Subjects -> AERONAUTICS AND SPACE FLIGHT (Total: 124 journals)
 Showing 1 - 30 of 30 Journals sorted by number of followers AIAA Journal       (Followers: 1006) SpaceNews       (Followers: 782) Journal of Spacecraft and Rockets       (Followers: 705) Journal of Propulsion and Power       (Followers: 572) Aviation Week       (Followers: 415) Aerospace Science and Technology       (Followers: 309) Advances in Space Research       (Followers: 297) IEEE Transactions on Aerospace and Electronic Systems       (Followers: 284) Journal of Aircraft       (Followers: 267) IEEE Aerospace and Electronic Systems Magazine       (Followers: 254) Control Systems       (Followers: 239) Acta Astronautica       (Followers: 223) Gyroscopy and Navigation       (Followers: 181) Journal of Navigation       (Followers: 180) Journal of Guidance, Control, and Dynamics       (Followers: 168) Aircraft Engineering and Aerospace Technology       (Followers: 142) Space Science International       (Followers: 119) Space Science Reviews       (Followers: 92) Propulsion and Power Research       (Followers: 89) International Journal of Aerospace Engineering       (Followers: 86) Progress in Aerospace Sciences       (Followers: 82) Advances in Aerospace Engineering       (Followers: 74) Journal of Aerospace Engineering       (Followers: 66) Aerospace       (Followers: 64) Journal of Aerospace Information Systems       (Followers: 57) Space Safety Magazine       (Followers: 50) International Journal of Aerodynamics       (Followers: 46) IEEE Transactions on Circuits and Systems I: Regular Papers       (Followers: 43) Space Research Today       (Followers: 43) Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering       (Followers: 42) International Journal of Aeroacoustics       (Followers: 37) International Journal of Aerospace Sciences       (Followers: 36) Canadian Aeronautics and Space Journal       (Followers: 31) Space Policy       (Followers: 30) Journal of Space Weather and Space Climate       (Followers: 30) CEAS Aeronautical Journal       (Followers: 30) Journal of Aerodynamics       (Followers: 27) Journal of Aerospace Information Systems       (Followers: 27) Egyptian Journal of Remote Sensing and Space Science       (Followers: 25) Russian Aeronautics (Iz VUZ)       (Followers: 23) International Journal of Aerospace Innovations       (Followers: 23) Aviation Psychology and Applied Human Factors       (Followers: 23) Aerospace Medicine and Human Performance       (Followers: 22) International Journal of Aerospace Psychology       (Followers: 22) Journal of Aerospace Engineering & Technology       (Followers: 22) Journal of Wind Engineering and Industrial Aerodynamics       (Followers: 21) Artificial Satellites       (Followers: 21) Fatigue of Aircraft Structures       (Followers: 21) Research & Reviews : Journal of Space Science & Technology       (Followers: 20) Frontiers in Aerospace Engineering       (Followers: 20) International Journal of Space Structures       (Followers: 19) Nonlinear Dynamics       (Followers: 19) Chinese Journal of Aeronautics       (Followers: 19) Proceedings of the Human Factors and Ergonomics Society Annual Meeting       (Followers: 16) International Journal of Satellite Communications Policy and Management       (Followers: 15) Frontiers in Astronomy and Space Sciences       (Followers: 15) Journal of Aircraft and Spacecraft Technology       (Followers: 15) Advances in Aerospace Science and Technology       (Followers: 14) International Journal of Space Science and Engineering       (Followers: 13) Aviation       (Followers: 12) International Journal of Micro Air Vehicles       (Followers: 11) Journal of Airline and Airport Management       (Followers: 11) Journal of the Astronautical Sciences       (Followers: 11) International Journal of Space Technology Management and Innovation       (Followers: 11) Population Space and Place       (Followers: 10) Journal of Aviation Technology and Engineering       (Followers: 10) Journal of Aeronautical Materials       (Followers: 10) Aerospace Systems       (Followers: 10) International Journal of Crashworthiness       (Followers: 10) Journal of Aerospace Technology and Management       (Followers: 10) Aeronautical Journal, The       (Followers: 9) Journal of the American Helicopter Society       (Followers: 9) International Journal of Aviation, Aeronautics, and Aerospace       (Followers: 9) International Journal of Aviation Technology, Engineering and Management       (Followers: 8) Journal of Space Safety Engineering       (Followers: 8) International Journal of Applied Geospatial Research       (Followers: 7) Transportmetrica A : Transport Science       (Followers: 7) Aerospace technic and technology       (Followers: 7) Air Medical Journal       (Followers: 7) Aviation in Focus - 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Similar Journals
 Space Science ReviewsJournal Prestige (SJR): 3.262 Citation Impact (citeScore): 7Number of Followers: 92      Hybrid journal (It can contain Open Access articles) ISSN (Print) 1572-9672 - ISSN (Online) 0038-6308 Published by Springer-Verlag  [2469 journals]
• Theory of Cosmic Ray Transport in the Heliosphere

