Primary Scientific Objective Research Articles

Exploring the dielectric loss of Martian regolith in the frequency domain using Zhurong radar data

Martian regolith is one of the primary science objectives of Mars exploration missions. The Rover Penetrating Radar carried by Zhurong rover allows for high-resolution subsurface imaging and in-situ measurements of Martian regolith dielectric properties, which are crucial to advance our understanding of Martian geology and hydrological evolution. While earlier studies have derived dielectric constants for the shallow subsurface, further characterization of subsurface materials requires the determination of attenuation properties. In this study, we applied the centroid-frequency shift method to explore the attenuation property of the Martian regolith in the frequency domain. Lateral attenuation variation was analyzed in detail by integrating subsurface radargram and navigation terrain images. The results show that, within a depth of ∼4 m, the attenuation of radar signal for Zhurong subsurface material is equal to a loss tangent of 0.0079, with a standard deviation of 0.001. Based on the loss tangent value, dielectric permittivity and ground characterization, we preclude the possibility that the regolith is predominantly igneous materials. The lateral variation of the attenuation property could likely be attributed to changes in the proportion of duricrusts, which are heterogeneously distributed along the rover traverse. Our findings offer valuable information for understanding the Martian regolith and its evolution, serving as a important reference for future Mars sample return missions.

Solar Wind Structures from the Gaussianity of Magnetic Magnitude

The heliosphere is permeated with highly structured solar wind originating from the Sun. One of the primary science objectives of Parker Solar Probe (PSP) is to determine the structures and dynamics of the plasma and magnetic fields at the sources of the solar wind. However, establishing the connection between in situ measurements and structures and dynamics in the solar atmosphere is challenging: most of the magnetic footpoint mapping techniques have significant uncertainties in the source localization of a plasma parcel observed in situ, and the PSP plasma measurements suffer from a limited field of view. Therefore, it lacks a universal tool to self-contextualize the in situ measurements. Here we develop a novel time series visualization method named Gaussianity Scalogram. Utilizing this method, by analyzing the magnetic magnitude data from both PSP and Ulysses, we successfully identify in situ structures that are possible remnants of solar atmospheric and magnetic structures spanning more than 7 orders of magnitude, from years to seconds, including polar and midlatitude coronal holes, as well as structures compatible with supergranulation, “jetlets” and “picoflares.” Furthermore, computer simulations of Alfvénic turbulence successfully reproduce the Gaussianization of magnetic magnitude, supporting the observed distribution. Building upon these discoveries, the Gaussianity Scalogram can help future studies to reveal the fractal-like fine structures in the solar wind time series from both PSP and a decades-old data archive.

The VLF Transmitter, Narrowband Receiver, and Tuner Investigation on the DSX Spacecraft

AbstractArtificially enhancing the pitch angle diffusion of the relativistic electrons trapped in the radiation belts with transmission of very‐low frequency (VLF) electromagnetic waves is the primary science objective of the wave‐particle interaction experiments (WPIx) on the Demonstration Science Experiments (DSX) spacecraft. The pitch angle diffusion occurs due to the interaction of stimulated whistler‐mode waves with these extremely high energy electrons. The primary payload of the DSX spacecraft is a high‐power VLF transmitter paired with a matched tuner, a two‐channel narrowband receiver, and an 81.6 m tip‐to‐tip carbon fiber longeron dipole antenna, collectively known as Transmitter, Narrowband receiver, and Tuner (TNT) instrument. TNT can execute a wide variety of programmable WPIx experiments and provide supporting in situ and remote plasma characterizations. In its main high‐power mode, the whistler stimulation on selected frequencies between 2.5 and 34 kHz is done by applying a high‐voltage signal, up to nominally 5 kV, at each transmit antenna monopole feed. Maximum power is radiated when the antenna‐plasma circuit reactance is tuned out, leading to resonance conditions at the selected frequency. In the radiation belts, the unknown and varying contributions of the ambient plasma to the total reactance have to be determined automatically and tuned out adaptively, steering the overall VLF circuit within the resonance state as DSX orbits the Earth. Auxiliary to the main WPIx mode, the low‐power relaxation sounding, remote plasma sensing, and listen‐only VLF‐HF emission spectrographic operations are used to probe the surrounding and remote plasma density and the local magnetic field strength.

