85 results on '"Michael Malaska"'
Search Results
2. The chemical composition of the Soi crater region on Titan
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Anezina Solomonidou, Michael Malaska, Rosaly Lopes, Athena Coustenis, Ashley Schoenfeld, Bernard Schmitt, Samuel Birch, and Alice Le Gall
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The Soi crater region, with the well-preserved Soi crater in its center, covers almost 10% of Titan’s surface. Schoenfeld et al. (2023) [1] mapped this region at 1:800,000 scale and produced a geomorphological map showing that the area consists of 22 distinct geomorphological units. The region includes the boundaries between the equatorial regions of Titan and the mid-latitudes and extends into the high northern latitudes (above 50o). We analyzed 262 different locations from several Visual and Infrared Mapping Spectrometer (VIMS) datacubes using a radiative transfer technique [2] and a mixing model [3], yielding compositional constraints on Titan’s optical surface layer and near-surface substrate compositional constraints using RADAR microwave emissivity. We have derived combinations of top surface materials between dark materials, tholin-like materials, water-ice, and methane. We found no evidence of CO2 and NH3 ice. We discuss our results in terms of origin and evolution theories.[1] Schoenfeld, A., et al. (2023), JGR-Planets 128, e2022JE007499; [2] Solomonidou, A., et al., (2020a), Icarus, 344, 113338; [3] Solomonidou, A., et al. (2020b), A&A, 641, A16.
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- 2023
3. Emergent biogeochemical risks from Arctic permafrost degradation
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Charles E. Miller, M. P. Waldrop, Juliana D'Andrilli, Arwyn Edwards, Kimberley R. Miner, Rachel Mackelprang, and Michael Malaska
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Arctic ,Environmental protection ,Environmental monitoring ,Environmental science ,Cryosphere ,Biogeochemistry ,Ecosystem ,Environmental Science (miscellaneous) ,Resilience (network) ,Permafrost ,geographic locations ,Social Sciences (miscellaneous) ,Natural (archaeology) - Abstract
The Arctic cryosphere is collapsing, posing overlapping environmental risks. In particular, thawing permafrost threatens to release biological, chemical and radioactive materials that have been sequestered for tens to hundreds of thousands of years. As these constituents re-enter the environment, they have the potential to disrupt ecosystem function, reduce the populations of unique Arctic wildlife and endanger human health. Here, we review the current state of the science to identify potential hazards currently frozen in Arctic permafrost. We also consider the cascading natural and anthropogenic processes that may compound the impacts of these risks, as it is unclear whether the highly adapted Arctic ecosystems have the resilience to withstand new stresses. We conclude by recommending research priorities to address these underappreciated risks. Thawing permafrost in the Arctic may release microorganisms, chemicals and nuclear waste that have been stored in frozen ground and by cold temperatures. This Review discusses the current state of potential hazards and their risks under warming to identify prospective threats to the Arctic.
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- 2021
4. Chemical composition analysis of Titan’s equatorial and midlatitude surface regions
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Anezina Solomonidou, Ashley Schoenfeld, Michael Malaska, Rosaly lopes, Athena Coustenis, Sam Birch, Alice Le Gall, and Bernard Schmitt
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The Cassini cameras and especially the Visual and infrared Mapping Spectrometer has provided a sequence of spectra showing the diversity of Titan’s surface spectrum from flybys performed during the 13 years of Cassini’s operation. The investigation of Titan’s surface chemical composition is of great importance for the understanding of the atmosphere-surface-interior system of the moon. The Soi crater region with the well-preserved Soi crater in its center, spans from Titan’s equatorial regions to high northern latitudes. This provides a rich diversity of landscapes, one that is also representative of the diversity encountered across Titan. We mapped this region at 1:800,000 scale using Cassini SAR and non-SAR data and produced a geomorphological map using the methodology presented by [1] and [2]. The VIMS coverage of the region allowed for detailed analysis of spectra of 262 different locations using a radiative transfer technique [3;4] and a mixing model [5;6], yielding compositional constraints on Titan’s optical surface layer. Additional constraints on composition on the near-surface substrate were obtained from microwave emissivity. We identified 22 geomorphological units, 3 of which were not previously described, and derived combinations of top surface materials between dark materials, tholin-like materials, water-ice, and methane. We found no evidence of CO2 and NH3 ice. We also observe empty lakes as far south as 40°N, which mark the most southern extent of Titan’s north polar lakes. We use the stratigraphic relations between our mapping units and the relation between the geomorphology and the composition of the surface layers to build hypotheses on the origin and evolution of the regional geology. [1] Malaska, M., et al. (2016), Icarus 270, 130; [2] Schoenfeld, A., et al. (2021), Icarus 366, 114516; [3] Solomonidou, A., et al. (2014), J. Geophys. Res. Planets, 119, 1729; [4] Solomonidou, A., et al. (2016), Icarus, 270, 85; [5] Solomonidou, A., et al. (2018), J. Geophys. Res. Planets, 123, 489; [6] Solomonidou, A., et al. (2020), A&A 641, A16.
