Journal: Space Science Reviews

Abbreviation

Space Sci. Rev.

Publisher

Springer

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ISSN

1572-9672
0038-6308

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Publications 1 - 10 of 68
  • The Dynamics of the Extreme Ultraviolet Quiet Sun and Coronal Holes in the Solar Orbiter Era
    Item type: Review Article
    Harra, Louise; Barczynski, Krzysztof; Auchère, Frédéric; et al. (2025)
    Space Science Reviews
    The quiet Sun corona and coronal holes, as seen in the extreme ultraviolet (EUV), host a variety of phenomena that operate over a range of spatial and temporal scales. Dynamic brightenings and jets of at most a few megameters appear to evolve on minute timescales. Coronal structures larger than tens of Mm evolve on much longer, hour timescales. Understanding the characteristics of the quiet Sun corona and coronal holes along with their disparate phenomena will provide important constraints on models that aim to explain how the plasma is heated and how it further expands to form the solar wind. In 2020, the European Space Agency (ESA) Solar Orbiter mission was launched. It features a comprehensive remote-sensing package, which includes two instruments observing in the Extreme Ultraviolet (EUV) and UV spectrometer data: the Extreme Ultraviolet Imager (EUI) that provides high resolution Extreme Ultraviolet (EUV) images at 174 $\mathring{A}$; (HRI$_{EUV}$), and the Spectral Imaging of the Coronal Environment (SPICE) spectrometer that enables plasma diagnostics, and the Polarimetric and Helioseismic Imager (PHI) that measures the photospheric magnetic field. These data, alongside a fleet of instruments on the Solar Dynamics Observatory (SDO), Hinode and the Interface Region Imaging Spectrograph (IRIS), are providing new information on the behaviour and dynamics of the quiet Sun and coronal holes. We will review the latest results and put them in context of describing the physics of coronal heating and solar wind formation.
  • Physicochemical Controls on the Compositions of the Earth and Planets
    Item type: Journal Article
    Sossi , Paolo A.; Hin , Remco C.; Kleine , Thorsten; et al. (2025)
    Space Science Reviews
    Despite the fact that the terrestrial planets all formed from the protoplanetary disk, their bulk compositions show marked departures from that of material condensing from a canonical H2-rich solar nebula. Metallic cores fix the oxygen fugacities (fO2s) of the planets to between ∼5 (Mercury) and ∼1 log units below the iron-wüstite (IW) buffer, orders of magnitude higher than that of the nebular gas. Their oxidised character is coupled with a lack of volatile elements with respect to the solar nebula. Here we show that condensates from a canonical solar gas at different temperatures (T0) produce bulk compositions with Fe/O (by mass) ranging from ∼0.93 (T0=1250 K) to ∼0.81 (T0=400 K), far lower than that of Earth at 1.06. Because the reaction Fe(s) + H2O(g) = FeO(s) + H2(g) proceeds only below ∼600 K, temperatures at which most moderately volatile elements (MVEs) have already condensed, oxidised planets are expected to be rich in volatiles, and vice-versa. That this is not observed suggests that planets i) did not accrete from equilibrium nebular condensates and/or ii) underwent additional volatile depletion/fO2 changes at conditions distinct from those of the solar nebula. Indeed, MVE abundances in small telluric bodies (Moon, Vesta) are consistent with evaporation/condensation at ΔIW-1 and ∼1400–1800 K, while the extent of mass-dependent isotopic fractionation observed implies this occurred near- or at equilibrium. On the other hand, the volatile-depleted elemental- yet near-chondritic isotopic compositions of larger telluric bodies (Earth, Mars) reflect mixing of bodies that had themselves experienced different extents of volatile depletion, overprinted by accretion of volatile-undepleted material. On the basis of isotopic anomalies in Cr- and Ti in the BSE, such undepleted matter has been proposed to be CI chondrites, which would comprise 40% by mass if the proto-Earth were ureilite-like. However, this would result in an overabundance of volatile elements in the BSE, requiring significant loss thereafter, which has yet to be demonstrated. On the other hand, 6% CI material added late to an enstatite chondrite-like proto-Earth would broadly match the BSE composition. However, because the Earth is an end-member in isotopic anomalies of heavier elements, no combination of existing meteorites alone can account for its chemical- and isotopic composition. Instead, the Earth is most likely made partially or essentially entirely from an NC-like missing component. If so, the oxidised-, yet volatile-poor nature of differentiated bodies in the inner solar system, including Earth and Mars, is a property intrinsic to the NC reservoir.
  • The InSight HP³ Penetrator (Mole) on Mars: Soil Properties Derived from the Penetration Attempts and Related Activities
    Item type: Journal Article
    Spohn, Tilman; Hudson, Troy L.; Marteau, Eloïse; et al. (2022)
    Space Science Reviews