Unification of a Global Height System at the Centimeter-Level Using Precise Clock Frequency Signal Links

The International Association of Geodesy (IAG) aims to establish the International Height Reference System (IHRS) as one of its primary scientific objectives. Central to the realization of the IHRS is global vertical datum unification, which requires the connection of existing local vertical height reference systems (VHS) robustly and consistently. However, conventional methods are not suitable for estimating the offsets between two distant local height systems. In this paper, we propose a framework for connecting two local VHSs using ultraprecise clock frequency signal links between satellites and ground stations, referred to as the satellite frequency signal transmission (SFST) approach. The SFST approach allows for the direct determination of the geopotential and height differences between two ground datum stations without any location restrictions between the two VHSs. The simulation results show that the VHSs of China and the US can be unified with an accuracy of several centimeters, provided that the stability of atomic clocks used on-board the satellite and at on-ground datum locations reaches 4.8×10−17τ−1/2 for an averaging time τ (in seconds). We conclude that the SFST approach shows promise for achieving centimeter-level accuracy in unifying the global vertical height datum and represents a new paradigm for the realization of the IHRS.

Intervention-related self-defence

Abstract The scholarly and research-focused article examines the content of Article 25 §§ 4 and 5 CC, which was transferred to the new Article 231b §§ 1 and 2 CC of Chapter XXIX of the Criminal Code by means of Act of 20 February 2015 amending the Criminal Code Act and Certain Other Acts. The regulation concerns the intervention-related self-defence, wherein a person acting in self-defence and repelling an attack on another’s good protected by law, while simultaneously protecting public security or order, is granted the same legal protection as public officials. The article analyses the genesis and development of this defence, its legal nature, objectives, conditions for application, the scope of criminal law protection for a person acting within the intervention-related self-defence, the exclusion of this protection, and the relationship between Article 231b § 1 and Article 217a CC. The primary scientific objective is to evaluate the legitimacy of its introduction to the Criminal Code and the correctness of defining the premises for its application and its scope. The aim of the considerations is to demonstrate that this measure, despite the negative assessment of its introduction to the Criminal Code in the doctrine, can play a vital role in ensuring security and public order.

Antennas for low-frequency radio telescope of SKA

The low-frequency radio telescope of the Square Kilometre Array (SKA) is being built by the international radio astronomical community to (i) have orders of magnitude higher sensitivity and (ii) be able to map the sky several hundred times faster, than any other existing facilities over the frequency range of 50–350 MHz. The sensitivity of a radio telescope array is in general, dependent upon the number of electromagnetic sensors used to receive the sky signal. The total number of them is further constrained by the effects of mutual coupling between the sensor elements, allowable grating lobes in their radiation patterns, etc. The operating frequency band is governed by the desired spatial and spectral responses, acceptable sidelobe and backlobe levels, radiation efficiency, polarization purity and calibratability of sensors’ response. This paper presents a brief review of several broadband antennas considered as potential candidates by various engineering groups across the globe, for the low-frequency radio telescope of SKA covering the frequency range of 50–350 MHz, on the basis of their suitability for conducting primary scientific objectives.

Development of superconducting microcalorimeters for the HUBS mission

Hot Universe Baryon Surveyor (HUBS) is a proposed space-borne observatory for X-ray astronomy. The primary scientific objectives of the mission are to fill a void in probing the ecosystem of galaxies and thus to advance our understanding of galaxy formation and evolution, which is of fundamental importance in cosmology. More specifically, HUBS aims at directly detecting soft X-ray emission from diffuse gas of temperature exceeding 10 6 K, which is theoretically postulated to permeate the large structures in the cosmic web and also fill the extended halo of galaxies. However, although some indirect evidence exists, the presence of such hot gas has yet to be well established observationally, due to the lack of effective tools to probe it. In this paper, we describe the design of HUBS, focusing on its scientific payload, which employs superconducting technologies in the detector system, and particularly on progress in the development of superconducting microcalorimeters.