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- 2022
5. Habitability of Hydrocarbon Worlds: Titan and Beyond
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Michael Malaska
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Introduction: Titan is an ocean world, an icy world, and an organic world. Recent models of the interior suggest that Titan’s subsurface ocean may be in contact with an organic-rich ice-rock core, potentially providing redox gradients, heavier elements, and organic building blocks critical for a habitable environment. Farther above, at the contact of the ice shell and ocean, Titan’s abundant surface organics could be delivered to the aqueous environment through processes such as potential convective cycles in the ice shell. Our work investigates the pathways for atmospheric organic products to be transported from the surface to the ocean/core and the potential for ocean/deep ice biosignatures and organisms to be transported to the shallow crust or surface for interrogation and discovery. Our major objectives are: (i) Determine the pathways for organic materials to be transported (and modified) from the atmosphere to surface and eventually to the subsurface ocean (the most likely habitable environment). (ii) Determine whether the physical and chemical processes in the ocean create stable, habitable environments. (iii) Determine what biosignatures would be produced if the ocean is inhabited. (iv) Determine how biosignatures can be transported from the ocean to the surface and atmosphere and be recognizable at the surface and atmosphere. Summary of Progress: Examining Titan’s atmosphere, we have coupled two atmospheric models that cover different altitudes provide a comprehensive integrated model of the entire atmosphere of Titan. On the observational side, analysis of ALMA data resulted in the first observation of the CH3D molecule at sub-millimeter wavelengths [1]. Analysis of NASA IRTF data resulted in the first detection of propadiene (CH2CCH2) in Titan’s atmosphere [2]. Spatial and seasonal changes in Titan’s gases from the final years of the Cassini mission were the subject of several papers, using data from ALMA [3] and CIRS [4, 5]. In order to understand how materials falling from the atmosphere are transported across the surface, we are developing a landscape evolution model, based on the DELIM code that is used for Mars. We have published the first global geomorphologic map of Titan [6], which will serve as a constraint for the landscape evolution model by showing how sedimentary and depositional materials are distributed over the surface. We obtained an updated estimate of the amount of organic materials on Titan, which is important as a constraint on the amount of chemical energy and building blocks available for potential life. To investigate the molecular pathways from surface to subsurface ocean, we have performed a series of numerical simulations on the effect of a clathrate layer capping Titan’s icy crust on the convection pattern in the stagnant lid regime [7]. In the investigation of habitats resulting from molecular transport, we have modeled the accretion of Titan to understand the effects of thermal evolution on the rocky interior, and to constrain the composition of volatiles exsolved from the interior and that may have migrated vertically to build up the ocean early in Titan’s history [8]. We have also published results of modeling water-hydrocarbon mixtures using the CRYOCHEM code, which now successfully allows chemical modeling of both the hydrocarbon-rich condensed fluid phases and the water-rich condensed fluid phases (and vapor phases, too) simultaneously [9]. Preliminary results for our investigation of ocean habitats led to new insights into the origin of methane and nitrogen (N2) on Titan by modeling D/H exchange between organics and water, as well as high pressure C-N-O-H fluid speciation in Titan’s rocky core [10]. Results suggest an important role for organic compounds in the geochemical evolution of Titan’s core, which may feed into the habitability of Titan’s ocean. A novel experimental high pressure culturing chamber has been developed to investigate high pressure biosignatures which could survive in Titan’s ocean [11]. Our aim is to demonstrate that earth organisms can survive and build biomass in Titan’s subsurface conditions. Acknowledgments: Part of this work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. This work was funded by NASA’s Astrobiology Institute grant NNN13D485T. References: [1] Thelen, A.E., et al. (2019) AJ, 157 (6), 219. [2] Lombardo, N.A., et al. (2019) ApJ Letters, 881: L3. [3] Cordiner, M.A., et al. (2019) AJ, 158:76. [4] Teanby, N. A. et al. (2019). GRL 46, 3079–3089. [5] Lombardo, N.A. et al. (2019): Icarus doi.org/10.1016/j.icarus.2018.08.027. [6] Lopes, R.M. (2020). Nature Astr., doi.org/10.1038/s41550-019-0917-6 [7] Kalousova K. and C. Sotin (2019) EPSC-DPS2019-288-1. [8] Neri, A., et al. (2020) Earth Planet. Sci. Lett., 530, 115920. [9] Tan, S. et al. (2019): ACS Earth 3, 11, 2569–258. [10] Miller, K.A. et al., (2019), Astrophys. J. 871, 59. [11] Russo, D., et al. (2021) AGU Fall Meeting.
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- 2022
6. Sampling Accelerated Micron Scale Ice Particles with a Quadrupole Ion Trap Mass Spectrometer
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Sarah E. Waller, J. Simcic, F. Maiwald, Morgan L. Cable, Michael Malaska, S. M. Madzunkov, Anton Belousov, Dragan Nikolic, Robert E. Continetti, and Morgan E. C. Miller
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Chemistry ,Instrumentation ,010401 analytical chemistry ,010402 general chemistry ,Mass spectrometry ,01 natural sciences ,0104 chemical sciences ,Computational physics ,Plume ,Planetary science ,Structural Biology ,Saturn ,Ion trap ,Quadrupole ion trap ,Enceladus ,Spectroscopy - Abstract
The Enceladus plume is a target of astrobiological interest in planetary science since it may carry signs of extraterrestrial life entrapped in ice grains formed from the subsurface ocean of this moon of Saturn. Fly-by mission concepts have been proposed to perform close investigations of the plume, including detailed in situ measurements of chemical composition with a new generation of mass spectrometer instrumentation. Such a scenario involves high-velocity collisions (typically around 5 km/s or higher) of the instrument with the encountered ice grains. Postimpact processes may include molecular fragmentation, impact ionization, and various subsequent chemical reactions that could alter the original material prior to analysis. In order to simulate Enceladus plume fly through conditions, we are developing an ice grain accelerator and have coupled it to the quadrupole ion trap mass spectrometer (QITMS) developed for flight applications. Our experimental setup enables the creation and acceleration of ice particles with well-defined size, charge, and velocity, which are subsequently directed into the QITMS, where they impact the surface of the mass analyzer and the analysis of postimpact, volatilized molecules takes place. In this work, we performed mass spectral analysis of ice grains of ca. 1.3 μm in diameter, accelerated and impacted at velocities up to 1000 m/s, with an upgrade of the accelerator in progress that will enable velocities up to 5000 m/s. We report the first observations of ice grain impacts measured by the QITMS, which were recorded as brief increases in the abundance of water molecules detected within the instrument.
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- 2021
7. FT-IR MEASUREMENTS OF CROSSSECTIONS FOR TRANS-2-BUTENE IN THE 7-15 μM REGION AT 160-297 K FOR TITAN’S ATMOSPHERE
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Keeyoon Sung, Conor Nixon, Rosaly Lopes, Michael Malaska, and Brendan Steffens
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- 2022
8. Anisotropic thermal expansion of the acetylene–ammonia co-crystal under Titan's conditions
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Helen E. Maynard-Casely, Mathieu Choukroun, T. H. Vu, Michael Malaska, Morgan L. Cable, and Robert Hodyss
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Diffraction ,010504 meteorology & atmospheric sciences ,Intermolecular force ,Atmospheric temperature range ,01 natural sciences ,General Biochemistry, Genetics and Molecular Biology ,Thermal expansion ,Crystallography ,symbols.namesake ,0103 physical sciences ,symbols ,Orthorhombic crystal system ,Titan (rocket family) ,Anisotropy ,010303 astronomy & astrophysics ,Ene reaction ,0105 earth and related environmental sciences - Abstract
Acetylene and ammonia are known to form a stable orthorhombic co-crystal under the surface conditions of Saturn's moon Titan (1.5 bar = 150 kPa, 94 K). Such a material represents a potential new class of organic minerals that could play an important role in Titan's geology. In this work, the thermal expansion of this co-crystalline system has been derived from in situ powder X-ray diffraction data obtained between 85 and 120 K. The results indicate significant anisotropy, with the majority of the expansion occurring along the c axis (∼2% over the temperature range of interest). Rietveld refinements reveal little change to the structure compared with that previously reported by Boese, Bläser & Jansen [J. Am. Chem. Soc. (2009), 131, 2104–2106]. The expansion is consistent with the alignment of C—H...N interactions along the chains in the a and b axes, and weak intermolecular bonding in the structural layers along the c axis.
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- 2020
9. Subsurface In Situ Detection of Microbes and Diverse Organic Matter Hotspots in the Greenland Ice Sheet
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Gale Paulsen, E. Eshelman, John C. Priscu, Rohit Bhartia, Kenneth Manatt, Michael Malaska, William Abbey, Kris Zacny, J. Palmowski, B. Mellerowicz, and Juliana D'Andrilli
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In situ ,chemistry.chemical_classification ,geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Spectrometer ,Firn ,Mineralogy ,Greenland ice sheet ,Glacier ,01 natural sciences ,Agricultural and Biological Sciences (miscellaneous) ,symbols.namesake ,chemistry ,Space and Planetary Science ,0103 physical sciences ,symbols ,Organic matter ,Titan (rocket family) ,Enceladus ,010303 astronomy & astrophysics ,Geology ,0105 earth and related environmental sciences - Abstract
We used a deep-ultraviolet fluorescence mapping spectrometer, coupled to a drill system, to scan from the surface to 105 m depth into the Greenland ice sheet. The scan included firn and glacial ice...
