 Subjects -> AERONAUTICS AND SPACE FLIGHT (Total: 124 journals)
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- The Psyche Magnetometry Investigation
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Abstract: Abstract The objective of the Psyche Magnetometry Investigation is to test the hypothesis that asteroid (16) Psyche formed from the core of a differentiated planetesimal. To address this, the Psyche Magnetometer will measure the magnetic field around the asteroid to search for evidence of remanent magnetization. Paleomagnetic measurements of meteorites and dynamo theory indicate that a diversity of planetesimals once generated dynamo magnetic fields in their metallic cores. Likewise, the detection of a strong magnetic moment ( \(>2\times10^{14}~\text{Am}^{2}\) ) at Psyche would likely indicate that the body once generated a core dynamo, implying that it formed by igneous differentiation. The Psyche Magnetometer consists of two three-axis fluxgate Sensor Units (SUs) mounted 0.7 m apart along a 2.15-m long boom and connected to two Electronics Units (EUs) located within the spacecraft bus. The Magnetometer samples at up to 50 Hz, has a range of \(\pm80{,}000~\text{nT}\) , and an instrument noise of \(39~\text{pT}\,\text{axis}^{-1}\,3\sigma \) integrated over 0.1 to 1 Hz. The two pairs of SUs and EUs provide redundancy and enable gradiometry measurements to suppress noise from flight system magnetic fields. The Magnetometer will be powered on soon after launch and acquire data for the full duration of the mission. The ground data system processes the Magnetometer measurements to obtain an estimate of Psyche’s dipole moment.
PubDate: 2023-03-28
- In-Flight Performance of the ICON EUV Spectrograph
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Abstract: Abstract We present in-flight performance measurements of the Ionospheric Connection Explorer EUV spectrometer, ICON EUV, a wide field ( \(17^{\circ} \times 12^{\circ} \) ) extreme ultraviolet (EUV) imaging spectrograph designed to observe the lower ionosphere at tangent altitudes between 100 and 500 km. The primary targets of the spectrometer, which has a spectral range of 54–88 nm, are the Oii emission lines at 61.6 nmand 83.4 nm. In flight calibration and performance measurement has shown that the instrument has met all of the science performance requirements. We discuss the observed and expected changes in the instrument performance due to microchannel plate charge depletion, and how these changes were tracked over the first two years of flight. This paper shows raw data products from this instrument. A parallel paper (Stephan et al. in Space Sci. Rev. 218:63, 2022) in this volume discusses the use of these raw products to determine O+ density profiles versus altitude.
PubDate: 2023-03-28
- Update of ICON-FUV hmF2 and NmF2 Comparison with External Radio
Observations-
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Abstract: Abstract The Far Ultraviolet Imaging Spectrograph (FUV) onboard the NASA-ICON spacecraft has been providing nighttime O+ density profiles over mid- and low-latitude since December 2019. These profiles are compared to electron density profiles provided by GNSS radio-occultations and ground-based ionosondes, mainly at the F-peak level where both density and height are compared. This work is an important update of the earlier study published by Wautelet et al. (J. Geophys. Res. Space Phys. 126(11):e2021JA029360, 2021) for two reasons: First, several methodological improvements have been implemented at the calibration and inversion levels. Second, the present work relies on an extended time range, ranging from December 2019 to August 2022, covering therefore periods of increased solar activity, which was not the case for the previous work. It is found that the peak density and height are, on average, similar to radio-based observations by about 10% in density and 7 km in height, meaning that FUV provides peak characteristics compatible with existing ionospheric datasets based on radio signals. However, comparisons of FUV and radio-occultation profiles have to be considered very carefully due to the potentially large difference in the observation geometry, which can account for large density discrepancies even between profiles being closely located and mostly simultaneous. This is particularly important around the crests of the equatorial anomaly where the largest density discrepancies have been observed. In addition, this study highlights the variability of the FUV profiles at the bottomside level, with the analysis of cases where rather large density values were observed while small density values are expected. The latter observation does nevertheless not impact the statistics concerning the F-peak characteristics, which show that FUV reliably monitors the peak density and height with an accuracy compatible to that of external data sources.