Probing cosmic inflation with theLiteBIRDcosmic microwave background polarization survey

AbstractLiteBIRD, the Lite (Light) satellite for the study of B-mode polarization and Inflation from cosmic background Radiation Detection, is a space mission for primordial cosmology and fundamental physics. The Japan Aerospace Exploration Agency (JAXA) selected LiteBIRD in May 2019 as a strategic large-class (L-class) mission, with an expected launch in the late 2020s using JAXA’s H3 rocket. LiteBIRD is planned to orbit the Sun–Earth Lagrangian point L2, where it will map the cosmic microwave background polarization over the entire sky for three years, with three telescopes in 15 frequency bands between 34 and 448 GHz, to achieve an unprecedented total sensitivity of $2.2\, \mu$K-arcmin, with a typical angular resolution of 0.5○ at 100 GHz. The primary scientific objective of LiteBIRD is to search for the signal from cosmic inflation, either making a discovery or ruling out well-motivated inflationary models. The measurements of LiteBIRD will also provide us with insight into the quantum nature of gravity and other new physics beyond the standard models of particle physics and cosmology. We provide an overview of the LiteBIRD project, including scientific objectives, mission and system requirements, operation concept, spacecraft and payload module design, expected scientific outcomes, potential design extensions, and synergies with other projects.

Frontier scientific questions in deep space exploration

<p indent="0mm">Deep space exploration is one of the frontiers of scientific research and driven by human instincts to explore the unknown. Since the Moon Race in the 1960s and 1970s, deep-space probes have explored many celestial bodies in our solar system, including eight planets. These explorations have yielded tremendous scientific discoveries, but they also revealed many more unsolved mysteries. The 21st century has witnessed a remarkable increase in deep-space exploration activities, with several new agencies launching their spacecraft in the past few decades. As a result of technological advancement, exploration success rates have improved significantly. A systematic review of frontier scientific questions can provide invaluable references for mission planning strategies and boost scientific discoveries and breakthroughs in the future. In general, these questions are related to three primary scientific subjects: (1) One of the primary scientific objectives of deep-space exploration is to study the origin and evolution of the solar system. From the collapse of the solar nebula to the formation of the planetary system, the solar system has undergone a complex evolutionary process. The components of the current solar system, particularly the residual presolar material, can provide critical information for understanding the initial conditions and evolution of the solar system. The Moon, being the nearest celestial body to Earth, serves as an outpost for exploring other planetary bodies and is especially important for testing deep-space exploration equipment and studying solar system evolution. (2) Another objective of deep space exploration is to better understand the evolution of planetary habitability. The Sun is an important factor affecting habitability, and eruptions of solar activities can have a substantial impact on the space environment of the solar system. The environment of the Earth and other planets has changed dramatically over billions of years of evolution. Although life has only been confirmed on Earth, other celestial bodies might also have had habitable conditions along the evolutionary process. Decoding the evolution of the habitable environment of solar system planetary bodies is of great significance for understanding the formation and evolution of habitable Earth and the origin of life on Earth. (3) Extraterrestrial life detection is a critical scientific topic in deep space exploration, with far-reaching implications for understanding the origin, evolution, and distribution of life in solar and extrasolar systems. The current scientific challenges in the detection of extraterrestrial life primarily involve four aspects: the origin and evolution of life, extraterrestrial habitable environments, life signal identification, and analogy of terrestrial extreme environments. In endeavors to answer these scientific questions, more well-planned deep-space exploration missions are required to collect evidence. In order to outpace opponents in the continuing space exploration endeavor, the National Aeronautics and Space Administration (NASA), the European Space Agency (ESA), and other rising roles have made their ambitious roadmaps. NASA will encourage commercial companies to join future missions through the Artemis program, and has planned missions to explore Venus, asteroids, and icy bodies. The ESA proposed tens of missions in its white paper <italic>Voyage 2050</italic>. In the coming decades, China will lay the groundwork for the International Lunar Research Station through three Chang’e and four Russian Luna missions. Furthermore, Tianwen-2 and Tianwen-3 will return samples from asteroids and Mars, respectively; Tianwen-4 is intended to explore the Jupiter system. The success of these missions will yield unprecedented information for deciphering the mysteries of the solar system and life, as well as considerably expanding our knowledge of the universe we live in.

