cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.48577/jpl.3mvuzy
title: Missing the reef for the corals: Unexpected trends between coral reef condition and the environment at the ecosystem scale

description: It is incontrovertible that many coral reefs are in various stages of decline and may be unable to withstand the effects of global climate change, jeopardizing vital ecosystem goods and services to hundreds of millions of people around the world. An estimated 50% of the world’s corals have already been lost, and those remaining may be lost by 2030 under the “business as usual” CO2 emissions scenario (Hoegh-Guldberg et al., 2017). However, the foundation of these predictions is a surprisingly sparse dataset, wherein approximately 0.01–0.1% of the world’s reef area has been quantitatively surveyed. Further, the available data comprise observations at the 1–10 m scale, which are not evenly spaced across reefs, but often clustered in areas representing focused survey effort (Edmunds and Bruno, 1996). This impedes modeling and predicting the impact of a changing environment at the ecosystem scale (Pendleton et al., 2016). Here we highlight deficiencies in our current understanding of the relationship between coral reefs and their environments. Specifically, we conduct a meta-analysis using estimates of coral cover from a variety of local surveys, quantitatively relating reef condition to a suite of biogeophysical forcing parameters. We find that readily available public data for coral cover exhibit unexpected trends (e.g., a positive correlation between coral cover and multi-year cumulative thermal stress), contrary to prevailing scientific expectations (Hoegh-Guldberg, 2011). We illustrate a significant gap in our current understanding, and thereby prediction, of coral reefs at the ecosystem scale that can only be remedied with uniform, high-density data across vast coral reef regions, such as that from remote sensing (Mumby et al., 2001; Hochberg, 2011; Hedley et al., 2016a).
DOI: 10.48577/jpl.9x2mkf
title: Merging perspectives on secondary minerals on Mars: A review of ancient water-rock interactions in Gale crater inferred from orbital and in-situ observations

description: Phyllosilicates and sulfates are the most prevalent hydrous minerals detected on Mars from orbit and the surface, including in the Mars Science Laboratory Curiosity rover’s field site at Gale crater. These products of aqueous activity have been investigated in detail in Gale crater, where Curiosity’s X-ray diffractometer allows for direct observation and detailed characterization of mineral structure and abundance. This capability provides critical ground truthing to better understand how to interpret martian mineralogy inferred from orbital datasets. Curiosity is about to leave behind phyllosilicate-rich strata for more sulfate-rich terrains, while the Mars 2020 Perseverance rover is in its early exploration of ancient sedimentary strata in Jezero crater. It is thus an appropriate time to review Gale crater’s mineral distribution from multiple perspectives, utilizing the range of chemical, mineralogical, and spectral measurements provided by orbital and in situ observations. This review compares orbital predictions of composition in Gale crater with higher fidelity (but more spatially restricted) in situ measurements by Curiosity, and we synthesize how this information contributes to our understanding of water-rock interaction in Gale crater. In the context of combining these disparate spatial scales, we also discuss implications for the larger understanding of martian surface evolution and the need for a wide range of data types and scales to properly reconstruct ancient geologic processes using remote methods.
DOI: 10.48577/jpl.7wmrpi
title: The Scientific Importance of Returning Airfall Dust as a Part of Mars Sample Return (MSR)

description: Dust transported in the martian atmosphere is of intrinsic scientific interest as well as having relevance for the planning of human missions in the future. The MSR Campaign, as presently designed, presents an important opportunity to return serendipitous, airfall dust. The tubes containing samples collected by the Perseverance rover would be placed in cache depots on the martian surface perhaps as early as 2023-24 for recovery by a subsequent mission no earlier than 2028-29, and possibly as late as 2030-31. Thus, the sample tube surfaces could passively collect dust for multiple years. This dust is deemed to be exceptionally valuable as it would inform our knowledge and understanding of Mars’s global mineralogy, surface processes, surface-atmosphere interactions, and atmospheric circulation. Preliminary calculations suggest that the total mass of such dust on a full set of tubes could be as much as 100 mg and, therefore, sufficient for many types of laboratory analyses. Two planning steps would optimize our ability to take advantage of this opportunity: 1) the dust-covered sample tubes should be loaded into the Orbiting Sample container (OS) with minimal cleaning, and 2) the capability to recover this dust early in the workflow within the SRF needs to be established. A further opportunity to advance dust/atmospheric science using MSR, depending upon the design of the MSR Campaign elements, may lie with direct sampling and the return of airborne dust.
DOI: 10.48577/jpl.9qfxqy
title: ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions - VI. Hierarchical fragmentation and gas dynamics in IRDC G034.43+00.24

