. The SRU acquired Juno’s highest resolution image of Io’s surface (895-1230 m/pixel) in December 2023 at a high Jupiter-shine phase angle of ~110 degrees. The image reveals structural changes in Zal Patera since Galileo (1999-2000) and multiple forms of active volcanism within the Zal Montes-Patera complex, including Promethean-type jets at the flow fronts of a new Zal Patera flow branch. The SRU’s sensitivity at redder wavelengths enabled detection of thermal emission from an active lava channel to the west of South Zal Mons. An additional emission signature is seen at the base of a vertical mountain fracture on the western flank of South Zal Mons, suggestive of a tectonically influenced source vent. Indeed, the SRU’s observations in this region suggest a close relationship between mountains and volcanism on Io. The SRU data also provide the first high-resolution view of the geomorphology of the eruptive center Tonatiuh, revealing it to be a compound Promethean-style flow field. SRU imagery from subsequent flybys in February and April 2024 suggest high volcanic activity in the Lei-zi Fluctus region and show increased expansion of the large Masubi flow field in Io’s southern hemisphere.
DOI: 10.48577/jpl.qthp2p
title: A Validation Pipeline for Lunar Digital Elevation Models

description: We present a set of open-source tools developed to verify the accuracy of lunar digital elevation models (DEMs), which are critical for terrain-relative navigation systems used in autonomous extraterrestrial landings. Given the challenges of validating maps without groundbased references, our approach leverages map agreement as a proxy for accuracy. Agreement between DEMs suggests accurate representation of lunar surface features, while disagreement signals potential inaccuracies. We examine key sources of error in lunar DEMs, describe the algorithms used for inter-map comparison, and provide illustrative results from tests conducted on various lunar DEMs. These tools, available at github.com/nasa-jpl/landmark_tools, aim to support future missions by improving confidence in navigation maps.
DOI: 10.48577/jpl.ahyi2p
title: Tight Constraint Prediction of Six-Degree-of-Freedom Transformer-based Powered Descent Guidance

description: This work introduces Transformer-based Successive Convexification (T-SCvx), an extension of Transformer-based Powered Descent Guidance (T-PDG), generalizable for efficient sixdegree-of-freedom (DoF) fuel-optimal powered descent trajectory generation. Our approach significantly enhances the sample efficiency and solution quality for nonconvex-powered descent guidance by employing a rotation invariant transformation of the sampled dataset. T-PDG was previously applied to the 3-DoF minimum fuel powered descent guidance problem, improving solution times by up to an order of magnitude compared to lossless convexification (LCvx). By learning to predict the set of tight or active constraints at the optimal control problem’s solution, Transformer-based Successive Convexification (T-SCvx) creates the minimal reduced-size problem initialized with only the tight constraints, then uses the solution of this reduced problem to warm-start the direct optimization solver. 6-DoF powered descent guidance is known to be challenging to solve quickly and reliably due to the nonlinear and non-convex nature of the problem, the discretization scheme heavily influencing solution validity, and reference trajectory initialization determining algorithm convergence or divergence. Our contributions in this work address these challenges by extending T-PDG to learn the set of tight constraints for the successive convexification (SCvx) formulation of the 6-DoF powered descent guidance problem. In addition to reducing the problem size, feasible and locally optimal reference trajectories are also learned to facilitate convergence from the initial guess. T-SCvx enables onboard computation of real-time guidance trajectories, demonstrated by a 6-DoF Mars powered landing application problem.
DOI: 10.48577/jpl.nbv5ad
title: Assessing the Feasibility of Ion Beam-based Asteroid Deflection for Planatary Defense

description: This work analyzes the feasibility of ion beam-based deflection (IBD) for potentially hazardous asteroids. The key components for ensuring IBD feasiblity are the accurate modeling of the ion-beam and spacecraft dynamics and the development of the hovering controller laws for the IBD spacecraft. The modeling of the ion beam is conducted at three different levels of fidelity, going from point force to a Gaussian distributed beam that better represents the reality. The spacecraft and small body dynamics are modelled to include the effect of gravitational harmonics up to the 8th order, along with pertubations due to solar radiation pressure. Autonomous hovering control algorithms are developed for a spacecraft that performs long-duration ion beam deflection. The relative position of the spacecraft is maintained via a PID controller, while the attitude control utilizes a nonlinear PD controller. Monte-Carlo simulations are conducted on asteroids of varying characteristics, such that the IBD operations can be tested across a range of likely scenarios. Deflection is studied for asteroids of equivalent spherical diameters ranging from 50 m − 150 m and densities from 1 g cm−3 − 8 g cm−3. The effect of asteroid shape on the effectivity of IBD is analyzed by considering irregular small body shapes such as Spherical,Itokawa and 67P and intermediate shapes into account. The impact of asteroid spin axes (best vs worst spin axes alignment) is also considered. The study illustrates that IBD can be feasible strategy of asteroid deflection for the extreme cases considered, provided that sufficient deflection time is available.
DOI: 10.48577/jpl.vnzkig
title: Advances in ocean surface modeling to correct for sun and sky glint contributions in imaging spectroscopy measurements