Landscape of massive black-hole spectroscopy with LISA and the Einstein Telescope

Measuring the quasi-normal mode~(QNM) spectrum emitted by a perturbed black-hole~(BH) --~also known as BH spectroscopy~-- provides an excellent opportunity to test the predictions of general relativity in the strong-gravity regime. We investigate the prospects and precision of BH spectroscopy in massive binary black hole ringdowns, one of the primary science objectives of the future Laser Interferometric Space Antenna~(LISA) mission. We simulate various massive binary BH population models, featuring competing prescriptions for the Delays between galaxy and BH mergers, for the impact of supernova feedback on massive BH growth, and for the initial population of high redshift BH seeds (light versus heavy seeds). For each of these scenarios, we compute the average number of expected events for precision BH spectroscopy using a Fisher-matrix analysis. We find that, for any heavy seed scenario, LISA will measure the dominant mode frequency within ${\cal O}(0.1) \%$ relative uncertainty and will estimate at least 3 independent QNM parameters within $1 \%$ error. The most optimistic heavy seed scenarios produce $\mathcal{O}(100)$ events with $1 \%$ measurability for 3 or more QNM quantities during LISA's operational time. On the other hand, light seed scenarios produce lighter merger remnants, which ring at frequencies higher than LISA's sensitivity. Interestingly, the light seed models give rise to a fraction of mergers in the band of Einstein Telescope, allowing for the measurement of 3 QNM parameters with $\sim 10 \%$ relative errors in approximately a few to ten events/yr. More precise BH spectroscopy in the light seed scenarios would require instruments operating in the deciHertz band.

The CubeSpec space mission

Context. There is currently a niche for providing high-cadence, high resolution, time-series optical spectroscopy from space, which can be filled by using a low-cost cubesat mission. The Belgian-led ESA/KU Leuven CubeSpec mission is specifically designed to provide space-based, low-cost spectroscopy with specific capabilities that can be optimised for a particular science need. Approved as an ESA in-orbit demonstrator, the CubeSpec satellite’s primary science objective will be to focus on obtaining high-cadence, high resolution optical spectroscopic data to facilitate asteroseismology of pulsating massive stars. Aims. In this first paper, we aim to search for pulsating massive stars suitable for the CubeSpec mission, specifically β Cep stars, which typically require time-series spectroscopy to identify the geometry of their pulsation modes. Methods. Based on the science requirements needed to enable asteroseismology of massive stars with the capabilities of CubeSpec’s spectrograph, we combined a literature study for pulsation with the analysis of recent high-cadence time-series photometry from the Transiting Exoplanet Survey Satellite (TESS) mission to classify the variability for stars brighter than V ≤ 4 mag and between O9 and B3 in spectral type. Results. Among the 90 stars that meet our magnitude and spectral type requirements, we identified 23 promising β Cep stars with high-amplitude (non-)radial pulsation modes with frequencies below 7 d−1. Using further constraints on projected rotational velocities, pulsation amplitudes, and the number of pulsation modes, we devised a prioritised target list for the CubeSpec mission according to its science requirements and the potential of the targets for asteroseismology. The full target catalogue further provides a modern TESS-based review of line profile and photometric variability properties among bright O9–B3 stars.

Using Geochemical Fingerprints for Assessing Sediment Source Apportionment in an Agricultural Catchment in Central Argentina

In the hilly semi-arid region of central Argentina, where the agricultural frontier expands at the expense of natural ecosystems, soil erosion is one of the most alarming environmental problems. Thus, obtaining knowledge about the dynamics of erosive processes and identifying erosion hotspots constitutes a primary scientific objective. This investigation is focused on estimating the apportionments of main sources of sediments, at the mouth of a small catchment called Durazno del Medio, located in the province of San Luis, Argentina. Elemental Analysis, measured by Energy Dispersive X-ray Fluorescence (EDXRF), was used to select potential geochemical fingerprints of sediment. The unmixing model MixSIAR was applied to approximate the contribution of each identified source in the sediment accumulation areas at the mouth of the catchment. Potential sediment sources were selected using two criteria: (i) a hierarchical approach to identify the main geomorphological units (GUs) and (ii) the main land uses (LU), recognized by examining satellite images and field recognitions. The selected geochemical tracers were able to distinguish sources located in the Crystalline basement hills with loess-patched (CBH) as the main sediment contributors.