description: We present new observations of 3mm continuum and molecular lines from the ATOMS survey towards two massive protostellar clumps, MM1 and MM2, located in the filamentary infrared dark cloud (IRDC), G034.43+00.24 (G34). The lines observedare the tracers of either dense gas (e.g., HCO+/H13CO+ J=1–0) or outflows (e.g., CS J=2–1). The most complete picture to date of seven cores in MM1 is revealed by dust continuum emission, whereas only two cores are identified in MM2 due to the incomplete coverage of the IRDC in the ATOMS survey. These cores are found to be gravitationally bound, with virial parameter, vir &lt; 2. At least four outflows are identified in MM1 with a total outflowing mass of 45M, and a total energyof 1 1047 ergs, typical of outflows from a B0-type star. Evidence of hierarchical fragmentation, where turbulence dominates over thermal pressure, is observed at both the cloud and the clump scales. This could be linked to the scale-dependent, dynamical mass inflow/accretion on clump and core scales.We therefore suggest that the G34 cloud could be undergoing a dynamical mass inflow/accretion process linked to the multi-scale fragmentation, which leads to the sequential formation of fragments of the initial cloud, clumps, and ultimately dense cores, the sites of star formation.
DOI: 10.48577/jpl.mcfmaq
title: Specific Heat Capacity Measurements of Selected Meteorites for Planetary Surface Temperature Modeling

description: Specific heat capacity Cp(T) is an intrinsic regolith property controlling planetary surface temperatures along with the albedo, density, and thermal conductivity. Cp(T) depends on material composition and temperature. Generally, modelers assume a fixed specific heat capacity value, or a standard temperature dependence derived from lunar basalts, mainly because of limited composition-specific data at low temperatures relevant to planetary surfaces. In addition, Cp(T) only appears to vary by a small factor across various materials, in contrast with the bulk regolith thermal conductivity, which ranges over ~3-4 orders of magnitude as a function of the regolith physical state (grain size, cementation, sintering etc.). For these reasons, the impact of the basaltic assumption on modeled surface temperature is often considered unimportant although this assumption is not particularly well constrained. In this paper, we present specific heat capacity measurements and parameterizations from ~ 90 to ~ 290 K of 28 meteorites including those possibly originating from Mars, and Vesta, and covering a wide range of planetary surface compositions. Planetary surface temperatures calculated using composition-specific Cp(T) are within ± 2 K of model runs assuming a basaltic composition. This ± 2 K range approaches or exceeds typical instrumental noise or other sources of modeling uncertainties. These results suggest that a basaltic assumption for Cp(T) is generally adequate for the thermal characterization of a wide range of planetary surfaces, but possibly inadequate when looking at leveraging subtle trends to constrain subsurface layering, roughness, or seasonal/diurnal volatile transfer.
DOI: 10.48577/jpl.xrkqxu
title: Inclusion of the recoil shift in Doppler-broadened measurements of CO2 transition frequencies

description: We report an important correction to recently reported 12C16O2 transition frequencies and derived spectroscopic constants. A total of 44 previously reported frequencies corresponding to transitions in the (30012 ← 00001) and (30013 ← 00001) band with uncertainties as low as 200 kHz are modified by including the effect of photon-absorption-induced recoil shifts. This shifting mechanism decreases all the transition frequencies by approximately 1.7 kHz.
DOI: 10.48577/jpl.czrfro
title: The Role of Secondary Species Emission in Vacuum Facility Effects for Electrospray Thrusters