description: Remote sensing of water bodies is critical for monitoring ecosystems of oceans and lakes. Estimates of chlorophyll concentration or phytoplankton blooms can provide valuable insights into environmental processes and anthropogenic disturbances. Imaging spectroscopy measurements feature the spectral resolution to detect and quantify these constituents. One of the challenging factors impacting the accuracy of these retrievals is surface glint. Glint correction algorithms are commonly applied as a post-hoc method introducing substantial uncertainties. We present a new approach that couples a physics-based surface model with simulations of atmospheric radiative transfer to estimate glint-corrected water-leaving reflectance directly from measured radiance. The model is validated with measurements from the PRISM sensor. We show that magnitude and shape of estimated remote sensing reflectance improves as the contribution of glint is removed. Our findings are essential for the conceptualization of retrieval algorithms for future spaceborne imaging spectroscopy missions, such as SBG and CHIME.
DOI: 10.15468/dl.qmxds8
title: Occurrence Download

description: A dataset containing 3033 species occurrences available in GBIF matching the query:
{
 "and" : [
 "Geometry POLYGON((2.21922 43.15687,2.88745 43.15687,2.88745 43.39071,2.21922 43.39071,2.21922 43.15687))",
 "HasGeospatialIssue is false",
 "OccurrenceStatus is Present",
 "TaxonKey is Amphibia"
 ]
}

 The dataset includes 3033 records from 59 constituent datasets; see https://api.gbif.org/v1/occurrence/download/0065293-241126133413365/datasets/export for details.
 
Data from some individual datasets included in this download may be licensed under less restrictive terms.
DOI: 10.48577/jpl.wblrhd
title: Current Status and Analyses of the SPLICE Hazard Detection Software

description: This paper provides a status report of the current development and analysis efforts for the hazard detection (HD) software for the Safe and Precise Landing-Integrated Capabilities Evolution (SPLICE) project.
DOI: 10.48577/jpl.8frqeh
title: Diffusion Policies for Generative Modeling of Spacecraft Trajectories

description: Machine learning has demonstrated remarkable promise for solving the trajectory generation problem and in paving the way for online use of trajectory optimization for resource-constrained spacecraft. However, a key shortcoming in current machine learning-based methods for trajectory generation is that they require large datasets and even small changes to the original trajectory design requirements necessitate retraining new models to learn the parameter-tosolution mapping. In this work, we leverage compositional diffusion modeling to efficiently adapt out-of-distribution data and problem variations in a few-shot framework for 6 degreeof- freedom (DoF) powered descent trajectory generation. Unlike traditional deep learning methods that can only learn the underlying structure of one specific trajectory optimization problem, diffusion models are a powerful generative modeling framework that represents the solution as a probability density function (PDF) and this allows for the composition of PDFs encompassing a variety of trajectory design specifications and constraints. We demonstrate the capability of compositional diffusion models for inference-time 6 DoF minimum-fuel landing site selection and composable constraint representations. Using these samples as initial guesses for 6 DoF powered descent guidance enables dynamically feasible and computationally efficient trajectory generation.
DOI: 10.48577/jpl.tqjhm3
title: Modeling_the_Deployment_of_a_Flight_Like_Starshade_Inner_Disk_Subsystem

description: This study demonstrates the use of a numerical model to simulate the deployment of a starshade inner disk subsystem (IDS) to predict the random shape repeatability error of a large deployable optical system. Past work has shown that a finite element (FE) model created in the commercial code Abaqus can predict the random shape repeatability error to within 5% compared to 22 deployment tests of a prototype test article, and identified that accurate and computationally efficient models of the friction and gap in the hinges are critical to achieving excellent correlation to test measurements. In the current work, the FE modeling approach was employed to represent a more mature starshade IDS configuration through the addition of a flight-like origami folded optical shield and large, flexible petals mounted to the perimeter truss. Several sets of numerical sensitivity studies identified the critical parameters that strongly affect the random shape repeatability errors and bounded the influence of uncertainty in the assembly process and internal preloads. Random shape repeatability error predictions from 44 dynamic deployment simulations spanning a conservative range of the studied parameters verified that the IDS deployed shape repeatability errors would be well within the requirements. This work has shown that the predictions of numerical models, when complementing physical testing, can play a valuable role in the development of deployable optical systems.
DOI: 10.48577/jpl.1mwbg6
title: Illumination Invariant Image Matching for Lunar TRN