The INSPIRESat-1: Mission, science, and engineering

INSPIRESat-1 (IS-1) is a small scientific satellite being developed jointly by the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado at Boulder in the United States, the Indian Institute of Space Science and Technology (IIST) in India, the National Central University (NCU) in Taiwan and the Nanyang Technological University (NTU) in Singapore. This paper describes the science objectives of the IS-1 mission, the engineering and current development status. The IS-1 has completed all functional and performance tests as well as all environmental tests. The spacecraft is manifested on the Indian Space Research Organization’s (ISRO) Polar Satellite Launch Vehicle (PSLV) C-52 mission in 2021. The IS-1 carries two scientific instruments: the Compact Ionospheric Probe (CIP) developed at NCU for studying Earth’s dynamic ionosphere and the Dual-zone Aperture X-ray Solar Spectrometer (DAXSS) developed at LASP for studying the highly-variable solar X-ray radiation. It also carries a Command and Data Handling board developed by IIST. The primary science objectives of the INSPIRESat-1 are twofold. First, using CIP to characterize the temporal and spatial distributions of small-scale plasma irregularities like plasma bubbles in the ionosphere. Secondly, IS-1 aims to provide a greater understanding of why the Sun’s corona is orders of magnitude hotter than the photosphere, why there is an abundance of elements change during different solar events, and how these events (observed with greater soft x-ray fidelity) affect the earth’s ionosphere. The International Satellite Program in Research and Education (INSPIRE) is a consortium of universities with active space programs, formed to advance space science and engineering.

Sea Surface Salinity and Wind Speed Retrievals Using GNSS-R and L-Band Microwave Radiometry Data from FMPL-2 Onboard the FSSCat Mission

The Federated Satellite System mission (FSSCat), winner of the 2017 Copernicus Masters Competition and the first ESA third-party mission based on CubeSats, aimed to provide coarse-resolution soil moisture estimations and sea ice concentration maps by means of the passive microwave measurements collected by the Flexible Microwave Payload-2 (FMPL-2). The mission was successfully launched on 3 September 2020. In addition to the primary scientific objectives, FMPL-2 data are used in this study to estimate sea surface salinity (SSS), correcting for the sea surface roughness using a wind speed estimate from the L-band microwave radiometer and GNSS-R data themselves. FMPL-2 was executed over the Arctic and Antarctic oceans on a weekly schedule. Different artificial neural network algorithms have been implemented, combining FMPL-2 data with the sea surface temperature, showing a root-mean-square error (RMSE) down to 1.68 m/s in the case of the wind speed (WS) retrieval algorithms, and RMSE down to 0.43 psu for the sea surface salinity algorithm in one single pass.

ICESat-2 and the Trees Around the GLOBE student research campaign: Looking at Earth's tree height, one tree at a time

The NASA Ice, Cloud and land Elevation Satellite-2 or ICESat-2 launched on September 15, 2018 from the Vandenberg Air Force Base aboard the last Delta II rocket. ICESat-2 is designed to map the height of our planet by counting the laser photons leaving and returning to the satellite. Although its primary science objective is to measure the height of Earth's ice, it is able to measure other 3-dimensional objects on Earth, like mountains, buildings, oceans, lakes, trees, etc. The GLOBE Program is an international program of students, educators, scientists, and citizen scientists that allows participants to take measurements in their local environments, in order to see the big picture of how our planet is changing over time. One of the GLOBE measurements is tree height. Students, as part of the Trees Around the GLOBE Student Research Campaign, have been collecting tree height data and comparing it to ICESat-2 tree height data. The Trees Around the GLOBE Student Research Campaign commenced on September 15, 2018 in conjunction with NASA's ICESat-2 satellite launch. This campaign is a student research campaign focusing on tree height. Tree height is not just a measurement, it is a gateway to understanding many things about the environment. The structure of tree canopies and the 3D arrangement of individual trees has a huge effect on how ecosystems function and cycle through carbon, water, and nutrients. As part of the NASA GLOBE Observer Citizen Science Program, a new Trees tool allows citizen scientists to measure tree height using their mobile device. From this, there is an increasingly robust dataset that will allow scientists to use as satellite data comparisons and in potential professional research. Scientists from the ICESat-2 Mission periodically review the tree height data collected by the GLOBE community throughout this campaign and beyond.