description: The role of secondary particle emission (SPE) in the context of electrospray thruster performance, life, and measure- ment uncertainty is explored through discussions on theory, analytical modelling, and experimental investigations. A review of SPE mechanisms is presented, along with an analysis of onset thresholds contextualized for electrospray propulsion, which indicate that SPE should always be expected when testing electrospray thrusters in vacuum facilities. We present arguments that glow discharges observed in electrospray thrusters are a consequence of secondary particles backstreaming to the emission site. An analytical heat and mass flux model is presented to support the hypothesis that SPE-induced Ohmic dissipation may cause performance limitations in electrospray thrusters. For a typical ionic liquid ion source, the results of our model suggest that 7pA to 5.6nA may cause property variation in the liquid. Apply- ing the model to published testing results on the Air Force Electrospray Thruster Series 2 (AFET-2), backstreaming current that contributes to 0.057−23% of the measured emitter current may cause the 0.86μgs−1 neutral mass flow rate observed when testing the AFET-2 thruster. Experimental results of a voltage biasing experiment demonstrate the thruster-to-facility current coupling caused by SPE, which has a substantial effect on measurement uncertainty. Beam target biasing sweeps show that SPE can be effectively mitigated with an appropriate beam target geometry and biasing scheme. The Electrospray SPE Control-volume Analysis for Resolving Ground Operation of Thrusters (ESCARGOT) model is applied to the presented experimental data to determine secondary particle yield and temperature. For cationic species, we found a yield of γ c = 0.131 ions per incident particle and temperature of T c =30 eV. Anionic species have a yield of γ a = 0.29 ions per incident particle, and temperature of T a =88 eV. Our work concludes with suggestions for mitigating SPE when testing electrospray thrusters in vacuum facilities.
DOI: 10.48577/jpl.txtlhl
title: The Photo-z Infrared Telescope (PIRT) – a space instrument for rapid follow up of high-redshift gamma-ray bursts and electromagnetic counterparts to gravitational wave events

description: The Photo-z InfraRed Telescope (PIRT) is an instrument on the Gamow Explorer, currently proposed for a NASA Astrophysics Medium Explorer. PIRT works in tandem with a companion wide-eld instrument, the Lobster Eye X-ray Telescope (LEXT), that will identify x-ray transients likely to be associated with high redshift gamma-ray bursts (GRBs) or electromagnetic counterparts to gravitational wave (GW) events. After receiving an alert trigger from LEXT, the spacecraft will slew to center the PIRT eld of view on the transient source. PIRT will then begin accumulating data simultaneously in ve bands spanning 0.5 { 2.5 microns over a 10 arc-minute eld of view. Each PIRT eld will contain many hundreds of sources, only one of which is associated with the LEXT transient. PIRT will gather the necessary data in order to identify GRB sources with redshift z &gt; 6, with an expected source localization better than 1 arcsec. A near real-time link to the ground will allow timely follow-up as a target of opportunity for large ground-based telescopes or the James Webb Space Telescope (JWST). PIRT will also allow localization and characterization of GW event counterparts. We discuss the instrument design, the on-board data processing approach, and the expected performance of the system.
DOI: 10.48577/jpl.sfbvtz
title: Gravity investigation of Saturn's inner system with the innovative Ring Skimmer concept

description: We present an in-depth feasibility study of innovative gravity science measurements of Saturn’s inner system, which explores the different regions of the rings, the innermost moons and the planet itself. The study is enabled by the novel Skimmer concept, where the spacecraft grazes repeatedly the rings over multiple passes. Because of the spacecraft’s proximity to the rings, the experiment allows for the determination of their radial density distribution with unprecedented accuracy. These observations are especially important for the B and F rings, whose masses are not well-constrained. During the closest approaches to Saturn, the spacecraft is potentially sensitive to its tidal perturbations measured by the Love number k22, which holds key information about the interior structure of the planet. The orbit geometry also allows for close flybys of icy moons not explored by the Cassini mission from a gravity perspective. Specifically, we focus on the measurements of Mimas’s tidal perturbations, indicative of the presence of a submerged ocean under the icy surface. We perform precise numerical simulations of the gravity experiment and provide an account of the expected accuracies by means of a covariance analysis. The results are based on two trajectories of the Skimmer class which differ by altitude over the rings, visibility from Earth, proximity to Saturn and number of passes. We find that the masses of the outer ring regions are determined to better than 0.10 Mimas masses, while the 3σ uncertainty derived for Mimas’s k2 is 0.02.
DOI: 10.48577/jpl.y7jb2a
title: A Mission to Nature's Telescope for High-Resolution Imaging of an Exoplanet