PubDate: 2023-03-28
- In Flight Performance of the Far Ultraviolet Instrument (FUV) on ICON
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Abstract: Abstract The NASA Ionospheric Connection Explorer (ICON) was launched in October 2019 and has been observing the upper atmosphere and ionosphere to understand the sources of their strong variability, to understand the energy and momentum transfer, and to determine how the solar wind and magnetospheric effects modify the internally-driven atmosphere-space system. The Far Ultraviolet Instrument (FUV) supports these goals by observing the ultraviolet airglow in day and night, determining the atmospheric and ionospheric composition and density distribution. Based on the combination of ground calibration and flight data, this paper describes how major instrument parameters have been verified or refined since launch, how science data are collected, and how the instrument has performed over the first 3 years of the science mission. It also provides a brief summary of science results obtained so far.
PubDate: 2023-03-28
- Results from InSight Robotic Arm Activities
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Abstract: Abstract The InSight lander carried an Instrument Deployment System (IDS) that included an Instrument Deployment Arm (IDA), scoop, five finger “claw” grapple, forearm-mounted Instrument Deployment Camera (IDC) requiring arm motion to image a target, and lander-mounted Instrument Context Camera (ICC), designed to image the workspace, and to place the instruments onto the surface. As originally proposed, the IDS included a previously built arm and flight spare black and white cameras and had no science objectives or requirements, or expectation to be used after instrument deployment (90 sols). During project development the detectors were upgraded to color, and it was recognized that the arm could be used to carry out a wide variety of activities that would enable both geology and physical properties investigations. During surface operations for two martian years, the IDA was used during major campaigns to image the surface around the lander, to deploy the instruments, to assist the mole in penetrating beneath the surface, to bury a portion of the seismometer tether, to clean dust from the solar arrays to increase power, and to conduct a surface geology investigation including soil mechanics and physical properties experiments. No other surface mission has engaged in such a sustained and varied campaign of arm and scoop activities directed at such a diverse suite of objectives. Images close to the surface and continuous meteorology measurements provided important constraints on the threshold friction wind speed needed to initiate aeolian saltation and surface creep. The IDA was used extensively for almost 22 months to assist the mole in penetrating into the subsurface. Soil was scraped into piles and dumped onto the seismometer tether six times in an attempt to bury the tether and \(\sim30\%\) was entrained in the wind and dispersed downwind 1-2 m, darkening the surface. Seven solar array cleaning experiments were conducted by dumping scoops of soil from 35 cm above the lander deck during periods of high wind that dispersed the sand onto the panels that kicked dust off of the panels into suspension in the atmosphere, thereby increasing the power by ∼15% during this period. Final IDA activities included an indentation experiment that used the IDA scoop to push on the ground to measure the plastic deformation of the soil that complemented soil mechanics measurements from scoop interactions with the surface, and two experiments in which SEIS measured the tilt from the arm pressing on the ground to derive near surface elastic properties.
PubDate: 2023-03-20
- Long-Term Modulation of Solar Cycles
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Abstract: Abstract Solar activity has a cyclic nature with the ≈11-year Schwabe cycle dominating its variability on the interannual timescale. However, solar cycles are significantly modulated in length, shape and magnitude, from near-spotless grand minima to very active grand maxima. The ≈400-year-long direct sunspot-number series is inhomogeneous in quality and too short to study robust parameters of long-term solar variability. The cosmogenic-isotope proxy extends the timescale to twelve millennia and provides crucial observational constraints of the long-term solar dynamo modulation. Here, we present a brief up-to-date overview of the long-term variability of solar activity at centennial – millennial timescales. The occurrence of grand minima and maxima is discussed as well as the existing quasi-periodicities such as centennial Gleissberg, 210-year Suess/de Vries and 2400-year Hallstatt cycles. It is shown that the solar cycles contain an important random component and have no clock-like phase locking implying a lack of long-term memory. A brief yet comprehensive review of the theoretical perspectives to explain the observed features in the framework of the dynamo models is presented, including the nonlinearity and stochastic fluctuations in the dynamo. We keep gaining knowledge of the processes driving solar variability with the new data acquainted and new models developed.
