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27 records · Page 2Linked to original sources
USGS2021

Availability of subsurface water-ice resources in the northern mid-latitudes of Mars

Multiple nations and private entities are pushing to make landing humans on Mars a reality. The majority of proposed mission architectures envision ‘living off the land’ by leveraging Martian water-ice deposits for fuel production and other purposes. Fortunately for mission designers, water ice exists on Mars in plentiful volumes. The challenge is isolating accessible ice deposits within regions that optimize other preferred landing-site conditions. Here we present the first results of the Mars Subsurface Water Ice Mapping (SWIM) project, which has the aim of searching for buried ice resources across the mid-latitudes. Through the integration of orbital datasets in concert with new data-processing techniques, the SWIM project assesses the likelihood of ice by quantifying the consistency of multiple, independent data sources with the presence of ice. Concentrating our efforts across the majority of the northern hemisphere, our composite ice-consistency maps indicate that the broad plains of Arcadia and the extensive glacial networks across Deuteronilus Mensae match the greatest number of remote-sensing criteria for accessible ice-rich, subsurface material situated equatorwards of the contemporary ice-stability zone.

Nature Astronomy↗
USGS2021

A roadmap for planetary caves science and exploration

While researchers have pondered the possibility of extraterrestrial caves for more than 50 years, we have now entered the incipient phase of planetary caves exploration. Our knowledge of planetary caves varies from body to body. Earth represents the most advanced level of exploration, but many unanswered questions remain. Beyond Earth, identification of possible caves is most advanced for the Moon and Mars , with hundreds of documented candidate cave entrances and several proposed cave mission concepts. To date, the community has catalogued 2,660 SAPs on eight planetary bodies (excluding Earth) across our Solar System. Planetary caves science has the potential to significantly expand over the next decade. A potential roadmap for planetary cave research and exploration is discussed.

Nature Astronomy↗
USGS2024

A survey of the severity of mental health symptoms in the planetary science community

There is a growing recognition of a mental health crisis within the academic and research communities. Members of the planetary science community have called for healthier work environments to improve mental well-being. As a preliminary step towards improving workplace culture, we sought to determine whether the broader mental health crisis extends to planetary science and to assess the severity of anxiety, depressive and stress symptoms. Our 2022 mental health survey of the planetary science community suggests that the severity of anxiety and depressive symptoms in the community is greater than in the general US population. Furthermore, anxiety and depressive symptoms are more severe for graduate students and postdoctoral researchers than any other career stage. Comparing groups within planetary science, we found that anxiety, depressive and/or stress symptoms appear greater among marginalized groups, such as women, people of colour and members of the LGBTQ+ community. A mental health problem is impacting the planetary science community. Improving well-being will promote enhanced research quality and productivity.

Nature Astronomy↗
USGS2025

No magmatic driving force for Europan sea-floor volcanism

The internal ocean of Jupiter’s moon Europa is thought to be a prime candidate for hosting extraterrestrial life. Europa’s silicate interior may contribute to habitability via the generation of reactants through hydrothermal activity, serpentinization, or other geological processes occurring on or just below Europa’s seafloor. However, silicate melting is thought to occur at >100 km depth in Europa’s mantle and it is unknown if this magma is able to penetrate and travel through the moon’s likely thick, brittle lithosphere to erupt at the seafloor. Here we combine previous modeling approaches to Europan interior melt generation and lithospheric dyke transport to show that Europan seafloor volcanism is strongly inhibited by its lithosphere. The low stress state of the Europan interior hinders the ability of dykes to penetrate through the lithosphere. Should dykes form, they penetrate <5% of the 200–250 km-thick lithosphere. Low mantle melt fractions (3–5%) drive sluggish pore-space magma flow, leading to dyke influxes 10,000 times lower than that necessary for seafloor eruption. These results strongly suggest that models of Europan habitability reliant on present-day volcanism at its seafloor are implausible.

Nature Astronomy↗
USGS2002

Plumes, or plate tectonic processes?