Abstract: Abstract Modelling the transport of cosmic rays (CRs) in the heliosphere represents a global challenge in the field of heliophysics, in that such a study, if it were to be performed from first principles, requires the careful modelling of both large scale heliospheric plasma quantities (such as the global structure of the heliosphere, or the heliospheric magnetic field) and small scale plasma quantities (such as various turbulence-related quantities). Here, recent advances in our understanding of the transport of galactic cosmic rays are reviewed, with an emphasis on new developments pertaining to their transport coefficients, with a special emphasis on novel theoretical and numerical simulation results, as well as the CR transport studies that employ them. Furthermore, brief reviews are given of recent progress in CR focused transport modelling, as well as the modelling of non-diffusive CR transport.
PubDate: 2022-05-25

• The Early History of Heliospheric Science and the Spacecraft That Made It
Possible

Abstract: Abstract Our understanding of the interaction of the large-scale heliosphere with the local interstellar medium (LISM) has undergone a profound change since the very earliest analyses of the problem. In part, the revisions have been a consequence of ever-improving and widening observational results, especially those that identified the entrance of interstellar material and gas into the heliosphere. Accompanying these observations was the identification of the basic underlying physics of how neutral interstellar gas and interstellar charged particles of different energies, up to and including interstellar dust grains, interacted with the temporal flows and electromagnetic fields of the heliosphere. The incorporation of these various basic effects into global models of the interaction, whether focused on neutral interstellar gas and pickup ions, energetic particles such as anomalous and galactic cosmic rays, or magnetic fields and large-scale flows, has profoundly changed our view of how the heliosphere and LISM interact. This article presents a brief history of the conceptual and observation evolution of our understanding of the interaction of the heliosphere with the local interstellar medium, up until approximately 1996.
PubDate: 2022-05-25

• Observations and Modeling of Martian Auroras

Abstract: Abstract Observations of planetary auroras form a new area of planetary exploration from space, especially for nonmagnetic planets since various kinds of auroras like Discrete, Proton and Diffuse auroras have been observed at Mars. We review the latest results of Martian auroras obtained by the instruments (1) SPICAM (Spectroscopy for the Investigation of the Characteristics of the Atmosphere of Mars) aboard Mars Express (MEX) and (2) IUVS (the Imaging Ultraviolet Spectrograph) on MAVEN (the Mars Atmosphere and Volatile Evolution mission). The MARSIS instrument (the Mars Advanced Radar for the Subsurface and Ionosphere Sounding) on MEX, in addition, exhibited strong ionizations in some electron density profiles, thus providing further evidence for the existence of Martian auroras. We review these MARSIS observations as well. In addition, we review various models of Martian auroras.
PubDate: 2022-05-24

• The Heliosphere and Local Interstellar Medium from Neutral Atom
Observations at Energies Below 10 keV