description: The solar gravitational lens (SGL) provides a factor of $10^{11}$ amplification for viewing distant point sources beyond our solar system. As such, it may be used for resolved imaging of extended sources, such as exoplanets, not possible otherwise. To use the SGL, a spacecraft carrying a modest telescope and a coronagraph (needed to block the solar light) must reach the SGLs focal region, that begins at 547 astronomical units (AU) from the Sun and is oriented outward along the line connecting the distant object and the Sun. No spacecraft has ever reached even a half of that distance; and to do so within a reasonable mission lifetime (e.g., less than 25 years) and affordable cost requires a new type of mission design, using solar sails and microsats ($&lt;100$~kg). The payoff is high -- using the SGL is the only practical way we can ever get a high-resolution, multi-pixel image of an Earth-like exoplanet, one that we identify as potentially habitable. This paper describes a novel mission design starting with a rideshare launch from the Earth, spiraling in toward the Sun, and then flying around it to achieve solar system exit speeds of over $20$ AU/year. A new sailcraft design is used to make possible high area to mass ratio for the sailcraft. The mission design enables other fast solar system missions, starting with a proposed very low cost demonstration mission (TDM) to prove the functionality and operation of the microsat-solar sail design and then, building on the TDM, missions to explore distant regions of the solar system, and those to study Kuiper Belt objects (KBOs) and the recently discovered interstellar objects (ISOs) are also possible.
DOI: 10.48577/jpl.hejiup
title: Navigating Fast Interstellar Object Encounters

description: With the discovery of 1I 'Oumuamua and 2I Borisov, interstellar objects (ISOs) have been thrust into the forefront of planetary science, and the robotic exploration of ISOs is now of significant interest. With current propulsion technology, rendezvous with these objects is likely infeasible, and thus the maximum science return results from a combination of flyby spacecraft and impactor spacecraft, as demonstrated by the Deep Impact encounter with comet Tempel 1. Interstellar objects by nature have hyperbolic orbits and pass through the inner solar system at extreme velocities, which presents several unique challenges to navigation. This paper first establishes the possible encounter space intercepts with ISOs may present. We then evaluate the ability for intercepting spacecraft to navigate to ISOs and autonomously track/impact targets across the possible encounter space, depending on key navigation hardware such as camera and attitude determination system.
DOI: 10.48577/jpl.ptubkg
title: The TESS Mission Target Selection Procedure

description: We describe the target selection procedure by which stars are selected for 2-minute and 20-second observa- tions by TESS. We first list the technical requirements of the TESS instrument and ground systems processing that limit the total number of target slots. We then describe algorithms used by the TESS Payload Operation Center (POC) to merge candidate targets requested by the various TESS mission elements (the Target Selection Working Group, TESS Asteroseismic Science Consortium, and Guest Investigator office). Lastly, we summa- rize the properties of the observed TESS targets over the two-year primary TESS mission. We find that the POC target selection algorithm results in 2.1 to 3.4 times as many observed targets as target slots allocated for each mission element. We also find that the sky distribution of observed targets is different from the sky distributions of candidate targets due to technical constraints that require a relatively even distribution of targets across the TESS fields of view. We caution researchers exploring statistical analyses of TESS planet-host stars that the population of observed targets cannot be characterized by any simple set of criteria applied to the properties of the input Candidate Target Lists.
DOI: 10.48577/jpl.0qqqo2
title: Burst properties of the highly active FRB 20201124A using uGMRT