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- 2020
10. The Soi crater region on Titan: Detailed geomorphological and compositional maps
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Anezina Solomonidou, Ashley Schoenfeld, Rosaly Lopes, Michael Malaska, Athena Coustenis, and Bernard Schmitt
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The Soi crater region, an extensive region covering almost 10% of Titan’s surface, has the Soi crater in its middle, which is a relatively well-preserved crater on Titan. This region includes the boundaries between the equatorial regions of Titan and the mid-latitudes, and extends into the high northern latitudes (above 50o). All these three Titan latitudes are dominated by different types of geomorphological units, such as dunes, mountains, and lakes, and are governed by different geological processes (such as lacustrine, aeolian and fluvial). An additional important and unique characteristic of the Soi crater region is that it includes 59 empty lakes, and the extent of these features reaches as far south as 40oN. We mapped this region at 1:800,000 scale and produced the first detailed geomorphological map of the region using the same methodology as presented by [1;2] and Schoenfeld et al. [3]. We included non-SAR (Synthetic Aperture Radar) data such as radiometry, ISS, and VIMS data in order to analyze vast areas not observed by SAR. We performed detailed VIMS analysis of hundreds of distinct regions for all geomorphological units with a radiative transfer technique [4] and a mixing model [5], to infer constraints on the composition. In our results, we introduce new geomorphological units, which were not seen in previous mapping of large Titan regions such as the Afekan and South Belet, and report the extensive presence of the scalloped plains units and their possible origin. A total of 10 craters, including Soi, are identified in this region, which are older than the plains and dune units. The radiative transfer analysis from VIMS showed that the major constituents covering the Soi crater region are compatible with water ice and organic alkane, alkene and alkyl-like stretch materials. We discuss our results in terms of origin and evolution theories.[1] Malaska, M., et al. (2016), Icarus 270, 130; [2] Malaska, M., et al. (2020), Icarus, 344, 113764. [3] Schoenfeld, A., et al. (2021), Icarus 366, 114516. [4] Solomonidou, A., et al. (2020a), Icarus, 344, 113338; [5] Solomonidou, A., et al. (2020b), A&A 641, A16.
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- 2022
11. Ganymede paterae: a priority target for JUICE
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Anezina Solomonidou, Michael Malaska, Katrin Stephan, Krista Soderlund, Martin Valenti, Alice Lucchetti, Klara Kalousova, and Rosaly Lopes
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Juice ,Ganymede ,paterae - Abstract
The JUpiter ICy moons Explorer (JUICE), the first large-class of the European Space Agency (ESA), is planned to launch in 2023, and one of its main goals is to make detailed observations of Jupiter’s moon Ganymede. The mission will investigate the past and/or recent cryovolcanic and tectonic activity of the moon and the exchange processes with the subsurface and possibly with the ocean. Recently, the science team defined “potential cryovolcanic regions” as a category of high interest for observation by JUICE (Stephan et al., 2021). For preparation of the scientific return of the mission, it is important to study in detail the regions that are considered to be good candidates for past/present activity. Light material areas on Ganymede imaged by Voyager have been suggested to represent dark terrain resurfaced by cryovolcanic flows (e.g., Parmentier et al., 1982), while the dark terrain’s speculated cryovolcanic origin was later disputed based on higher-resolution images of the Galileo mission. Additional Galileo data showed the significant role of tectonism in the formation of the light material areas, while the role of cryovolcanism remained inconclusive. Currently, small, isolated depressions called ‘paterae’, are the best candidate regions for cryovolcanic activity on Ganymede and suggested to be potential caldera-like cryovolcanic source vents (e.g., Spaun et al., 2001). Their nature has been interpreted as “possible cryovolcanic source vents for extrusion of clean icy material to form light material units” (Collins et al., 2013), and their small size is consistent with a cryovolcanic origin that operates on a local scale. The high-resolution JUICE camera, JANUS, in combination with other remote sensing instruments, is expected to resolve many of the mysteries concerning cryovolcanism on Ganymede and the origin of the moon’s varied geologic features. The “potential cryovolcanic regions” identified by the JUICE team includes 19 out of 30 paterae mapped by Collins et al., (2013) using Voyager and Galileo images. In this study, with the aim to enhance the preparation of the JUICE mission and its science return, we present: a thorough view of all 19 paterae regions; a detailed geomorphological characterization and comparison between the Ganymede paterae with paterae from other planetary bodies; and a spectral assessment using Galileo NIMS data.
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- 2022
12. Properties and Behavior of the Acetonitrile–Acetylene Co-Crystal under Titan Surface Conditions
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Robert Hodyss, Mathieu Choukroun, Tuan H. Vu, Helen E. Maynard-Casely, Morgan L. Cable, and Michael Malaska
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chemistry.chemical_classification ,Atmospheric Science ,Materials science ,Nitrile ,Photochemistry ,Surface conditions ,Organic molecules ,Aerosol ,chemistry.chemical_compound ,symbols.namesake ,Hydrocarbon ,chemistry ,Acetylene ,Space and Planetary Science ,Geochemistry and Petrology ,symbols ,Acetonitrile ,Titan (rocket family) - Abstract
Titan, the largest satellite of Saturn, possesses a complex photochemical cycle producing a broad inventory of organic molecules in its thick atmosphere and on its surface. Two of the most common m...
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- 2020
13. A Co-Crystal between Acetylene and Butane: A Potentially Ubiquitous Molecular Mineral on Titan
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Robert Hodyss, Michael Malaska, Helen E. Maynard-Casely, Tuan H. Vu, Mathieu Choukroun, and Morgan L. Cable
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Alkane ,chemistry.chemical_classification ,Atmospheric Science ,Chemistry ,Butane ,Photochemistry ,Methane ,chemistry.chemical_compound ,symbols.namesake ,Hydrocarbon ,Acetylene ,Space and Planetary Science ,Geochemistry and Petrology ,symbols ,Benzene ,Titan (rocket family) ,Dissolution - Abstract
Titan hosts a complex chemical engine producing a rich inventory of organic molecules in its thick atmosphere and on its surface. Some of these organics may be deposited in the liquid hydrocarbon lakes in the polar regions and form evaporite features when the lakes dry out as part of Titan’s methane/ethane cycle that is analogous to Earth’s hydrologic cycle. Modeling suggests that acetylene and butane would be the main components of such evaporite deposits. We have previously demonstrated that some organic molecules (such as benzene and ethane) readily form co-crystals in Titan-relevant conditions. We report here Raman spectroscopic evidence for a new co-crystal between acetylene and butane, which could be the most common organic co-crystal discovered so far of direct relevance to Titan’s surface. Intermolecular interactions such as those in the acetylene-butane co-crystal could modify the kinetics and equilibria of various processes (dissolution, reprecipitation, etc.) and therefore may play a key role i...