Hotspots – large volcanic provinces – such as Iceland, Hawaii and Yellowstone, are almost universally assumed to come from plumes of hot mantle rising from deep within the Earth. At Iceland, perhaps the best-studied hotspot on Earth, this hypothesis is inconsistent with many first-order observations, such as the lack of high temperatures, a volcanic track or a seismic anomaly in the lower mantle. The great melt production there is explained better by enhanced fertility in the mantle where the mid-Atlantic spreading ridge crosses the Caledonian suture zone. The thick crust built by the excessive melt production encourages complex, unstable, leaky microplate tectonics, which provides positive feedback by enhancing volcanism further. Such a model explains Iceland as a natural consequence of relatively shallow processes related to plate tectonics, and accounts for all the first- and second-order geophysical, geological and geochemical observations at Iceland without special pleading or invoking coincidences.

Astronomy and Geophysics↗
USGS2005

Near-infrared (0.8-4.0 m) spectroscopy of mimas, enceladus, tethys, and rhea

Spectral measurements from the ground in the time leading up to the Cassini mission at Saturn provide important context for the interpretation of the forthcoming spacecraft data. Whereas ground-based observations cannot begin to approach the spatial scales Cassini will achieve, they do possess the benefits of better spectral resolution, a broader possible time baseline, and unique veiewing geometries not obtained by spacecraft (i.e., opposition). In this spirit, we present recent NIR reflectance spectra of four icy satellites of Saturn measured with the SpeX instrument at the IRTF. These measurements cover the range 0.8-4.0 m of both the leading and trailing sides of Tethys and the leading side of Rhea. The L -band region (2.8-4.0 m) offers new opportunities for searches of minor components on these objects. Additionally, these data include 0.8-2.5 m spectra of both the leading and trailing sides of Mimas and of the (mostly) trailing side of Enceladus. The spectrum of Enceladus shows activity near 2.25 m that we interpret as a possible signature of NH 3 ice. The presence of ammonia in the Saturn system is not unexpected, and may help explain the apparent recent geologic activity of Enceladus. Analysis of leading/trailing differences in H 2 O band depths, spectral slopes, and albedo imply a separate regime of surface modification for Mimas and Enceladus than for the more distant icy satellites (Tethys, Dione, Rhea). Aside from the potential NH 3 on Enceladus, no other minor constituents are detected in these icy surfaces.

Astronomy and Astrophysics↗
USGS2006

Observations in the Saturn system during approach and orbital insertion, with Cassini's visual and infrared mapping spectrometer (VIMS)

The Visual and Infrared Mapping Spectrometer observed Phoebe, Iapetus, Titan and Saturn's rings during Cassini's approach and orbital insertion. Phoebe's surface contains water ice, CO2, and ferrous iron. lapetus contains CO2 and organic materials. Titan's atmosphere shows methane fluorescence, and night-side atmospheric emission that may be CO2 and CH3D. As determined from cloud motions, the winds at altitude 25-30 km in the south polar region of Titan appear to be moving in a prograde direction at velocity ???1 m s-1. Circular albedo features on Titan's surface, seen at 2.02 ??m, may be palimpsests remaining from the rheological adjustment of ancient impact craters. As such, their long-term persistence is of special interest in view of the expected precipitation of liquids and solids from the atmosphere. Saturn's rings have changed little in their radial structure since the Voyager flybys in the early 1980s. Spectral absorption bands tentatively attributed to Fe2+ suggest that iron-bearing silicates are a source of contamination of the C ring and the Cassini Division. ?? ESO 2006.

Astronomy and Astrophysics↗
USGS1998

Digital structural mapping of Mars

Magmatic and tectonic activity have both contributed significantly to the surface geology of Mars. Digital structural mapping techniques have now been used to classify and date centers of tectonic activity in the western equatorial region. For example, our results show a center of tectonic activity at Valles Marineris, which may be associated with uplift caused by intrusion. Such evidence may help explain, in part, the development of the large troughs and associated outflow channels and chaotic terrain. We also find a local centre of tectonic activity near the source region of Warrego Valles. Here, we suggest that the valley system may have resulted largely from intrusive-related hydrothermal activity. We hope that this work, together with the current Mars Global Surveyor mission, will lead to a better understanding of the geological processes that shaped the Martian surface.

Astronomy and Geophysics↗