PubDate: 2023-03-17
- Future Exploration of the Outer Heliosphere and Very Local Interstellar
Medium by Interstellar Probe-
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Abstract: Abstract A detailed overview of the knowledge gaps in our understanding of the heliospheric interaction with the largely unexplored Very Local Interstellar Medium (VLISM) are provided along with predictions of with the scientific discoveries that await. The new measurements required to make progress in this expanding frontier of space physics are discussed and include in-situ plasma and pick-up ion measurements throughout the heliosheath, direct sampling of the VLISM properties such as elemental and isotopic composition, densities, flows, and temperatures of neutral gas, dust and plasma, and remote energetic neutral atom (ENA) and Lyman-alpha (LYA) imaging from vantage points that can uniquely discern the heliospheric shape and bring new information on the interaction with interstellar hydrogen. The implementation of a pragmatic Interstellar Probe mission with a nominal design life to reach 375 Astronomical Units (au) with likely operation out to 550 au are reported as a result of a 4-year NASA funded mission study.
PubDate: 2023-02-28
- The Habitability of Venus
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Abstract: Abstract Venus today is inhospitable at the surface, its average temperature of 750 K being incompatible to the existence of life as we know it. However, the potential for past surface habitability and upper atmosphere (cloud) habitability at the present day is hotly debated, as the ongoing discussion regarding a possible phosphine signature coming from the clouds shows. We review current understanding about the evolution of Venus with special attention to scenarios where the planet may have been capable of hosting microbial life. We compare the possibility of past habitability on Venus to the case of Earth by reviewing the various hypotheses put forth concerning the origin of habitable conditions and the emergence and evolution of plate tectonics on both planets. Life emerged on Earth during the Hadean when the planet was dominated by higher mantle temperatures (by about \(200~^{\circ}\text{C}\) ), an uncertain tectonic regime that likely included squishy lid/plume-lid and plate tectonics, and proto continents. Despite the lack of well-preserved crust dating from the Hadean and Paleoarchean, we attempt to review current understanding of the environmental conditions during this critical period based on zircon crystals and geochemical signatures from this period, as well as studies of younger, relatively well-preserved rocks from the Paleoarchean. For these early, primitive life forms, the tectonic regime was not critical but it became an important means of nutrient recycling, with possible consequences on the global environment in the long-term, that was essential to the continuation of habitability and the evolution of life. For early Venus, the question of stable surface water is closely related to tectonics. We discuss potential transitions between stagnant lid and (episodic) tectonics with crustal recycling, as well as consequences for volatile cycling between Venus’ interior and atmosphere. In particular, we review insights into Venus’ early climate and examine critical questions about early rotation speed, reflective clouds, and silicate weathering, and summarize implications for Venus’ long-term habitability. Finally, the state of knowledge of the Venusian clouds and the proposed detection of phosphine is covered.
PubDate: 2023-02-22
- A Brief Review of Equatorial Plasma Bubbles
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Abstract: Abstract Equatorial plasma bubbles (EPBs) have long been studied and are becoming increasingly important because they cause severe scintillations in radio waves from Global Navigation Satellite System (GNSS) satellites. In this review paper EPBs and their characteristics like generation mechanism, initial perturbation, occurrence variability, zonal drift velocity, vertical rise velocity, coupling with zonal neutral winds and secondary instabilities are thoroughly reviewed, and future aspects are discussed.