Abstract: Abstract As the heliosphere moves through the surrounding interstellar medium, a fraction of the interstellar neutral helium, hydrogen, and heavier species crossing the heliopause make it to the inner heliosphere as neutral atoms with energies ranging from few eV to several hundred eV. In addition, energetic neutral hydrogen atoms originating from solar wind protons and from pick-up ions are created through charge-exchange with interstellar atoms. This review summarizes all observations of heliospheric energetic neutral atoms and interstellar neutrals at energies below 10 keV. Most of these data were acquired with the Interstellar Boundary Explorer launched in 2008. Among many other IBEX breakthroughs, it provided the first ever all-sky maps of energetic neutral atoms from the heliosphere and enabled the science community to measure in-situ interstellar neutral hydrogen, oxygen, and neon for the first time. These observations have revolutionized and keep challenging our understanding of the heliosphere shaped by the combined forces of the local interstellar flow, the local interstellar magnetic field, and the time-dependent solar wind.
PubDate: 2022-05-23

• Correction to: Determining the Relative Cratering Ages of Regions of
Psyche’s Surface

PubDate: 2022-05-18

• Astrospheres of Planet-Hosting Cool Stars and Beyond ⋅ When Modeling
Meets Observations

Abstract: Abstract Thanks to dedicated long-term missions like Voyager and GOES over the past 50 years, much insight has been gained on the activity of our Sun, the solar wind, its interaction with the interstellar medium, and, thus, about the formation, the evolution, and the structure of the heliosphere. Additionally, with the help of multi-wavelength observations by the Hubble Space Telescope, Kepler, and TESS, we not only were able to detect a variety of extrasolar planets and exomoons but also to study the characteristics of their host stars, and thus became aware that other stars drive bow shocks and astrospheres. Although features like, e.g., stellar winds, could not be measured directly, over the past years several techniques have been developed allowing us to indirectly derive properties like stellar mass-loss rates and stellar wind speeds, information that can be used as direct input to existing astrospheric modeling codes. In this review, the astrospheric modeling efforts of various stars will be presented. Starting with the heliosphere as a benchmark of astrospheric studies, investigating the paleo-heliospheric changes and the Balmer $$\text{H}\upalpha$$ projections to $$1~\text{pc}$$ , we investigate the surroundings of cool and hot stars, but also of more exotic objects like neutron stars. While pulsar wind nebulae (PWNs) might be a source of high-energy galactic cosmic rays (GCRs), the astrospheric environments of cool and hot stars form a natural shield against GCRs. Their modulation within these astrospheres, and the possible impact of turbulence, are also addressed. This review shows that all of the presented modeling efforts are in excellent agreement with currently available observations.
PubDate: 2022-05-13

• In Situ Observations of Interstellar Pickup Ions from 1 au to the Outer
Heliosphere

Abstract: Abstract Interstellar pickup ions are an ubiquitous and thermodynamically important component of the solar wind plasma in the heliosphere. These PUIs are born from the ionization of the interstellar neutral gas, consisting of hydrogen, helium, and trace amounts of heavier elements, in the solar wind as the heliosphere moves through the local interstellar medium. As cold interstellar neutral atoms become ionized, they form an energetic ring beam distribution comoving with the solar wind. Subsequent scattering in pitch angle by intrinsic and self-generated turbulence and their advection with the radially expanding solar wind leads to the formation of a filled-shell PUI distribution, whose density and pressure relative to the thermal solar wind ions grows with distance from the Sun. This paper reviews the history of in situ measurements of interstellar PUIs in the heliosphere. Starting with the first detection in the 1980s, interstellar PUIs were identified by their highly nonthermal distribution with a cutoff at twice the solar wind speed. Measurements of the PUI distribution shell cutoff and the He focusing cone, a downwind region of increased density formed by the solar gravity, have helped characterize the properties of the interstellar gas from near-Earth vantage points. The preferential heating of interstellar PUIs compared to the core solar wind has become evident in the existence of suprathermal PUI tails, the nonadiabatic cooling index of the PUI distribution, and PUIs’ mediation of interplanetary shocks. Unlike the Voyager and Pioneer spacecraft, New Horizon’s Solar Wind Around Pluto (SWAP) instrument is taking the only direct measurements of interstellar PUIs in the outer heliosphere, currently out to $$\sim47~\text{au}$$ from the Sun or halfway to the heliospheric termination shock.
PubDate: 2022-05-09