ACES/PHARAO: high-performance space-to-ground and ground-to-ground clock comparison for fundamental physics

The Atomic Clock Ensemble in Space is a fundamental physics mission of the European Space Agency to be launched in August 2021. It relies on a high-performance clock onboard the International Space Station (ISS), a network of high-performance clocks on ground, a dedicated 2-way microwave link (MWL) enabling space-to-ground and ground-to-ground clock comparisons, as well as an optical link (ELT). PHARAO/SHM (Projet d’Horloge Atomique par Refroidissement d’Atomes en Orbite/Space Hydrogen Maser), the clock onboard the ISS, has a relative frequency accuracy at the \({10}^{-16}\) level, a relative frequency stability (Allan deviation) equal to \({10}^{-13}/\sqrt{\tau }\) (\(\tau\) being the integration time in seconds) and a time deviation of 12 picoseconds after one day of integration. The MWL is designed to reach a time deviation below 7 ps after one day of integration. While space-to-ground clock comparisons will enable precise tests of the gravitational redshift, tests of deviations from General Relativity at the \({10}^{-6}\) level, and tests of local Lorentz invariance at the \({10}^{-10}\) level, ground-to-ground clock comparisons will enable a search of the time variation of fundamental constants with uncertainty at the \({10}^{-17}\) level after one year. In this contribution, we review the mission setup with a particular emphasis on the MWL, discuss the simulation and data analysis software developed to investigate mission performance, focusing on its primary scientific objective: the test of the gravitational redshift.

Processing GOTO data with the Rubin Observatory LSST Science Pipelines I: Production of coadded frames

Abstract The past few decades have seen the burgeoning of wide-field, high-cadence surveys, the most formidable of which will be the Legacy Survey of Space and Time (LSST) to be conducted by the Vera C. Rubin Observatory. So new is the field of systematic time-domain survey astronomy; however, that major scientific insights will continue to be obtained using smaller, more flexible systems than the LSST. One such example is the Gravitational-wave Optical Transient Observer (GOTO) whose primary science objective is the optical follow-up of gravitational wave events. The amount and rate of data production by GOTO and other wide-area, high-cadence surveys presents a significant challenge to data processing pipelines which need to operate in near-real time to fully exploit the time domain. In this study, we adapt the Rubin Observatory LSST Science Pipelines to process GOTO data, thereby exploring the feasibility of using this ‘off-the-shelf’ pipeline to process data from other wide-area, high-cadence surveys. In this paper, we describe how we use the LSST Science Pipelines to process raw GOTO frames to ultimately produce calibrated coadded images and photometric source catalogues. After comparing the measured astrometry and photometry to those of matched sources from PanSTARRS DR1, we find that measured source positions are typically accurate to subpixel levels, and that measured L-band photometries are accurate to $\sim50$ mmag at $m_L\sim16$ and $\sim200$ mmag at $m_L\sim18$ . These values compare favourably to those obtained using GOTO’s primary, in-house pipeline, gotophoto, in spite of both pipelines having undergone further development and improvement beyond the implementations used in this study. Finally, we release a generic ‘obs package’ that others can build upon, should they wish to use the LSST Science Pipelines to process data from other facilities.

The shape and surface environment of 2016 HO[formula omitted

Asteroid 2016 HO3 is a fast-rotating Near-Earth asteroid (NEA), and a potential target for future exploration. Studying the surface of this asteroid and whether it retains any regolith are primary science objectives, which can provide key clues to the formation and evolution of this small body. In order to support such future explorations, the stability condition for and distribution of regolith on a non-spherical fast-spinning small body are explored in this paper using derived models of 2016 HO3. First, a tri-axial ellipsoid shape model of 2016 HO3 is established based on light curve data. The possible shape configurations are presented. Then, the ambient environment accelerations are analyzed and compared. The stability conditions to retain regolith on the surface of the ellipsoid model is derived and evaluated numerically. The influence of shape, density, cohesion and the angle of friction on the distribution is discussed. Finally, the motion of failed regolith is investigated. The results show that 2016 HO3 is likely an elongated asteroid, which has a length to width ratio smaller than 0.48. A layer of millimeter-sized to centimeter-sized grains can exist on the surface of asteroid 2016 HO3, preferentially kept near the polar and the short axis regions. The required cohesion to bind such particles to the surface is less than 0.2 Pa. Meanwhile, any regolith disturbed from the surface will undergo periods of sliding and bouncing before escaping. This research can provide a reference for preliminary mission design for future missions to asteroid 2016 HO3.