description: We report the observations and the detection of 48 bursts from FRB 20201124A with the upgraded Giant Metrewave Radio Telescope at 550-750 MHz. These observations simultaneously led to the localization of FRB 20201124A to a SDSS galaxy and led to the first detection of persistent radio emission associated with the galaxy. We report the position of the brightest burst to (J2000) RA: 05h08m03.459s, Dec: +26d03'39.14" and measure a flux of 0.7+/-0.1 mJy at 650 MHz. We use DM=411 pc/cm^3 for dedispersion and find that, for the brightest burst with a fluence of 108 Jy ms, the best DM that maximizes the frequency-averaged burst substructure energy of 410.78+/-0.54 pc/cm^3. We find that the cumulative burst rate function has a shallow power law index of gamma = -1.2 +/-0.2 with a rate of 10 bursts per hour up to 10 Jy ms. We detect all bursts above 10 Jy ms, below which the missed fraction is ~30% up to 3 Jy ms. We find that the burst waiting time is largely well approximated by a Poissonian distribution. A search for short as well as longer timescale periodicities yielded no candidates. The bulk drift rates range between -0.75 and -20 MHz/ms. We report an upper limit to the scattering time of 13.6~ms and measure both a scintillation bandwidth of 0.1-0.2 MHz and a scintillation timescale of 8+/-3 min. The simultaneous localization of FRB 20201124A adds strength to the proof-of-concept method adopted from our earlier work. This could serve as a potential model for all our future localization and follow up of unlocalized repeating FRBs with the GMRT.
DOI: 10.48577/jpl.lafaaw
title: Final Report of the MSR Science Planning Group 2 (MSPG2)

description: The currently envisioned Mars Sample Return (MSR) Campaign is one of the most ambitious planetary exploration undertakings ever attempted. Scientifically selected samples collected by NASA’s Mars 2020 would be returned to the Earth through the joint efforts of NASA and the European Space Agency (ESA). Upon delivery to Earth, the samples would be made available to the international science community to conduct investigations addressing some of the most fundamental questions about the formation and evolution of the solar system, and potentially the origins of life. Beginning with Mars 2020 operations, the MSR Campaign must meet a series of scientific and technical achievements to be successful. While the respective engineering responsibilities to retrieve the samples have been formalized through a Memorandum of Understanding (MOU) between ESA and NASA, the roles and responsibilities of the scientific elements have yet to be fully defined. To aid in the process, ESA and NASA jointly chartered the MSR Science Planning Group 2 (MSPG2). The group’s overarching aims were to build upon previous planning efforts in defining 1) an end-to-end MSR Science Program, highlighting a number of important issues that would influence the development and implementation of this Science Program, and 2) needed functionalities and design requirements for an MSR Sample Receiving Facility (SRF). The challenges for the first samples brought from another planet include not only maintaining and providing samples in pristine condition for study, but also maintaining biological containment until the samples are demonstrated to meet sample safety criteria for distribution outside of biocontainment. To maximize the scientific output of the samples, and to minimize the cost and size of an SRF, as many analyses as possible should be conducted in labs outside of biocontainment, either on sterilized samples or after the samples have been determined to be safe for release.
DOI: 10.48577/jpl.5jzn8u
title: Angular momentum distributions for observed and modeled exoplanetary systems

description: The distribution of angular momentum of planets and their host stars provides important information on the formation and evolution of the planetary system. However, mysteries still remain, partly due to bias and uncertainty of the current observational datasets and partly due to the fact that theoretical models for the formation and evolution of planetary systems are still underdeveloped. In this study, we calculate the spin angular momentum of host stars and the orbital angular momentum of their planets using data from the NASA Exoplanet Archive along with detailed analysis of observation dependent biases and uncertainty ranges. We also analyze the angular momentum of the planetary system as a function of star age to understand their variation in different evolutionary stages. In addition, we use a population of planets from theoretical model simulations to reexamine the observed patterns and compare the simulated population with the observed samples to assess variations and differences. We found the majority of exoplanets discovered thus far do not have the angular momentum distribution similar to that of planets in our Solar System, though this could be due to the observation bias. When filtered by the observational biases, the model simulated angular momentum distributions are comparable to the observed pattern in general. However, the differences between the observation and model simulation in the parameter (angular momentum) space provide more rigorous constraints and insights on the issues that needed future improvement.