• Shocks in the Very Local Interstellar Medium

Abstract: Abstract Large-scale disturbances generated by the Sun’s dynamics first propagate through the heliosphere, influence the heliosphere’s outer boundaries, and then traverse and modify the very local interstellar medium (VLISM). The existence of shocks in the VLISM was initially suggested by Voyager observations of the 2-3 kHz radio emissions in the heliosphere. A couple of decades later, both Voyagers crossed the definitive edge of our heliosphere and became the first ever spacecraft to sample interstellar space. Since Voyager 1’s entrance into the VLISM, it sampled electron plasma oscillation events that indirectly measure the medium’s density, increasing as it moves further away from the heliopause. Some of the observed electron oscillation events in the VLISM were associated with the local heliospheric shock waves. The observed VLISM shocks were very different than heliospheric shocks. They were very weak and broad, and the usual dissipation via wave-particle interactions could not explain their structure. Estimates of the dissipation associated with the collisionality show that collisions can determine the VLISM shock structure. According to theory and models, the existence of a bow shock or wave in front of our heliosphere is still an open question as there are no direct observations yet. This paper reviews the outstanding observations recently made by the Voyager 1 and 2 spacecraft, and our current understanding of the properties of shocks/waves in the VLISM. We present some of the most exciting open questions related to the VLISM and shock waves that should be addressed in the future.
PubDate: 2022-05-09

• Correction to: Interstellar Neutrals, Pickup Ions, and Energetic Neutral
Atoms Throughout the Heliosphere: Present Theory and Modeling Overview

PubDate: 2022-05-05

• Recent Developments in Particle Acceleration at Shocks: Theory and
Observations

Abstract: Abstract Energetic particles represent an important component of the plasma in the heliosphere. They range from particles accelerated at impulsive events in the solar corona and at large scale structures in the interplanetary medium, to anomalous cosmic rays accelerated at the boundaries of the heliosphere. In-situ satellite observations, numerical simulations and theoretical models have advanced, often in a cooperative way, our knowledge on the acceleration processes involved. In this paper we review recent developments on particle acceleration, with major emphasis on shock acceleration, giving an overview of recent observations at interplanetary shocks and at the termination shock of the solar wind. We discuss their interpretation in terms of analytical models and numerical simulations. The influence of the particle transport properties on the acceleration mechanism will also be addressed.
PubDate: 2022-05-05

• Determining the Relative Cratering Ages of Regions of Psyche’s
Surface

Abstract: Abstract The study of the cratering history of asteroid (16) Psyche is one of the investigations to be performed by the NASA Psyche mission. A dedicated Relative Ages Working Group will carry on these investigations using primarily imaging and topographic data, and complement the interpretation of these data with theoretical models (hydrocodes to simulate impacts) as well as laboratory experiments (impact experiments on relevant target materials). The Psyche Science Team will also rely on experience and lessons learned from prior space missions, such as NASA Dawn and ESA Rosetta. The main goals of the cratering investigations are to map craters and characterize their morphology across Psyche’s surface over a range of spatial resolutions. These data will then be used to constrain relative and absolute ages of Psyche’s terrains, and impact-related processes will inform other investigations, such as geological mapping, surface composition, and internal structure. Psyche’s cratering data will also be used to perform comparative analyses with similar data from other rocky asteroids. The present chapter provides a pre-launch view of the planned activities and methodologies of the Relative Ages Working Group.
PubDate: 2022-05-02

• Neutrino-Flux Variability, Nuclear-Decay Variability, and Their Apparent
Relationship