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- 2019
14. The Role of Seasonal Sediment Transport and Sintering in Shaping Titan's Landscapes: A Hypothesis
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Mathieu Lapotre, Morgan Cable, and Michael Malaska
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Geophysics ,General Earth and Planetary Sciences - Abstract
Titan is a sedimentary world, with lakes, rivers, canyons, fans, dissected plateaux, and sand dunes. Sediments on Saturn's moon are thought to largely consist of mechanically weak organic grains, prone to rapid abrasion into dust. Yet, Titan's equatorial dunes have likely been active for 10s-100s kyr. Sustaining Titan's dunes over geologic timescales requires a mechanism that produces sand-sized particles at equatorial latitudes. We explore the hypothesis that a combination of abrasion, when grains are transported by winds or methane rivers, and sintering, when they are at rest, could produce sand grains that maintain an equilibrium size. Our model demonstrates that seasonal sediment transport may produce sand under Titan's surface conditions and could explain the latitudinal zonation of Titan's landscapes. Our findings support the hypothesis of global, source-to-sink sedimentary pathways on Titan, driven by seasons, and mediated by episodic abrasion and sintering of organic sand by rivers and winds.
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- 2021
15. Modeling the formation of Menrva impact crater on Titan: Implications for habitability
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Brandon C. Johnson, Michael Malaska, Elizabeth A. Silber, E. E. Bjonnes, R. M. C. Lopes, Steve Vance, A. Solomonidou, Jason M. Soderblom, Christophe Sotin, and A. P. Crósta
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geography ,geography.geographical_feature_category ,Bedrock ,Astronomy and Astrophysics ,Context (language use) ,Astrobiology ,Atmosphere ,symbols.namesake ,Impact crater ,Space and Planetary Science ,Hypervelocity ,symbols ,Erosion ,Titan (rocket family) ,Subsurface flow ,Geology - Abstract
Titan is unique in the solar system: it is an ocean world, an icy world, an organic world, and has a dense atmosphere. It is a geologically active world as well, with ongoing exogenic processes, such as rainfall, sediment transportation and deposition, erosion, and possible endogenic processes, such as tectonism and cryovolcanism. This combination of an organic and an ocean world makes Titan a prime target for astrobiological research, as biosignatures may be present in its surface, in impact melt deposits and in cryovolcanic flows, as well as in deep ice and water ocean underneath the outer ice shell. Impact craters are important sites in this context, as they may have allowed an exchange of materials between Titan's layers, in particular between the surface, composed of organic sediments over icy bedrock, and the subsurface ocean. It is also possible that impacts may have favored the advance of prebiotic chemical reactions themselves, by providing thermal energy that would allow these reactions to proceed. To investigate possible exchange pathways between the subsurface water ocean and the organic-rich surface, we modeled the formation of the largest crater on Titan, Menrva, with a diameter of ca. 425 km. The premise is that, given a large enough impact event, the resulting crater could breach into Titan's ice shell and reach the subsurface ocean, creating pathways connecting the surface and the ocean. Materials from the deep subsurface ocean, including salts and potential biosignatures of putative subsurface biota, could be transported to the surface. Likewise, atmospherically derived organic surface materials could be directly inserted into the ocean, where they could undergo aqueous hydrolysis to form potential astrobiological building blocks, such as amino acids. To study the formation of a Menrva-like impact crater, we staged numerical simulations using the iSALE-2D shock physics code. We varied assumed ice shell thickness from 50 to 125 km and assumed thermal structure over a range consistent with geophysical data. We analyze the implications and potential contributions of impact cratering as a process that can facilitate the exchange of surface organics with liquid water. Our findings indicate that melt and partial melt of ice took place in the central zone, reaching ca. 65 km depth and ca. 60 km away from the center of the structure. Furthermore, a volume of ca. 102 km3 of ocean water could be traced to depths as shallow as 10 km. These results highlight the potential for a significant exchange of materials from the surface (organics and ice) and the subsurface (water ocean), particularly in the crater's central area. Our studies suggest that large hypervelocity impacts are a viable and likely key mechanism to create pathways between the underground water ocean and Titan's organic-rich surface layer and atmosphere.
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- 2021
16. Habitability Models for Astrobiology
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Alfonso F. Davila, Juan F. Salazar, Guillermo Nery, Jorge I. Zuluaga, Nicole J. Torres-Santiago, Abel Méndez, E. Nathan, Edgard G. Rivera-Valentín, Frances Rivera-Hernandez, Marta Filipa Simões, Ramses M. Ramirez, Noam R. Izenberg, Grizelle González, Corine Brown, Justin Filiberto, Jesús Martínez-Frías, Howard Chen, Marcos Jusino-Maldonado, André Antunes, Dirk Schulze-Makuch, Ludmila Carone, Jacob Haqq-Misra, Tana E. Wood, Kevin N. Ortiz Ceballos, Madhu Kashyap Jagadeesh, René Heller, Dimitra Atri, Paul K. Byrne, Christopher P. McKay, Priscilla Nowajewski-Barra, Humberto Itic Carvajal Chitty, David C. Catling, Kennda Lynch, and Michael Malaska
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010504 meteorology & atmospheric sciences ,Gradual transition ,Extraterrestrial Environment ,Earth, Planet ,FOS: Physical sciences ,Planets ,01 natural sciences ,Quantitative Biology - Quantitative Methods ,Astrobiology ,0103 physical sciences ,Exobiology ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,010303 astronomy & astrophysics ,Quantitative Methods (q-bio.QM) ,0105 earth and related environmental sciences ,Earth and Planetary Astrophysics (astro-ph.EP) ,Planetary habitability ,Habitability ,Agricultural and Biological Sciences (miscellaneous) ,Exoplanet ,Habitat suitability ,Key factors ,Space and Planetary Science ,FOS: Biological sciences ,Environmental science ,Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Earth and Planetary Astrophysics - Abstract