PubDate: 2023-02-15
- Internal and External Jovian Magnetic Fields: Community Code to Serve the
Magnetospheres of the Outer Planets Community-
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Abstract: Abstract We report on a new international community coding project to provide shared scientific computer code that performs common calculations to aid in planning scientific observations, modeling, and data analysis. We have developed code which calculates Jupiter’s internal and external magnetic fields. All magnetic field model code is provided in four programming languages (C++, IDL, MATLAB and Python). The code is freely available on GitHub. For Jupiter’s internal magnetic field, we present a number of spherical harmonic internal magnetic field models. These include JRM33, the latest Jupiter internal magnetic field model (Connerney et al. in J. Geophys. Res., Planets 127(2):e07055, 2022), as well as older jovian models (e.g. JRM09 (Connerney et al. in Geophys. Res. Lett. 45(6):2590–2596, 2018), O6 (Connerney in Planetary Radio Emissions III, pp. 13–33, 1992), VIP4 (Connerney et al. in J. Geophys. Res. 103(A6):11,929–11,940, 1998) and VIPAL (Hess et al. in J. Geophys. Res. Space Phys. 116(A5):A05217, 2011)). The internal magnetic field code can be easily modified for other planets by simply inputting another spherical harmonic magnetic field model. We have also developed code to calculate the magnetic field perturbations due to the azimuthal and radial currents flowing externally around Jupiter in the jovian magnetodisc according to the model of Connerney et al. (J. Geophys. Res. 86(A10):8370–8384, 1981; J. Geophys. Res. Space Phys. 125(10):e28138, 2020). The internal and external magnetic field codes can be combined to model the magnetic field in Jupiter’s magnetosphere. Finally, we provide field-line tracing software (C++ and a Python wrapper for C++) that utilizes the internal and external magnetic field models. The software can be used to trace along field lines from any position in the jovian magnetosphere to, for example, the ionosphere or an equator, and can also be utilized at different planets.
PubDate: 2023-02-13
- Synergies Between Venus & Exoplanetary Observations
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Abstract: Abstract Here we examine how our knowledge of present day Venus can inform terrestrial exoplanetary science and how exoplanetary science can inform our study of Venus. In a superficial way the contrasts in knowledge appear stark. We have been looking at Venus for millennia and studying it via telescopic observations for centuries. Spacecraft observations began with Mariner 2 in 1962 when we confirmed that Venus was a hothouse planet, rather than the tropical paradise science fiction pictured. As long as our level of exploration and understanding of Venus remains far below that of Mars, major questions will endure. On the other hand, exoplanetary science has grown leaps and bounds since the discovery of Pegasus 51b in 1995, not too long after the golden years of Venus spacecraft missions came to an end with the Magellan Mission in 1994. Multi-million to billion dollar/euro exoplanet focused spacecraft missions such as JWST, and its successors will be flown in the coming decades. At the same time, excitement about Venus exploration is blooming again with a number of confirmed and proposed missions in the coming decades from India, Russia, Japan, the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA). Here we review what is known and what we may discover tomorrow in complementary studies of Venus and its exoplanetary cousins.
PubDate: 2023-02-09
- How Do Shock Waves Define the Space-Time Structure of Gradual Solar
Energetic Particle Events'-
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Abstract: Abstract We revisit the full variety of observed temporal and spatial distributions of energetic solar protons in “gradual” solar energetic-particle (SEP) events resulting from the spatial variations in the shock waves that accelerate them. Differences in the shock strength at the solar longitude of a spacecraft and at the footpoint of its connecting magnetic field line, curved by solar rotation nominally \(55^{\circ}\) to the west, drive much of that variation. The shock wave itself, together with energetic particles trapped near it by self-amplified hydromagnetic or Alfvén waves, forms an underlying autonomous structure. This structure can drive across magnetic field lines intact, spreading proton intensities in a widening SEP longitude distribution. During the formation of this fundamental structure, historically called an “energetic storm particle” (ESP) event, many SEPs leak away early, amplifying waves as they flow along well-connected field lines and broaden the distribution outward; behind the structure, between the shock and the Sun, a “reservoir” of quasi-trapped SEPs forms. Very large SEP events are complicated by additional extensive wave growth that can spread an extended ESP-like trapping region around the Sun throughout most of the pre-shock event. Here SEP intensities are bounded at the “streaming limit,” a balance between proton streaming, which amplifies waves, and scattering, which reduces the streaming. The multiplicity of shock-related processes contributing to the observed SEP profiles causes correlations of the events to be poorly represented by the single peak intensity commonly used. In fact, the extensive spatial distributions of SEPs are sometimes free and sometimes interwoven with the structures of the shocks that have accelerated them. We should consider new questions: Which extremes of the shock contribute most to a local SEPs profile of an event, (1) the shock at the longitude of a spacecraft, (2) the shock \(\sim55^{\circ}\) to the west at the footpoint of the field, or (3) SEPs that have collected in the reservoir' How does the space-time distribution of SEPs correspond with the underlying space-time distribution of shock strength'