Abstract: Abstract Analysis of Homestake, Gallex and GNO measurements reveals evidence of variability of presumed solar-neutrino-flux measurements. Analysis of Super-Kamiokande neutrino records over the interval May 1996 to July 2001 reveals oscillations at 9.43 year−1 and 12.6 year−1, both well within a range of frequencies (6–16 year−1) that, according to helioseismology, could be related to internal solar rotation. Analysis of the results of a nuclear-decay experiment carried out at the Brookhaven National Laboratory over the time interval 1982–1986 reveals a strong annual oscillation and also strong oscillations at 11.2 and 13.2 year−1, both of which would, according to helioseismology, be compatible with influences of internal solar rotation. Similar oscillations are found in an extensive series of nuclear-decay measurements conducted by Alexander Parkhomov of the Lomonosov Moscow State University and the Russian Academy of Natural Sciences. By contrast, as noted by Stefan Pomme of the European Commission Joint Research Centre and his colleagues, nuclear-decay measurements acquired at standards laboratories tend not to exhibit evidence of variability. The most extensive series of nuclear-decay measurements comes from an experiment initiated by the late Gideon Steinitz at the Geological Survey of Israel. This experiment, which was in operation from January 2007 to November 2016, recorded 340,000 lines of radon-related measurements from three gamma detectors and three environmental detectors (temperature, pressure, and line voltage). Analysis of a subset of 85,000 lines of hourly gamma measurements reveals overwhelmingly strong evidence of diurnal, annual and semi-annual oscillations and a number of oscillations with frequencies compatible with influences of internal solar rotation. There is no correlation between the gamma measurements and the environmental measurements. The rotational modulations may be attributed to an influence of the solar internal magnetic field by the RSFP (Resonant Spin-Flavor Precession) process. The detection of several pairs of oscillations separated by precisely 1 year−1 may be attributed to misalignments of internal rotation axes with respect to the normal to the ecliptic. A triplet of oscillations (at effectively 7.43, 8.43 and 9.43 year−1) may be attributed to an internal region (presumably the core) that has a sidereal rotation rate of 8.43 year−1 and a rotation axis approximately orthogonal to that of the solar photosphere. These results suggest that the Sun had its origin in more than one stage of condensation of interplanetary material (one on top of another), which would presumably lead to layers of the solar interior that have different metallicities, as well as different rotation rates and axes. It is remarkable that the oscillation at 9.43 year−1 occurs in both Superkamiokande and GSI data with the same amplitude and the same phase. Analysis of GSI data, together with a review of experiments conducted by Enrico Bellotti and his collaborators of the Instituto Nazionali di Fisica Nucleare, suggests that neutrinos do not influence decay rates, but do influence – presumably by a collective process - the direction of emission of decay products. This can help explain why the GSI experiment – for which decay products travel through air – gives evidence of strong modulation, whereas experiments at standards laboratories – for which decay products typically travel through comparatively dense media – do not. The peak modulation occurs near local midnight in early June, suggestive of a role of cosmic neutrinos. These neutrinos could provide the mass attributed to dark matter for a neutrino mass of order 0.1 eV.
PubDate: 2022-04-29

• Anomalous Cosmic Rays and Heliospheric Energetic Particles

Abstract: Abstract We present a review of Anomalous Cosmic Rays (ACRs), including the history of their discovery and recent insights into their acceleration and transport in the heliosphere. We focus on a few selected topics including a discussion of mechanisms of their acceleration, escape from the heliosphere, their effects on the dynamics of the heliosheath, transport in the inner heliosphere, and their solar cycle dependence. A discussion concerning their name is also presented towards the end of the review. We note that much is known about ACRs and perhaps the term Anomalous Cosmic Ray is not particularly descriptive to a non specialist. We suggest that the more-general term: “Heliospheric Energetic Particles”, which is more descriptive, for which ACRs and other energetic particle species of heliospheric origin are subsets, might be more appropriate.
PubDate: 2022-04-28

• Assessing the Sampleability of Bennu’s Surface for the OSIRIS-REx
Asteroid Sample Return Mission

