Chemical Composition of Icy Satellite Surfaces

Dalton, J. B.; Cruikshank, D. P.; Stephan, K.; McCord, T. B.; Coustenis, A.; Carlson, R. W.; Coradini, A.

doi:10.1007/978-1-4419-7439-6_5

Cited by 8 publications

(29 citation statements)

References 296 publications

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“…Hansen and McCord [] hypothesized a balance between thermal kinetic crystallization and radiolytic disruption that favors the presence of amorphous ice on Europa, crystalline ice on Callisto and both types on Ganymede. This distribution is in agreement with spectroscopic data collected by the NIMS experiment [ Hansen and McCord , ; Dalton et al, ]. It is worth noting, however, that amorphous ice is present only on the very surface, as below 1 mm depth the ice is predominantly in its crystalline state [ Dalton et al, ].…”

Section: An Overview On Terrestrial and Nonterrestrial Water Icesupporting

confidence: 87%

“…Figure illustrates that ice Ih could also transform to other phases as a function of pressure, although these transitions should occur at depths much larger than those expected to be sounded by RIME (about 9 km). On Jovian satellites water ice can also exist in an amorphous state, as inferred by Hansen and McCord [] and experimentally confirmed by spectroscopic data [ Hansen and McCord, ; Dalton et al, ]. The detailed evidence of the presence and nature of other chemical species has been obtained only recently, with the Galileo mission.…”

Section: Composition Of the Upper Layers Of The Icy Galilean Satellitesmentioning

confidence: 88%

“…Both terrestrial and extraterrestrial ices are often contaminated by chemical impurities (acids, bases, and salts) [ Dalton et al, ]; the effects of some of these impurities on the dielectric behavior of water ice are known due to their abundance in terrestrial ices (e.g., Na 2 SO 4 · 10H 2 O in sea ice). However, several ices formed by other volatiles such as hydrocarbons can only exist in the outer part of the solar system; they are very difficult to reproduce in the laboratory and their dielectric properties are usually unknown.…”

Section: Introductionmentioning

confidence: 99%

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Dielectric properties of Jovian satellite ice analogs for subsurface radar exploration: A review

Pettinelli

Cosciotti

Paolo

et al. 2015

Reviews of Geophysics

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The first European mission dedicated to the exploration of Jupiter and its icy moons (JUpiter ICy moons Explorer-JUICE) will be launched in 2022 and will reach its final destination in 2030. The main goals of this mission are to understand the internal structure of the icy crusts of three Galilean satellites (Europa, Ganymede, and Callisto) and, ultimately, to detect Europa's subsurface ocean, which is believed to be the closest to the surface among those hypothesized to exist on these moons. JUICE will be equipped with the 9 MHz subsurface-penetrating radar RIME (Radar for Icy Moon Exploration), which is designed to image the ice down to a depth of 9 km. Moreover, a parallel mission to Europa, which will host onboard REASON (Radar for Europa Assessment and Sounding: Ocean to Near-surface) equipped with 9MHz and 60MHz antennas, has been recently approved by NASA. The success of these experiments strongly relies on the accurate prediction of the radar performance and on the optimal processing and interpretation of radar echoes that, in turn, depend on the dielectric properties of the materials composing the icy satellite crusts. In the present review we report a complete range of potential ice types that may occur on these icy satellites to understand how they may affect the results of the proposed missions. First, we discuss the experimental results on pure and doped water ice in the framework of the Jaccard theory, highlighting the critical aspects in terms of a lack of standard laboratory procedures and inconsistency in data interpretation. We then describe the dielectric behavior of extraterrestrial ice analogs like hydrates and icy mixtures, carbon dioxide ice and ammonia ice. Building on this review, we have selected the most suitable data to compute dielectric attenuation, velocity, vertical resolution, and reflection coefficients for such icy moon environments, with the final goal being to estimate the potential capabilities of the radar missions as a function of the frequency and temperature ranges of interest for the subsurface sounders. We present the different subsurface scenarios and associated radar signal attenuation models that have been proposed so far to simulate the structure of the crust of Europa and discuss the physical and geological nature of various dielectric targets potentially detectable with RIME. Finally, we briefly highlight several unresolved issues that should be addressed, in near future, to improve our capability to produce realistic electromagnetic models of icy moon crusts. The present review is of interest for the geophysical exploration of all solar system bodies, including the Earth, where ice can be present at the surface or at relatively shallow depths.