description: A major challenge for vision-based applications of planetary exploration is large illumination variance that is caused by a combination of the sun position, terrain morphology, and lack of light scattering due to the absence of an atmosphere. This diminishes the capability to recognize terrain features or landmarks that are critical for autonomous robotic operations, including spacecraft pinpoint landing, UAV, or UGV navigation. The upcoming Mars Sample Return (MSR) mission exemplifies this challenge, potentially landing in the early morning, in stark contrast to the late afternoon landings of all previous Mars missions. This significant shift in lighting conditions, from the afternoon imagery used to create the reference map to early morning terrain appearance in descent imagery, poses a substantial challenge to existing Terrain Relative Navigation (TRN) algorithms. Consistently recognizing the same features or landmarks under such varied lighting conditions has been a long-standing open problem. In response, this paper introduces two approaches for robust image matching under illumination variation: 1) A new correlation-based algorithm — the Lighting Invariant Matching Algorithm (LIMA), and 2) a novel application of deep learning for learning illumination invariant features. Both approaches are supported by experiments on synthetic and real datasets.
DOI: 10.48577/jpl.chxf6y
title: Autonomous Trajectory Planning for Asteroid Reconnaissance under Uncertainty

description: This paper presents the development and evaluation of an optimization-based autonomous trajectory planning algorithm for the asteroid reconnaissance phase of a deep-space exploration mission. The reconnaissance phase is a low-altitude flyby to collect detailed information around a potential landing site. Although such autonomous deep-space exploration missions have garnered considerable interest recently, state-of-the-practice in trajectory design involves a time-intensive ground-based open-loop process that forward propagates multiple trajectories with a range of initial conditions and parameters to account for uncertainties in spacecraft knowledge and actuation. In this work, we introduce a stochastic trajectory optimization-based approach to generate trajectories that satisfy both the mission and spacecraft safety constraints during the reconnaissance phase of the Deep-space Autonomous Robotic Explorer (DARE) mission concept, which seeks to travel to and explore a near-Earth object autonomously, with minimal ground intervention. We first use the Multi-Spacecraft Concept and Autonomy Tool (MuSCAT) simulation framework to rigorously validate the underlying modeling assumptions for our trajectory planner and then propose a method to transform this stochastic optimal control problem into a deterministic one tailored for use with an off-the-shelf nonlinear solver. Finally, we demonstrate the efficacy of our proposed algorithmic approach through extensive numerical experiments and show that it outperforms the state-of-the-practice benchmark used for representative missions.
DOI: 10.48577/jpl.68soia
title: Development_Effort_for_Precision_Manufacturing_of_Starshade_Petals

description: The Starshade is a precision deployable structure hosting an optical payload that flies in formation with a space-based telescope to enable direct imaging of exoplanets. The Starshade reference design featured in this paper includes a 10-meter inner disk structure that hosts 24 8-meter long petals. The optical payload is a microns-precise profile created by sharp amorphous foil along the entire perimeter of the structure. The substructure that hosts this foil is referred to as the petal, and the perimeter of the petal structure comprises of several optical edge segments. This paper details the precision manufacturing of optical edge segments and a sub-scale petal structure. The optical edge segments are manufactured to meet the ideal shape profile within 25 microns RMS, with a mean of 11 microns RMS for all optical edge units. Four of these optical edges were then installed into the sub-scale Petal structure such that the overall profile width error was 25 microns RMS. This demonstrates that the optical payload components of the Starshade structure can be manufactured successfully with contemporary technology.
DOI: 10.48577/jpl.e1rfzg
title: Shape_Accuracy_Analysis_of_Starshade_Petals

description: A starshade is a large deployable light-blocking screen used in tandem with a telescope for direct imaging of planets around other stars. The overall deployment of a starshade relies heavily on the deployment of its individual petals. The petal is stowed for prolonged periods before deployment. This necessitates thorough assessment of the laminated composite structure used in the petals. Through viscoelastic testing and simulations, it is shown that the shape accuracy of the petals is remarkably influenced by the polymer viscoelasticity. This paper presents the modeling and characterization of the composite laminates, as well as simulations and experiments on the deployed shape of segments of a petal. In-plane and out-of-plane shape distortions are addressed to develop an understanding of the dimensional stability and shape accuracy of the starshade petals.
DOI: 10.48577/jpl.tsjjay
title: Development Effort for Precision Manufacturing of Starshade petals

description: No abstract available.
DOI: 10.48577/jpl.qhck58
title: Progress on Hall2De Simulations with First-Principles Model of the Anomalous Momentum-Transfer Collision Frequency