PubDate: 2023-02-09
- Protoplanetary Disk Science with the Orbiting Astronomical Satellite
Investigating Stellar Systems (OASIS) Observatory-
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Abstract: Abstract The Orbiting Astronomical Satellite for Investigating Stellar Systems (OASIS) is a NASA Astrophysics MIDEX-class mission concept, with the stated goal of Following water from galaxies, through protostellar systems, to Earth’s oceans. This paper details the protoplanetary disk science achievable with OASIS. OASIS’s suite of heterodyne receivers allow for simultaneous, high spectral resolution observations of water emission lines spanning a large range of physical conditions within protoplanetary disks. These observations will allow us to map the spatial distribution of water vapor in disks across evolutionary stages and assess the importance of water, particularly the location of the midplane water snowline, to planet formation. OASIS will also detect the H2 isotopologue HD in 100+ disks, allowing for the most accurate determination of total protoplanetary disk gas mass to date. When combined with the contemporaneous water observations, the HD detection will also allow us to trace the evolution of water vapor across evolutionary stages. These observations will enable OASIS to characterize the time development of the water distribution and the role water plays in the process of planetary system formation.
PubDate: 2023-02-07
- Venus, the Planet: Introduction to the Evolution of Earth’s Sister
Planet-
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Abstract: Abstract Venus is the planet in the Solar System most similar to Earth in terms of size and (probably) bulk composition. Until the mid-20th century, scientists thought that Venus was a verdant world—inspiring science-fictional stories of heroes battling megafauna in sprawling jungles. At the start of the Space Age, people learned that Venus actually has a hellish surface, baked by the greenhouse effect under a thick, CO2-rich atmosphere. In popular culture, Venus was demoted from a jungly playground to (at best) a metaphor for the redemptive potential of extreme adversity. However, whether Venus was much different in the past than it is today remains unknown. In this review, we show how now-popular models for the evolution of Venus mirror how the scientific understanding of modern Venus has changed over time. Billions of years ago, Venus could have had a clement surface with water oceans. Venus perhaps then underwent at least one dramatic transition in atmospheric, surface, and interior conditions before present day. This review kicks off a topical collection about all aspects of Venus’s evolution and how understanding Venus can teach us about other planets, including exoplanets. Here we provide the general background and motivation required to delve into the other manuscripts in this collection. Finally, we discuss how our ignorance about the evolution of Venus motivated the prioritization of new spacecraft missions that will rediscover Earth’s nearest planetary neighbor—beginning a new age of Venus exploration.
PubDate: 2023-02-06
- Pre-flight Geometric and Optical Calibration of the Planetary Instrument
for X-ray Lithochemistry (PIXL)-
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Abstract: Abstract The Planetary Instrument for X-ray Lithochemistry (PIXL) is a micro-focus X-ray fluorescence spectrometer that is mounted on the robotic arm of NASA’s Perseverance rover. PIXL scans target surfaces with high spacial resolution yielding detailed analyses of rock or soil elemental chemistry. The elemental maps are produced by a narrow 120 μm X-ray beam. These scans are correlated to images captured by PIXL’s Micro Context Camera (MCC) which tie the X-ray measurements to the visual texture and structure of the sample, revealing the distribution and variations of chemical elements within the rock. The PIXL subsystem that determines this correspondence is the Optical Fiducial System (OFS), which is comprised of the MCC, two Structured Light Illuminators (SLI) and a Floodlight Illuminator (FLI). This paper discusses the pre-flight calibration of the OFS, including optical calibration of the MCC, radiometric calibration of the floodlight system and geometric calibration of the structured light illumination beam together with an overall geometric calibration of the OFS and the X-ray beam. Finally, results from the performance verification are presented.