Habitability has been generally defined as the capability of an environment to support life. Ecologists have been using Habitat Suitability Models (HSMs) for more than four decades to study the habitability of Earth from local to global scales. Astrobiologists have been proposing different habitability models for some time, with little integration and consistency among them, being different in function to those used by ecologists. Habitability models are not only used to determine if environments are habitable or not, but they also are used to characterize what key factors are responsible for the gradual transition from low to high habitability states. Here we review and compare some of the different models used by ecologists and astrobiologists and suggest how they could be integrated into new habitability standards. Such standards will help to improve the comparison and characterization of potentially habitable environments, prioritize target selections, and study correlations between habitability and biosignatures. Habitability models are the foundation of planetary habitability science and the synergy between ecologists and astrobiologists is necessary to expand our understanding of the habitability of Earth, the Solar System, and extrasolar planets., Published in Astrobiology, 21(8). arXiv admin note: substantial text overlap with arXiv:2007.05491
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- 2021
17. Compositional mapping of Titan’s surface using Cassini VIMS and RADAR data
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Christos Matsoukas, Athena Coustenis, Charles Elachi, Rosaly M. C. Lopes, Yannis Markonis, Stephen D. Wall, Bernard Schmidtt, Ashley Schoenfeld, Kenneth J. Lawrence, Alice Le Gall, A. Solomonidou, Christophe Sotin, and Michael Malaska
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Surface (mathematics) ,symbols.namesake ,13. Climate action ,law ,symbols ,15. Life on land ,Radar ,Titan (rocket family) ,Geology ,Remote sensing ,law.invention - Abstract
The investigation of Titan’s surface chemical composition is of great importance for the understanding of the atmosphere-surface-interior system of the moon. The Cassini cameras and especially the Visual and infrared Mapping Spectrometer has provided a sequence of spectra showing the diversity of Titan’s surface spectrum from flybys performed during the 13 years of Cassini’s operation. In the 0.8-5.2 μm range, this spectro-imaging data showed that the surface consists of a multivariable geological terrain hosting complex geological processes. The data from the seven narrow methane spectral “windows” centered at 0.93, 1.08, 1.27, 1.59, 2.03, 2.8 and 5 μm provide some information on the lower atmospheric context and the surface parameters. Nevertheless, atmospheric scattering and absorption need to be clearly evaluated before we can extract the surface properties. In various studies (Solomonidou et al., 2014; 2016; 2018; 2019; 2020a, 2020b; Lopes et al., 2016; Malaska et al., 2016; 2020), we used radiative transfer modeling in order to evaluate the atmospheric scattering and absorption and securely extract the surface albedo of multiple Titan areas including the major geomorphological units. We also investigated the morphological and microwave characteristics of these features using Cassini RADAR data in their SAR and radiometry mode. Here, we present a global map for Titan’s surface showing the chemical composition constraints for the various units. The results show that Titan’s surface composition, at the depths detected by VIMS, has significant latitudinal dependence, with its equator being dominated by organic materials from the atmosphere and a very dark unknown material, while higher latitudes contain more water ice. The albedo differences and similarities among the various geomorphological units give insights on the geological processes affecting Titan’s surface and, by implication, its interior. We discuss our results in terms of origin and evolution theories. References: [1] Solomonidou, A., et al. (2014), J. Geophys. Res. Planets, 119, 1729; [2] Solomonidou, A., et al. (2016), Icarus, 270, 85; [3] Solomonidou, A., et al. (2018), J. Geophys. Res. Planets, 123, 489; [4] Solomonidou, A., et al. (2020a), Icarus, 344, 113338; [5] Solomonidou, A., et al. (2020b), A&A 641, A16; [6] Lopes, R., et al. (2016) Icarus, 270, 162; [7] Malaska, M., et al. (2016), Icarus 270, 130; [8] Malaska, M., et al. (2020), Icarus, 344, 113764. Acknowledgements: This work was conducted at the California Institute of Technology (Caltech) under contract with NASA. Y.M. and A.S. (partly) was supported by the Czech Science Foundation (grant no. 20-27624Y). ©2021 California Institute of Technology. Government sponsorship acknowledged.
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- 2021
18. A roadmap for planetary caves science and exploration
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Cansu Demirel-Floyd, J. W. Ashley, Amos Frumkin, Armando Azua-Bustos, Norbert Schorghofer, Leroy Chiao, William Whittaker, Jo De Waele, Richard Leveille, Jennifer E.C. Scully, Penelope J. Boston, Cynthia B. Phillips, Ali-akbar Agha-mohammadi, Michael Malaska, Matteo Massironi, Uland Wong, Pablo de León, Bogdan P. Onac, Debra Buczkowski, Francesco Sauro, Kavya K. Manyapu, Heather Jones, Haley M. Sapers, R. V. Wagner, P. B. Buhler, J. Judson Wynne, Kyle Uckert, Gary L. Harris, John DeDecker, Charity M. Phillips-Lander, Glen E. Cushing, Scott Parazynski, L. Kerber, Dirk Schulze-Makuch, Kaj E. Williams, E. Calvin Alexander, Erin Leonard, Ana Z. Miller, Timothy N. Titus, John E. Mylroie, Alberto G. Fairén, Thomas H. Prettyman, Wynne, Judson, Malaska, Michael J., Azua-Bustos A., León, Pablo G. de, Waele, J. de, Massironi, M., Miller, A. Z., Onac, Bogdan P., Prettyman, Thomas H., Sauro, Francesco, Uckert, Kyle, Cushing, Glen E., Fairén, Alberto G., Frumkin, Amos, Kerber, Laura H., Parazynski, Scott E., Phillips-Lander, Charity M., Schulze-Makuch, Dirk, Wagner, Robert V., Williams, Kaj E., Wynne, Judson [0000-0003-0408-0629], Malaska, Michael J. [0000-0003-0064-5258], Azua-Bustos A. [0000-0002-6590-4145], León, Pablo G. de [0000-0002-6046-8700], Waele, J. de [0000-0001-5325-5208], Massironi, M. [0000-0002-7757-8818], Miller, A. Z. [0000-0002-0553-8470], Onac, Bogdan P. [0000-0003-2332-6858], Prettyman, Thomas H. [0000-0003-0072-2831], Sauro, Francesco [0000-0002-1878-0362], Uckert, Kyle [0000-0002-0859-5526], Titus, Timothy N., Wynne, J. Judson, Agha-Mohammadi, Ali-akbar, Buhler, Peter B., Alexander, E. Calvin, Ashley, James W., Azua-Bustos, Armando, Boston, Penelope J., Buczkowski, Debra L., Chiao, Leroy, DeDecker, John, de León, Pablo, Demirel-Floyd, Cansu, De Waele, Jo, Frumkin, Amo, Harris, Gary L., Jones, Heather, Leonard, Erin J., Léveillé, Richard J., Manyapu, Kavya, Massironi, Matteo, Miller, Ana Z., Mylroie, John E., Parazynski, Scott, Phillips, Cynthia B., Sapers, Haley M., Schorghofer, Norbert, Scully, Jennifer E., Whittaker, William L., and Wong, Uland Y.
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Planetary caves, exploration, methods ,geography ,geography.geographical_feature_category ,Cave ,InformationSystems_INFORMATIONINTERFACESANDPRESENTATION(e.g.,HCI) ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,Astronomy and Astrophysics ,GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries) ,GeneralLiterature_MISCELLANEOUS ,Geology ,ComputingMethodologies_COMPUTERGRAPHICS ,Astrobiology - Abstract
2 páginas.- 1 figura.- 16 referencias, To the Editor — 2021 is the International Year of Caves and Karst. To honour this occasion, we wish to emphasize the vast potential embodied in planetary subsurfaces. 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....