    The NASA InSight Lander on Mars includes the Heat Flow and Physical Properties Package HP3 to measure the surface heat flow of the planet. The package uses temperature sensors that would have been brought to the target depth of 3–5 m by a small penetrator, nicknamed the mole. The mole requiring friction on its hull to balance remaining recoil from its hammer mechanism did not penetrate to the targeted depth. Instead, by precessing about a point midway along its hull, it carved a 7 cm deep and 5–6 cm wide pit and reached a depth of initially 31 cm. The root cause of the failure – as was determined through an extensive, almost two years long campaign – was a lack of friction in an unexpectedly thick cohesive duricrust. During the campaign – described in detail in this paper – the mole penetrated further aided by friction applied using the scoop at the end of the robotic Instrument Deployment Arm and by direct support by the latter. The mole tip finally reached a depth of about 37 cm, bringing the mole back-end 1–2 cm below the surface. It reversed its downward motion twice during attempts to provide friction through pressure on the regolith instead of directly with the scoop to the mole hull. The penetration record of the mole was used to infer mechanical soil parameters such as the penetration resistance of the duricrust of 0.3–0.7 MPa and a penetration resistance of a deeper layer (> 30 cm depth) of 4.9±0.4 MPa. Using the mole’s thermal sensors, thermal conductivity and diffusivity were measured. Applying cone penetration theory, the resistance of the duricrust was used to estimate a cohesion of the latter of 2–15 kPa depending on the internal friction angle of the duricrust. Pushing the scoop with its blade into the surface and chopping off a piece of duricrust provided another estimate of the cohesion of 5.8 kPa. The hammerings of the mole were recorded by the seismometer SEIS and the signals were used to derive P-wave and S-wave velocities representative of the topmost tens of cm of the regolith. Together with the density provided by a thermal conductivity and diffusivity measurement using the mole’s thermal sensors, the elastic moduli were calculated from the seismic velocities. Using empirical correlations from terrestrial soil studies between the shear modulus and cohesion, the previous cohesion estimates were found to be consistent with the elastic moduli. The combined data were used to derive a model of the regolith that has an about 20 cm thick duricrust underneath a 1 cm thick unconsolidated layer of sand mixed with dust and above another 10 cm of unconsolidated sand. Underneath the latter, a layer more resistant to penetration and possibly containing debris from a small impact crater is inferred. The thermal conductivity increases from 14 mW/m K to 34 mW/m K through the 1 cm sand/dust layer, keeps the latter value in the duricrust and the sand layer underneath and then increases to 64 mW/m K in the sand/gravel layer below.
  • Accretion of the Earth-Missing Components?
    Item type: Review Article
    Mezger, Klaus; Schönbächler, Maria; Bouvier, Audrey (2020)
    Space Science Reviews
    Primitive meteorites preserve the chemical and isotopic composition of the first aggregates that formed from dust and gas in the solar nebula during the earliest stages of solar system evolution. Gradual increase in the size of solid bodies from dust to aggregates and then to planetesimals finally led to the formation of planets within a few to tens of million years after the start of condensation. Thus the rocky planets of the inner solar system are likely the result of the accumulation of numerous smaller primitive as well as differentiated bodies. The chemically most primitive known meteorites are chondrites and they consist mostly of metal and silicates. Chondritic meteorites are derived from distinct primitive planetary bodies that experienced only limited element fractionation during formation and subsequent differentiation. Different chondrite classes show distinct chemical and isotopic characteristics, which may reflect heterogeneities in the solar nebula and the slightly different pathways of their formation. To a first approximation the chemical composition of the bulk Earth bears great similarities to primitive meteorites. However, for some elements there are striking and significant differences. The Earth shows a much stronger depletion of the moderate to highly volatile elements compared to chondrites. In addition, mixing trends of specific isotopes reveal that the Earth is most enriched in 𝑠��-process isotopes compared to all other analysed bulk solar system materials. It is currently not possible to fully define and quantify the different chemical and isotopic materials that formed the Earth, because a major component seems missing in the extant collections of extraterrestrial samples. Variations in nucleosynthetic isotope compositions as well as the strong depletion of moderately and strongly volatile elements points towards a source in the inner solar system for this missing material. It is conceivable that Venus and Mercury contain a much larger fraction of this missing component. Thus, for a complete reconstruction of the conditions that led to the formation of the inner solar system planets (Mercury to Mars) samples from the inner planets Venus and Mercury are of great interest and importance. High precision chemical and isotopic analyses in the laboratory of rocky material from inner solar system bodies could complete the knowledge on the chemical, isotopic and mineralogical make-up of the solar nebula just prior to planet formation and enhance our understanding of the evolution of the solar nebula in general and the formation of the rocky planets in particular.