description: We report on the first set of numerical simulations that make use of a recently developed first principles, closed-form model of the anomalous momentum-transfer collision frequency in a Hall thruster discharge. First, the model is implemented only in the interior of the channel, upstream of the acceleration region, while in the downstream portion an empirically derived model is still applied. We find that these simulations agree well with experimental measurements and can reproduce the dynamic behavior of the plasma. We then report on our first attempts to implement the model everywhere in the computational domain. We were able to achieve a stable simulation in the SPT-140 in which the steady state solution reproduced quite well the measured ion velocity. These first numerical experiments have also confirmed some expected challenges, however, mainly associated with the ab initio prediction of the location of the maximum out-of-plane drift velocity inside the channel. We outline possible avenues for overcoming this challenge, such as augmenting the model with the anomalous electron heating that also occurs in the presence of plasma instabilities.
DOI: 10.48577/jpl.q2jwpq
title: Ground Testing of Spacecraft Attitude Dynamics during In-Space Assembly and Manufacturing

description: The on-orbit construction of structures, i.e., in-space assembly and manufacturing (ISAM), is a promising approach for increasing mission ŕexibility and achieving structures optimized for the space environment. Although many construction processes have been proposed, a critical aspect that needs further investigation is the spacecraft attitude dynamics during ISAM, given the large changes in mass properties of the spacecraft and the long timescales of fabrication. This work investigates the ground testing of spacecraft attitude dynamics during Bend-Forming, a candidate process for the on-orbit construction of truss structures via plastic deformation of metallic feedstock. Speciőcally, we conduct experiments on a planar air bearing platform and develop rigid body dynamics models to understand the platform motion during Bend-Forming. The experimental results reveal 1) the effect of metal springback on the attitude dynamics, and 2) the possibility of control-structure interaction during closed-loop, thruster-based position and attitude control. Overall, this study highlights how artifacts of the manufacturing process like springback affect attitude dynamics and results in important guidelines for the ground testing of spacecraft attitude dynamics during ISAM.
DOI: 10.48577/jpl.0hcsif
title: Current Status and Analyses of the SPLICE Hazard Detection Software

description: No abstract available.
DOI: 10.48577/jpl.xjjcva
title: COMPONENTS, SYSTEMS, and their OPERATING WAVELENGTH:A Peculiar Personal View of the History of Radio Technology, Radio Astronomy, and Quasioptics

description: No abstract available.
DOI: 10.48577/jpl.5iycft
title: TOLIMAN: An Astrometry Mission to Detect Earth Analogs Orbiting the Nearest Sun-like Stars

description: No abstract available.
DOI: 10.48577/jpl.vhmrjn
title: Double Asteroid Redirection Test (DART), Hera, and the latest on Europa Clipper

description: No abstract available.
DOI: 10.48577/jpl.2kn22t
title: Measurement of SPT-140 Hall Thruster Swirl Torque during the Psyche Mission

description: Hall-thruster swirl torque is small enough that it is difficult to measure in ground-based facilities, but large enough that its effects on interplanetary spacecraft can be significant and must be actively managed. NASA’s Psyche mission has provided the first opportunity to directly measure the swirl torque produced by a Hall thruster operating at powers greater than 1.5 kW. When the electric propulsion system is operating, the spacecraft attitude control methodology forces the net torque on the spacecraft to align with a pre-determined direction in the body frame, after which the thruster-induced swirl torque can be separated from the other torques acting on the spacecraft. The swirl torques produced by three of the four thrusters on the Psyche spacecraft were determined over the full operating discharge power range of 1.0 to 4.5 kW, and the maximum value of that torque was 0.86 mN-m at full power. It is shown that the SPT-140 swirl torque results can be scaled from full power to lower powers by the product of the discharge current and the magnet current, and evaluation of cruise thrusting data as the thruster is throttled down in power suggests that swirl torque is not changing significantly with time as a function of operating condition. Finally, calculations of swirl torque using updated numerical simulations are shown to agree reasonably well with the flight data, thus providing confidence in their use for other thrusters prior to flight.
DOI: 10.48577/jpl.zwk8pw
title: Deployable Petal-Type Millimeter-Wave Radio Reflectors for Small Spacecraft

description: We describe a “petal-type” concept for a deployable parabolic reflector that may be stowed on- board a small ESPA-class spacecraft and provide sufficient deployed surface shape repeatability for operation at radio frequencies as high as 175 GHz. While petal-type reflectors have been demonstrated for high radio frequencies at large sizes and such reflectors have been developed for small spacecraft at lower frequencies, this work demonstrates performance sufficient for millimeter-wave radio at size-scales relevant for small spacecraft using deployment repeatability experiments on a full-scale test article.
DOI: 10.48577/jpl.matwcc
title: Velocity-Resolved Fine Structure Line Observations and Star Formation: New Results and New Capabilities

description: No abstract available.
DOI: 10.48577/jpl.ie9j2s
title: EXEP: Starshade Technology Status: Optics

description: No abstract available.
DOI: 10.48577/jpl.bzhs01
title: Planetary Science Missions at JPL

description: No abstract available.