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- 2021
19. Geomorphological map of the South Belet Region of Titan
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T. Verlander, Alexander Hayes, Paul Corlies, Samuel Birch, David A. Williams, Meghan Florence, Stéphane Le Mouélic, Ashley Schoenfeld, Elizabeth P. Turtle, Alice Le Gall, Michael Malaska, Rosaly M. C. Lopes, Michael A. Janssen, A. Solomonidou, Department of Earth, Planetary and Space Sciences [Los Angeles] (EPSS), University of California [Los Angeles] (UCLA), University of California-University of California, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), California Institute of Technology (CALTECH), Faculty of Environmental Sciences [Prague], Czech University of Life Sciences Prague (CZU), School of Earth and Space Exploration [Tempe] (SESE), Arizona State University [Tempe] (ASU), Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), Department of Astronomy [Ithaca], Cornell University [New York], PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), School of Civil Engineering and Environmental Science [Norman] (CEES), and University of Oklahoma (OU)
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010504 meteorology & atmospheric sciences ,Terrain ,01 natural sciences ,Latitude ,symbols.namesake ,Impact crater ,0103 physical sciences ,010303 astronomy & astrophysics ,Geomorphology ,0105 earth and related environmental sciences ,geography ,geography.geographical_feature_category ,Alluvial fan ,Astronomy and Astrophysics ,Crust ,15. Life on land ,Alluvial plain ,Geologic processes ,13. Climate action ,Space and Planetary Science ,[SDU]Sciences of the Universe [physics] ,Titan surface ,symbols ,Longitude ,Titan (rocket family) ,Titan ,Geology - Abstract
International audience; We mapped in detail Titan's South Belet region which spans from longitude 60°E to 120°E and from latitude 60°S to 0°, encompassing both equatorial and southern mid-latitude regions. We used Cassini RADAR in its Synthetic Aperture Radar (SAR) mode data as our basemap, which covers 31.8% of the region, supplemented with data from the RADAR's radiometry mode, the Imagining Science Subsystem (ISS), the Visual and Infrared Mapping Spectrometer (VIMS), and topographic data. This mapping work is a continuation of the detailed global mapping effort introduced in Malaska et al. (2016a) and continued in Lopes et al. (2020). We followed the mapping procedure described in Malaska et al. (2016a) for the Afekan Crater region and identified four major terrain classes in South Belet: craters, hummocky/mountainous, plains, and dunes. Each terrain class was subdivided into terrain units by characteristic morphology, including border shape, texture, general appearance, and radar backscatter. There are two terrain units that were not included in previous studies but were identified in our mapping of South Belet: “bright alluvial plains” and “pitted hummocky”. Similar to the Afekan Crater region, we find that plains dominate the surface make-up of South Belet, comprising ~47% of the mapped area. Unlike Afekan, the areal extent of the dunes closely rivals the dominance of plains, making up 43% of the mapped area. The next most widespread unit by area in the region following the dunes are the mountains/hummocky terrains (10%), and finally, crater terrains (0.01%). The introduction of two new units, “bright alluvial plains” and “pitted hummocky”, are necessary to capture the full range of morphologies seen in South Belet and expands our understanding of processes typical of Titan's equatorial and mid-latitude regions. For example, the presence of alluvial fans indicates a period in Titan's past where discharges and slopes were such that sediment could be mobilized and deposited. Similarly, the pits associated with the “pitted hummocky” may represent an important erosional feature, with implications for the removal of volatiles from Titan's crust. However, analysis of our geomorphological mapping results suggests the geology of South Belet is consistent with the narrative of organics dominating the equatorial and mid-latitudes. This is similar to the conclusion we arrived at through our mapping and analysis of the Afekan region. Lastly, the applicability of the terrain units from our mapping of the Afekan region, which bears a similar latitude but in the northern hemisphere, to our mapping of South Belet suggests latitudinal symmetry in Titan's surface processes and their evolution.
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- 2021
20. The Enceladus Orbilander Mission Concept: Balancing Return and Resources in the Search for Life
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Samuel P. Kounaves, Christopher R. Glein, Christopher E. Bradburne, Marc Neveu, Morgan L. Cable, Jorge I. Nunez, Chris German, Jean Pierre Paul de Vera, Christopher P. McKay, G. Wesley Patterson, Alfonso F. Davila, Jennifer L. Eigenbrode, John Robert Brucato, Michael Malaska, C. C. Porco, Julie A. Huber, Robert E. Gold, Jason D. Hofgartner, Frank Postberg, Peter J. Greenauer, Linder J. Spilker, Johnathan I. Lunine, J. Hunter Waite, Karen Kirby, Shannon MacKenzie, Charity M. Phillips-Lander, and Kathleen L. Craft
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010504 meteorology & atmospheric sciences ,Planetare Labore ,Astronomy and Astrophysics ,01 natural sciences ,Astrobiology ,Geophysics ,Planetary science ,Enceladus Orbilander Mission Concept ,13. Climate action ,Space and Planetary Science ,Saturn ,0103 physical sciences ,Earth and Planetary Sciences (miscellaneous) ,Orbit (dynamics) ,Enceladus ,010303 astronomy & astrophysics ,Geology ,0105 earth and related environmental sciences - Abstract
Enceladus’s long-lived plume of ice grains and water vapor makes accessing oceanic material readily achievable from orbit (around Saturn or Enceladus) and from the moon’s surface. In preparation for the National Academies of Sciences, Engineering and Medicine 2023–2032 Planetary Science and Astrobiology Decadal Survey, we investigated four architectures capable of collecting and analyzing plume material from orbit and/or on the surface to address the most pressing questions at Enceladus: Is the subsurface ocean inhabited? Why, or why not? Trades specific to these four architectures were studied to allow an evaluation of the science return with respect to investment. The team found that Orbilander, a mission concept that would first orbit and then land on Enceladus, represented the best balance. Orbilander was thus studied at a higher fidelity, including a more detailed science operations plan during both orbital and landed phases, landing site characterization and selection analyses, and landing procedures. The Orbilander mission concept demonstrates that scientifically compelling but resource-conscious Flagship-class missions can be executed in the next decade to search for life at Enceladus.
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- 2021
21. Raised Rims Around Titan's Sharp‐Edged Depressions
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Rosaly M. C. Lopes, Oliver L. White, Alexander G. Hayes, Jonathan I. Lunine, Samuel Birch, Michael Malaska, Jason D. Hofgartner, S. D. Wall, and Valerio Poggiali
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symbols.namesake ,Geophysics ,symbols ,General Earth and Planetary Sciences ,Titan (rocket family) ,Geology ,Astrobiology - Published
- 2019
22. WATSON:In SituOrganic Detection in Subsurface Ice Using Deep-UV Fluorescence Spectroscopy
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Luther W. Beegle, John C. Priscu, Michael Malaska, Kenneth Manatt, Greg Wanger, E. Eshelman, Ivria J. Doloboff, William Abbey, M. Willis, and Rohit Bhartia
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In situ ,Space and Planetary Science ,Chemistry ,Cryosphere ,Spectroscopy ,Enceladus ,Agricultural and Biological Sciences (miscellaneous) ,Fluorescence ,Life detection ,Astrobiology - Abstract
Terrestrial icy environments have been found to preserve organic material and contain habitable niches for microbial life. The cryosphere of other planetary bodies may therefore also serve...