Small Next-Generation Atmospheric Probe (SNAP) Concept to Enable Future Multi-Probe Missions: A Case Study for Uranus

We present the outcome of a mission concept study that designed a small atmospheric entry probe and examined the feasibility and benefit of a future multi-probe mission to Uranus. We call our design the Small Next-generation Atmospheric Probe (SNAP). The primary scientific objective of a multi-probe mission is to reveal spatial variability of atmospheric conditions. This article first highlights that not all measurements must be repeated by multiple probes; some quantities, notably the noble gas abundances and elemental isotopic ratios, are not expected to be variable, and thus need to be performed only by a single large Primary Probe. Our study demonstrates that, by focusing its measurements on spatially variable quantities including atmospheric vapor concentrations, thermal stratification and wind speed, a viable atmospheric probe design is realized with an entry system with 50-cm heatshield diameter and 30-kg atmospheric entry mass. As a case study, we present a detailed analysis of adding SNAP to a notional Uranus Orbiter with Probe mission, which launches in 2031 and arrives at Uranus in 2043, designed by the NASA-funded Science Definition Team study in 2017. We demonstrate that, with minimal changes to the notional carrier mission, a large Primary Probe and SNAP can be delivered to the winter and summer hemispheres to examine seasonal atmospheric variabilities, and transmit data to the Orbiter, which in turn relays the data to Earth. The additional maneuvers needed to deliver SNAP totals a Delta-V of 84 m/s, and consumes 43 kg of propellant. The addition of SNAP is expected to cost $79.5 million in FY2018 dollars; thus, our study demonstrates that a multi-probe mission can be implemented with a 4% cost increase relative to the $2.0 billion cost estimate of the notional mission designed by NASA’s Ice Giant Flagship Science Definition Team study reported in 2017. The SNAP design incorporates several technologies that are currently under development at various Technology Readiness Levels (TRL) between TRL = 4 and TRL = 6. In particular, our study recommends targeted technology development in Thermal Protection System materials, advanced batteries, and miniaturized instruments to enable and enhance future small atmospheric probes like SNAP.

Li-Fraumeni Exploration Consortium Data Coordinating Center: Building an Interactive Web-Based Resource for Collaborative International Cancer Epidemiology Research for a Rare Condition.

The success of multisite collaborative research relies on effective data collection, harmonization, and aggregation strategies. Data Coordination Centers (DCC) serve to facilitate the implementation of these strategies. The utility of a DCC can be particularly relevant for research on rare diseases where collaboration from multiple sites to amass large aggregate datasets is essential. However, approaches to building a DCC have been scarcely documented. The Li-Fraumeni Exploration (LiFE) Consortium's DCC was created using multiple open source packages, including LAM/G Application (Linux, Apache, MySQL, Grails), Extraction-Transformation-Loading (ETL) Pentaho Data Integration Tool, and the Saiku-Mondrian client. This document serves as a resource for building a rare disease DCC for multi-institutional collaborative research. The primary scientific and technological objective to create an online central repository into which data from all participating sites could be deposited, harmonized, aggregated, disseminated, and analyzed was completed. The cohort now include 2,193 participants from six contributing sites, including 1,354 individuals from families with a pathogenic or likely variant in TP53. Data on cancer diagnoses are also available. Challenges and lessons learned are summarized. The methods leveraged mitigate challenges associated with successfully developing a DCC's technical infrastructure, data harmonization efforts, communications, and software development and applications. These methods can serve as a framework in establishing other collaborative research efforts. Data from the consortium will serve as a great resource for collaborative research to improve knowledge on, and the ability to care for, individuals and families with Li-Fraumeni syndrome.