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Section: An Overview On Terrestrial and Nonterrestrial Water Icesupporting

confidence: 87%

Section: Composition Of the Upper Layers Of The Icy Galilean Satellitesmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

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Dielectric properties of Jovian satellite ice analogs for subsurface radar exploration: A review

Pettinelli

Cosciotti

Paolo

et al. 2015

Reviews of Geophysics

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“…Nevertheless, these phase transitions should occur at depths larger than those expected to be sounded by the RIME and REASON radars, estimated to be in the range of a few kilometers to 10 km [ Pettinelli et al , ]. The presence of amorphous water ice is also inferred on the surface of the Jovian satellites [ Hansen and McCord , ; Dalton et al , ]: it is predominant on Europa's surface, in smaller proportion on Callisto's surface, and both phases are present on Ganymede's surface. However, Hansen and McCord [] suggest that the crystalline phase is predominant at a depth around 1 mm for the three satellites.…”

Section: Discussionmentioning

confidence: 99%

Characterization of the permittivity of controlled porous water ice-dust mixtures to support the radar exploration of icy bodies

Brouet

Neves

Sabouroux

et al. 2016

J. Geophys. Res. Planets

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The internal properties of porous and icy bodies in the solar system can be investigated by ground‐penetrating radars (GPRs), like the COmet Nucleus Sounding Experiment by Radiowave Transmission instrument on board the Rosetta spacecraft which has sounded the interior of the nucleus of comet 67P/Churyumov‐Gerasimenko. Accurate constraints on the permittivity of icy media are needed for the interpretation of the data. We report novel permittivity measurements performed on water ice samples and icy mixtures with porosities in the 31–91% range. The measurements have been performed between 50 MHz and 2 GHz with a coaxial cell on a total of 38 samples with a good reproducibility. We used controlled procedures to produce fine‐grained and coarse‐grained ice samples with a mean diameter of 4.5 μm and 67 μm, respectively, and to prepare icy mixtures. The JSC‐1A lunar regolith simulant was used as the dust component in the mixtures. The results are focused on the real‐part ε′ of the permittivity, which constrains the phase velocity of the radio waves in low‐loss media. The values of ε′ show a nondispersive behavior and are within the range of 1.1 to 2.7. They decrease with the increasing porosity Φ according to E(1 − Φ), with E equal to about 3.13 for pure water ice, and in the 3.8–7.5 range for ice‐dust mixtures with a dust‐to‐ice volumetric ratio in the 0.1–2.8 range, respectively. These measurements are also relevant for radiometers operating in the millimeter‐submillimeter domains, as suggested by the nondispersive behavior of the mixtures and of the pure components.

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“…This serves to illustrate the difficulty in obtaining the minimum energy conformations in such low‐symmetry structures. The present findings agree with the suggestion that the distorted water bands on Europa are due to H 3 O + species [ Dalton et al ., ]; hydronium ions have been identified by this study to occur in the structures of both SAO and SAHx. Although SAH, SAHx, and SAO each contain H 3 O + and H 2 O species, only SAHx contains the H 5 O 2 + species within its crystal structure.…”

Section: Discussionmentioning

confidence: 99%

A new material for the icy Galilean moons: The structure of sulfuric acid hexahydrate

2013

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[1] This study presents a newly identified water-rich crystalline form of sulfuric acid hydrate, H 2 SO 4 •6H 2 O, a hexahydrate. The method of formation of this material suggests that sulfuric acid hexahydrate (SAHx) could be an abundant material on the surface of Jupiter's Galilean ice moons, Europa, Ganymede, and Callisto. The structure of SAHx was determined by the combined use of synchrotron X-ray and neutron powder diffraction data. The structural arrangement of SAHx exhibits the same water layer topology that has been determined for sulfuric acid octahydrate (SAO), but differs in the stacking of this water layer and the interlayer species. SAHx is observed to form over a large range of solution compositions and displays stability over the temperature range 80 to 190 K.Citation: Maynard-Casely, H. E., K. S. Wallwork, and M. Avdeev (2013), A new material for the icy Galilean moons: The structure of sulfuric acid hexahydrate,

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Chemical Composition of Icy Satellite Surfaces

Cited by 8 publications

References 296 publications

Dielectric properties of Jovian satellite ice analogs for subsurface radar exploration: A review

Dielectric properties of Jovian satellite ice analogs for subsurface radar exploration: A review

Characterization of the permittivity of controlled porous water ice-dust mixtures to support the radar exploration of icy bodies

A new material for the icy Galilean moons: The structure of sulfuric acid hexahydrate

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