Abstract: Abstract NASA’s first asteroid sample return mission, OSIRIS-REx, collected a sample from the surface of near-Earth asteroid Bennu in October 2020 and will deliver it to Earth in September 2023. Selecting a sample collection site on Bennu’s surface was challenging due to the surprising lack of large ponded deposits of regolith particles exclusively fine enough ( $$\leq2~\text{cm}$$ diameter) to be ingested by the spacecraft’s Touch-and-Go Sample Acquisition Mechanism (TAGSAM). Here we describe the Sampleability Map of Bennu, which was constructed to aid in the selection of candidate sampling sites and to estimate the probability of collecting sufficient sample. “Sampleability” is a numeric score that expresses the compatibility of a given area’s surface properties with the sampling mechanism. The algorithm that determines sampleability is a best fit functional form to an extensive suite of laboratory testing outcomes tracking the TAGSAM performance as a function of four observable properties of the target asteroid. The algorithm and testing were designed to measure and subsequently predict TAGSAM collection amounts as a function of the minimum particle size, maximum particle size, particle size frequency distribution, and the tilt of the TAGSAM head off the surface. The sampleability algorithm operated at two general scales, consistent with the resolution and coverage of data collected during the mission. The first scale was global and evaluated nearly the full surface. Due to Bennu’s unexpected boulder coverage and lack of ponded regolith deposits, the global sampleability efforts relied heavily on additional strategies to find and characterize regions of interest based on quantifying and avoiding areas heavily covered by material too large to be collected. The second scale was site-specific and used higher-resolution data to predict collected mass at a given contact location. The rigorous sampleability assessments gave the mission confidence to select the best possible sample collection site and directly enabled successful collection of hundreds of grams of material.
PubDate: 2022-04-19

• The Structure of the Global Heliosphere as Seen by In-Situ Ions from the
Voyagers and Remotely Sensed ENAs from Cassini

Abstract: Abstract The exploration of interplanetary space and our solar bubble, the heliosphere, has made a big leap over the past two decades, due to the path-breaking observations of the two Voyager spacecraft, launched more than 44 years ago. Their in-situ particle and fields measurements were complemented by remote observations of 5.2 to 55 keV Energetic Neutral Atoms (ENA) from the Cassini mission (Ion and Neutral Camera-INCA), revealing a number of previously unanticipated heliospheric structures such as the “Belt”, a region of enhanced particle pressure inside the heliosheath. The Suprathermal Time Of Flight (HSTOF) instrument on the Solar and Heliospheric Observatory (SOHO) also provided information of 58–88 keV ENAs from the heliosphere. In this chapter we provide a brief discussion for the contribution of the Voyager 1 and 2 Low Energy Charged Particle (LECP) observations that provided “ground truth” to the ENA images from Cassini/INCA towards addressing fundamental questions for the heliosphere’s interaction with the Very Local Interstellar Medium.
PubDate: 2022-04-19

• Interstellar Neutrals, Pickup Ions, and Energetic Neutral Atoms Throughout
the Heliosphere: Present Theory and Modeling Overview

Abstract: Abstract Interstellar neutrals (ISNs), pick-up ions (PUIs), and energetic neutral atoms (ENAs) are fundamental constituents of the heliosphere and its interaction with the neighboring interstellar medium. Here, we focus on selected aspects of present-day theory and modeling of these particles. In the last decades, progress in the understanding of the role of PUIs and ENAs for the global heliosphere and its interaction with very local interstellar medium is impressive and still growing. The increasing number of measurements allows for verification and continuing development of the theories and model attempts. We present an overview of various model descriptions of the heliosphere and the processes throughout it including the kinetic, fluid, and hybrid solutions. We also discuss topics in which interplay between theory, models, and interpretation of measurements reveals the complexity of the heliosphere and its understanding. They include model-based interpretation of the ISN, PUI, and ENA measurements conducted from the Earth’s vicinity. In addition, we describe selected processes beyond the Earth’s orbit up to the heliosphere boundary regions, where PUIs significantly contribute to the complex system of the global heliosphere and its interaction with the VLISM.
PubDate: 2022-04-13

• Design and Ground Verification for Multispectral Camera on the Mars
Tianwen-1 Rover