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- 2019
23. The next frontier for planetary and human exploration
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Christopher S. Edwards, Vlada Stamenkovic, Duane P. Moser, Darmindra D. Arumugam, Brian H. Wilcox, Ana-Catalina Plesa, Woodward W. Fischer, Giuseppe Etiope, John F. Mustard, Magdalena R. Osburn, Ryan Woolley, P. Boston, Jennifer G. Blank, John A. Baross, Nathaniel E. Putzig, I. Cooper, B. Menez, Atsuko Kobayashi, Michael Tuite, B. Sherwood Lollar, Victoria J. Orphan, Kris Zacny, Joseph L. Kirschvink, Luther W. Beegle, Rohit Bhartia, J. D. Tarnas, Tom Komarek, William B. Brinckerhoff, Pietro Baglioni, Lewis M. Ward, Daniel P. Glavin, Michael Malaska, Mariko Burgin, Haley M. Sapers, Michael J. Russell, Michael A. Mischna, Fumio Inagaki, Velibor Cormarkovic, Robert E. Grimm, R. M. Davis, J. J. Plaut, Tilman Spohn, M. S. Bell, Joseph R. Michalski, Karyn L. Rogers, D. Viola, Lynn J. Rothschild, Doris Breuer, Nathan Barba, Tullis C. Onstott, and Alfonso F. Davila
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010504 meteorology & atmospheric sciences ,Mars ,Astronomy and Astrophysics ,Mars Exploration Program ,01 natural sciences ,Astrobiology ,Frontier ,Extant taxon ,0103 physical sciences ,Wasser ,Exploration ,010303 astronomy & astrophysics ,Geology ,0105 earth and related environmental sciences - Abstract
The surface of Mars has been well mapped and characterized, yet the subsurface — the most likely place to find signs of extant or extinct life and a repository of useful resources for human exploration — remains unexplored. In the near future this is set to change.
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- 2019
24. Understanding Hypervelocity Sampling of Biosignatures in Space Missions
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Robert Hodyss, Michael Malaska, Andres Jaramillo-Botero, Morgan L. Cable, Amy E. Hofmann, and Jonathan I. Lunine
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Reactive molecular dynamics ,010504 meteorology & atmospheric sciences ,Atmosphere ,Space biosignatures ,Fatty Acids ,Sampling (statistics) ,01 natural sciences ,Agricultural and Biological Sciences (miscellaneous) ,Space exploration ,Mass Spectrometry ,Astrobiology ,Enceladus ,Space and Planetary Science ,0103 physical sciences ,Hypervelocity ,Amino and fatty acids fragmentation ,Environmental science ,Hypervelocity sampling ,Solar System ,Titan ,010303 astronomy & astrophysics ,Research Articles ,0105 earth and related environmental sciences - Abstract
The atomic-scale fragmentation processes involved in molecules undergoing hypervelocity impacts (HVIs; defined as >3 km/s) are challenging to investigate via experiments and still not well understood. This is particularly relevant for the consistency of biosignals from small-molecular-weight neutral organic molecules obtained during solar system robotic missions sampling atmospheres and plumes at hypervelocities. Experimental measurements to replicate HVI effects on neutral molecules are challenging, both in terms of accelerating uncharged species and isolating the multiple transition states over very rapid timescales (5 km/s, both consistent with recent experiments exploring HVI effects using impact-induced ionization and analysis via mass spectrometry and from the analysis of Enceladus organics in Cassini Data. From nanometer-sized ice Ih clusters, we establish that HVI energy is dissipated by ice casings through thermal resistance to the impact shock wave and that an upper fragmentation velocity limit exists at which ultimately any organic contents will be cleaved by the surrounding ice—this provides a fundamental path to characterize micrometer-sized ice grains. Altogether, these results provide quantifiable insights to bracket future instrument design and mission parameters.
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- 2021
25. An acoustic sensor network for planetary exploration
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Hyeong Jae Lee, Michael Malaska, Yoseph Bar-Cohen, Mircea Badescu, Xiaoqi Bao, and Stewart Sherrit
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Signal processing ,Frequency response ,Thunder ,Computer science ,Microphone ,Acoustics ,Mars Exploration Program ,Sonar ,Wireless sensor network ,Dust devil - Abstract
This paper investigates the concept of an acoustic sensor network that can monitor a variety of geophysical processes occurring on other planetary bodies. In many cases sound is naturally omnidirectional and travels at known speeds which depend on the composition and density of the atmosphere. The differences in the time of flight of signals received by a distributed microphone network can be used to locate the source of the sound. We suggest this property is ideal for mobile planetary robots and can be used to expand the exploration envelope considerably by directing camera pointing or rover path planning thus extending beyond line-of-sight exploration. Acoustic signatures have been used in a variety of fields (eg. sonar, heavy machinery) to identify and catalog sounds associated with a specific vessels and malfunctioning machinery. Our ears have cataloged hundreds of sounds and we continuously use these sounds both consciously and subconsciously to extract information about our surroundings. This paper investigates the use acoustic measurements on other planetary bodies that could be used to characterize specific environmental parameters such as rain droplet size, wind speed, thunder, or dust devil vortex diameter. The paper identified other important sound sources that are thought to occur on other bodies in our solar system include; booming or singing dunes, waves, rivers, streams, fluidfalls, geysers, hurricanes, tornados, ice flow, volcanoes, planetary quakes, avalanche, rock slides and ice cracking. In addition, this paper focused on issues associated with the development of appropriate sensors for the network including the specification of the sensitivity, frequency response, and directional response of each of the microphones in the network in order to aid in localization of sound sources. We also presented our initial development of the transducers for potential mission targets including Mars and Titan and investigated the use of signal processing techniques including windowing, time frequency plots and correlation techniques to resolve phase differences between sensors in the network to aid in localization. We also identified additional benefits of these sensor networks in that they could used as engineering sensors to diagnose mechanical malfunctions on a rover or lander actuators or mechanisms. We also noted that they could also enhance public outreach by adding sound to videos.