PubDate: 2023-02-06
- Extragalactic Science with the Orbiting Astronomical Satellite
Investigating Stellar Systems (OASIS) Observatory-
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Abstract: Abstract The Orbiting Astronomical Satellite for Investigating Stellar Systems (OASIS), a proposed Astrophysics MIDEX-class mission concept, has an innovative 14-meter diameter inflatable primary mirror that will provide the sensitivity to study far-infrared continuum and line emission from galaxies at all redshifts with high spectral resolution heterodyne receivers. OASIS will have the sensitivity to follow the water trail from galaxies to the comets that create oceans. It will bring an understanding of the role of water in galaxy evolution and its part of the oxygen budget, by measuring water emission from local to intermediate redshift galaxies, observations that have not been possible from the ground. Observation of the ground-state HD line will accurately measure gas mass in a wide variety of astrophysical objects. Thanks to its exquisite spatial resolution and sensitivity, OASIS will, during its one-year baseline mission, detect water in galaxies with unprecedented statistical significance. This paper reviews the extragalactic science achievable and planned with OASIS.
PubDate: 2023-02-02
- Parker Solar Probe: Four Years of Discoveries at Solar Cycle Minimum
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Abstract: Abstract Launched on 12 Aug. 2018, NASA’s Parker Solar Probe had completed 13 of its scheduled 24 orbits around the Sun by Nov. 2022. The mission’s primary science goal is to determine the structure and dynamics of the Sun’s coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what processes accelerate energetic particles. Parker Solar Probe returned a treasure trove of science data that far exceeded quality, significance, and quantity expectations, leading to a significant number of discoveries reported in nearly 700 peer-reviewed publications. The first four years of the 7-year primary mission duration have been mostly during solar minimum conditions with few major solar events. Starting with orbit 8 (i.e., 28 Apr. 2021), Parker flew through the magnetically dominated corona, i.e., sub-Alfvénic solar wind, which is one of the mission’s primary objectives. In this paper, we present an overview of the scientific advances made mainly during the first four years of the Parker Solar Probe mission, which go well beyond the three science objectives that are: (1) Trace the flow of energy that heats and accelerates the solar corona and solar wind; (2) Determine the structure and dynamics of the plasma and magnetic fields at the sources of the solar wind; and (3) Explore mechanisms that accelerate and transport energetic particles.
PubDate: 2023-02-01
- Herbig Stars
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Abstract: Abstract Herbig Ae/Be stars are young contracting stars on the radiative track in the HR diagram on their way to the main sequence. These stars provide a valuable link between high and low mass stars. Here we review the progress that has been made in our understanding of these fascinating objects and their disks since the last major review on this topic published in 1998. We begin with a general overview of these stars and their properties. We then discuss the accretion of circumstellar material onto these stars. Next we discuss the dust and gas properties of the circumstellar disk before exploring the evidence for planet formation in these disks. We conclude with a brief discussion of future prospects for deepening our understanding of these sources and propose a new working definition of Herbig Ae/Be stars.
PubDate: 2023-01-31
- The Heliosphere in the Local Interstellar Medium: Into the Unknown
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PubDate: 2023-01-30
- The Mars Microphone Onboard SuperCam
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Abstract: Abstract The “Mars Microphone” is one of the five measurement techniques of SuperCam, an improved version of the ChemCam instrument that has been functioning aboard the Curiosity rover for several years. SuperCam is located on the rover’s Mast Unit, to take advantage of the unique pointing capabilities of the rover’s head. In addition to being the first instrument to record sounds on Mars, the SuperCam Microphone can address several original scientific objectives: the study of sound associated with laser impacts on Martian rocks to better understand their mechanical properties, the improvement of our knowledge of atmospheric phenomena at the surface of Mars such as atmospheric turbulence, convective vortices, dust lifting processes and wind interactions with the rover itself. The microphone also helps our understanding of the sound signature of the different movements of the rover: operations of the robotic arm and the mast, driving on the rough surface of Mars, monitoring of the pumps, etc. The SuperCam Microphone was delivered to the SuperCam team in early 2019 and integrated at the Jet Propulsion Laboratory (JPL), Pasadena, CA with the complete SuperCam instrument. The Mars 2020 Mission launched in July 2020 and landed on Mars on February 18, 2021. The mission operations are expected to last until at least August 2023. The microphone is operating perfectly.
PubDate: 2023-01-24
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