Abstract: Abstract As part of China’s first Mars exploration mission ‘Tianwen-1’, the Zhurong rover has successfully touched down on the surface of southern Utopia Planitia on May 15th 2021 and has been conducting surface operations for several months. A multispectral camera (MSCam), as an important payload onboard the Zhurong rover, aims to acquire multispectral images to investigate the morphological characteristics and mineralogic properties of the Martian surface. In this study, a detailed optimization design for the MSCam was carried out to achieve the abovementioned scientific objectives. The MSCam can perform multispectral imaging without chromatic aberration by utilizing eight narrow bandwidth filters made of glass of different thicknesses. Clear images of observation targets at different distances can be obtained by utilizing the six focal plane compensation lenses of varying thicknesses through the rotation of wheels. Calibration experiments, key specification tests and ground verification tests were also conducted in this study. Our results show that the pixel resolution of the MSCam can reach 0.146 mrad, the system static modulation transfer function (MTF) of the MSCam is better than 0.25@525 nm, and the signal-to-noise ratio (SNR) is higher than 40 dB, all of which allow clear imaging and accurate multispectral data acquisition of the targets. The high-resolution images obtained by the MSCam will provide detailed geological context for the data interpretation of other payloads on the rover, such as the Mars surface composition detector (MarSCoDe). The mineralogy information of the targets (e.g., fresh rock, dune) indicated by the MSCam multispectral data will also help to constrain the surface material composition of Mars.
PubDate: 2022-04-13

• Distinguishing the Origin of Asteroid (16) Psyche

Abstract: Abstract The asteroid (16) Psyche may be the metal-rich remnant of a differentiated planetesimal, or it may be a highly reduced, metal-rich asteroidal material that never differentiated. The NASA Psyche mission aims to determine Psyche’s provenance. Here we describe the possible solar system regions of origin for Psyche, prior to its likely implantation into the asteroid belt, the physical and chemical processes that can enrich metal in an asteroid, and possible meteoritic analogs. The spacecraft payload is designed to be able to discriminate among possible formation theories. The project will determine Psyche’s origin and formation by measuring any strong remanent magnetic fields, which would imply it was the core of a differentiated body; the scale of metal to silicate mixing will be determined by both the neutron spectrometers and the filtered images; the degree of disruption between metal and rock may be determined by the correlation of gravity with composition; some mineralogy (e.g., modeled silicate/metal ratio, and inferred existence of low-calcium pyroxene or olivine, for example) will be detected using filtered images; and the nickel content of Psyche’s metal phase will be measured using the GRNS.
PubDate: 2022-04-12

• Inhomogeneity in the Local ISM and Its Relation to the Heliosphere

Abstract: Abstract This paper reviews past research and new studies underway of the local interstellar environment and its changing influence on the heliosphere. The size, shape, and physical properties of the heliosphere outside of the heliopause are determined by the surrounding environment – now the outer region of the Local Interstellar Cloud (LIC). The temperature, turbulence, and velocity vector of neutral atoms and ions in the LIC and other partially ionized interstellar clouds are measured from high-resolution spectra of interstellar absorption lines observed with the STIS instrument on the HST. Analysis of such spectra led to a kinematic model with many interstellar clouds defined by velocity vectors derived from radial velocity measurements. This analysis identified fifteen clouds located within about 10 pc of the Sun and their mean temperatures, turbulence, and velocity vectors. With the increasing number of sight lines now being analyzed, we find that temperatures and turbulent velocities have spatial variations within the LIC and other nearby clouds much larger than measurement uncertainties, and that these spatial variations appear to be randomly distributed and can be fit by Gaussians. The inhomogeneous length scale is less than 4,000 AU, a distance that the heliosphere will traverse in less than 600 years. The temperatures and turbulent velocities do not show significant trends with stellar distance or angle from the LIC center. If/when the Sun enters an inter-cloud medium, the physical properties of the future heliosphere will be very different from the present. For the heliosheath and the very local interstellar medium (VLISM) just outside of the heliopause, the total pressures are approximately equal to the gravitational pressure of overlying material in the Galaxy. The internal pressure in the LIC is far below that in the VLISM, but there is an uncertain ram pressure term produced by the flow of the LIC with respect to its environment.
PubDate: 2022-04-12

• Editorial to the Topical Collection: Oscillatory Processes in Solar and
Stellar Coronae

PubDate: 2022-04-05

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