  • Future Exploration of the Outer Heliosphere and Very Local Interstellar Medium by Interstellar Probe
    Item type: Journal Article
    Brandt, Pontus; Provornikova, Elena; Bale, Stuart D.; et al. (2023)
    Space Science Reviews
    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.
  • Small-Scale Solar Magnetic Fields
    Item type: Journal Article
    Wijn, Alfred G. de; Stenflo, Jan Olof; Solanki, Sami K.; et al. (2009)
    Space Science Reviews
  • Geomagnetic Jerks
    Item type: Journal Article
    Mandea, Mioara; Holme, Richard; Pais, Alexandra; et al. (2010)
    Space Science Reviews
  • Magma Ocean, Water, and the Early Atmosphere of Venus
    Item type: Review Article
    Salvador, Arnaud; Avice, Guillaume; Breuer, Doris; et al. (2023)
    Space Science Reviews
    The current state and surface conditions of the Earth and its twin planet Venus are drastically different. Whether these differences are directly inherited from the earliest stages of planetary evolution, when the interior was molten, or arose later during the long-term evolution is still unclear. Yet, it is clear that water, its abundance, state, and distribution between the different planetary reservoirs, which are intimately related to the solidification and outgassing of the early magma ocean, are key components regarding past and present-day habitability, planetary evolution, and the different pathways leading to various surface conditions. In this chapter we start by reviewing the outcomes of the accretion sequence, with particular emphasis on the sources and timing of water delivery in light of available constraints, and the initial thermal state of Venus at the end of the main accretion. Then, we detail the processes at play during the early thermo-chemical evolution of molten terrestrial planets, and how they can affect the abundance and distribution of water within the different planetary reservoirs. Namely, we focus on the magma ocean cooling, solidification, and concurrent formation of the outgassed atmosphere. Accounting for the possible range of parameters for early Venus and based on the mechanisms and feedbacks described, we provide an overview of the likely evolutionary pathways leading to diverse surface conditions, from a temperate to a hellish early Venus. The implications of the resulting surface conditions and habitability are discussed in the context of the subsequent long-term interior and atmospheric evolution. Future research directions and observations are proposed to constrain the different scenarios in order to reconcile Venus’ early evolution with its current state, while deciphering which path it followed.
  • Geology and Physical Properties Investigations by the InSight Lander
    Item type: Review Article
    Golombek, Matthew; Grott, Matthias; Kargl, Günter; et al. (2018)
    Space Science Reviews
  • SEIS: Insight’s Seismic Experiment for Internal Structure of Mars
    Item type: Journal Article
    Lognonne, Philippe; Giardini, Domenico; Zweifel, Peter; et al. (2019)
    Space Science Reviews
    By the end of 2018, 42 years after the landing of the two Viking seismometers on Mars, InSight will deploy onto Mars’ surface the SEIS (Seismic Experiment for Internal Structure) instrument; a six-axes seismometer equipped with both a long-period three-axes Very Broad Band (VBB) instrument and a three-axes short-period (SP) instrument. These six sensors will cover a broad range of the seismic bandwidth, from 0.01 Hz to 50 Hz, with possible extension to longer periods. Data will be transmitted in the form of three continuous VBB components at 2 sample per second (sps), an estimation of the short period energy content from the SP at 1 sps and a continuous compound VBB/SP vertical axis at 10 sps. The continuous streams will be augmented by requested event data with sample rates from 20 to 100 sps. SEIS will improve upon the existing resolution of Viking’s Mars seismic monitoring by a factor of ∼2500 at 1 Hz and ∼200000 at 0.1 Hz. An additional major improvement is that, contrary to Viking, the seismometers will be deployed via a robotic arm directly onto Mars’ surface and will be protected against temperature and wind by highly efficient thermal and wind shielding. Based on existing knowledge of Mars, it is reasonable to infer a moment magnitude detection threshold of Mw∼3 at 40∘ epicentral distance and a potential to detect several tens of quakes and about five impacts per year. In this paper, we first describe the science goals of the experiment and the rationale used to define its requirements. We then provide a detailed description of the hardware, from the sensors to the deployment system and associated performance, including transfer functions of the seismic sensors and temperature sensors. We conclude by describing the experiment ground segment, including data processing services, outreach and education networks and provide a description of the format to be used for future data distribution.
Publications 1 - 10 of 68