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- 2021
26. Science and technology requirements to explore caves in our Solar System
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John DeDecker, Kaj E. Williams, Dirk Schulze-Makuch, Norbert Schorghofer, Charity M. Phillips-Lander, P. Boston, Alberto G. Fairén, Uland Wong, J. W. Ashley, Cansu Demirel-Floyd, Amos Frumkin, Ana Z. Miller, Timothy N. Titus, Haley M. Sapers, Bodgan Onac, John E. Mylroie, Richard Leveille, Francesco Sauro, Armando Azua-Bustos, Kavya K. Manyapu, Gary L. Harris, Pablo de León, Leroy Chiao, Laura Kerber, Kyle Uckert, Matteo Massironi, Red Whittaker, Thomas H. Prettyman, Ali Agha-Mohammadi, Jo De Waele, Glen E. Cushing, J. Judson Wynne, Calvin Alexander Jr, Michael Malaska, Scott Parazynski, Heather Jones, Titus, Timothy, Wynne, J. Judson, Boston, Penny, Leon, Pablo de, Demirel-Floyd, Cansu, Jones, Heather, Sauro, Francesco, Uckert, Kyle, Aghamohammadi, Ali, Alexander, Calvin, Ashley, James W., Azua-Bustos, Armando, Chiao, Leroy, Cushing, Glen, DeDecker, John, Fairen, Alberto, Frumkin, Amo, Waele, Jo de, Harris, Gary L., Kerber, Laura, Léveillé, Richard J., Malaska, Mike, Manyapu, Kavya, Massironi, Matteo, Miller, Ana, Mylroie, John, Onac, Bodgan, Parazynski, Scott, Phillips-Lander, Charity, Prettyman, Thoma, Sapers, Haley, Schorghofer, Norbert, Schulze-Makuch, Dirk, Whittaker, Red, Williams, Kaj, and Wong, Uland
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geography ,Solar System ,Architectural engineering ,geography.geographical_feature_category ,InformationSystems_INFORMATIONINTERFACESANDPRESENTATION(e.g.,HCI) ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,GeneralLiterature_MISCELLANEOUS ,Cave ,cave ,ComputerSystemsOrganization_SPECIAL-PURPOSEANDAPPLICATION-BASEDSYSTEMS ,Science, technology and society ,Science and technology ,Geology ,ComputingMethodologies_COMPUTERGRAPHICS - Abstract
Research on planetary caves requires cross-planetary-body investigations spanning multiple disciplines, including geology, climatology, astrobiology, robotics, human exploration and operations. The community determined that a roadmap was needed to establish a common framework for planetary cave research. This white paper is our initial conception
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- 2021
27. The Science Case for a Titan Flagship-class Orbiter with Probes (White paper for the NRC Decadal Survey for Planetary Science and Astrobiology)
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Nixon, Conor A., James Abshire, Andrew Ashton, Barnes, Jason W., Nathalie Carrasco, Mathieu Choukroun, Athena Coustenis, Louis-Alexandre Couston, Edberg, Niklas J. T., Alexander Gagnon, Hofgartner, Jason D., Luciano Iess, Stéphane Le Mouélic, Rosaly Lopes, Juan Lora, Lorenz, Ralph D., Adrienn Luspay-Kuti, Michael Malaska, Kathleen Mandt, Marco Mastrogiuseppe, Erwan Mazarico, Marc Neveu, Taylor Perron, Jani Radebaugh, Sébastien Rodriguez, Farid Salama, Ashley Schoenfeld, Soderblom, Jason M., Anezina Solomonidou, Darci Snowden, Xioali Sun, Nicholas Teanby, Gabriel Tobie, Trainer, Melissa G., Tucker, Orenthal J., Turtle, Elizabeth P., Sandrine Vinatier, Véronique Vuitton, Xi Zhang, GSFC Planetary Systems Laboratory, NASA Goddard Space Flight Center (GSFC), Woods Hole Oceanographic Institution (WHOI), University of Idaho [Moscow, USA], PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), British Antarctic Survey (BAS), Natural Environment Research Council (NERC), Swedish Institute of Space Physics [Uppsala] (IRF), School of Oceanography [Seattle], University of Washington [Seattle], Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Yale University [New Haven], Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), University of Maryland [Baltimore], Massachusetts Institute of Technology (MIT), Brigham Young University (BYU), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), NASA Ames Research Center (ARC), University of California [Los Angeles] (UCLA), University of California, European Space Astronomy Centre (ESAC), European Space Agency (ESA), Central Washington University, School of Earth Sciences [Bristol], University of Bristol [Bristol], Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), and University of California [Santa Cruz] (UCSC)
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[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] - Abstract
13 pages, white paper submitted to the NRC Decadal Survey for Planetary Science and Astrobiology; International audience; We outline a flagship-class mission concept focused on studying Titan as a global system, with particular emphasis on the polar regions. Investigating Titan from the unique standpoint of a polar orbit would enable comprehensive global maps to uncover the physics and chemistry of the atmosphere, and the topography and geophysical environment of the surface and subsurface. The mission includes two key elements: (1) an orbiter spacecraft, which also acts as a data relay, and (2) one or more small probes to directly investigate Titan's seas and make the first direct measurements of their liquid composition and physical environment. The orbiter would carry a sophisticated remote sensing payload, including a novel topographic lidar, a long-wavelength surface-penetrating radar, a sub-millimeter sounder for winds and for mesospheric/thermospheric composition, and a camera and near-infrared spectrometer. An instrument suite to analyze particles and fields would include a mass spectrometer to focus on the interactions between Titan's escaping upper atmosphere and the solar wind and Saturnian magnetosphere. The orbiter would enter a stable polar orbit around 1500 to 1800 km, from which vantage point it would make global maps of the atmosphere and surface. One or more probes, released from the orbiter, would investigate Titan's seas in situ, including possible differences in composition between higher and lower latitude seas, as well as the atmosphere during the parachute descent. The number of probes, as well as the instrument complement on the orbiter and probe, remain to be finalized during a mission study that we recommend to NASA as part of the NRC Decadal Survey for Planetary Science now underway, with the goal of an overall mission cost in the "small flagship" category of ~$2 bn. International partnerships, similar to Cassini-Huygens, may also be included for consideration.
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- 2021
28. Plume Grain Sampling at Hypervelocity: Implications for Astrobiology Investigations
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Steve Fuerstenau, Sarah E. Waller, Nick Tallarida, Morgan E. C. Miller, Andres Jaramillo-Botero, Anton Belousov, Sally Burke, Bernd Abel, Morgan L. Cable, Frank Postberg, Fabian Klenner, Robert E. Continetti, R. P. Hodyss, James L. Lambert, Amy E. Hofmann, Z. Ulibarri, and Michael Malaska
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Hypervelocity ,Sampling (statistics) ,Environmental science ,Astrobiology ,Plume - Published
- 2021
29. A chemical composition map for Titan’s surface
- Author
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Ashley Schoenfeld, Rosaly M. C. Lopes, Yannis Markonis, Christophe Sotin, Bernard Schmitt, Athena Coustenis, Pierre Drossart, Christos Matsoukas, Kenneth J. Lawrence, Alice Le Gall, S. D. Wall, A. Solomonidou, Charles Elachi, Michael Malaska, California Institute of Technology (CALTECH), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Department of Earth, Planetary and Space Sciences [Los Angeles] (EPSS), University of California [Los Angeles] (UCLA), University of California-University of California, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), and Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Equator ,[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] ,Diffuse sky radiation ,Context (language use) ,Geophysics ,15. Life on land ,Albedo ,Latitude ,Atmosphere ,symbols.namesake ,13. Climate action ,symbols ,Radiometry ,Titan (rocket family) ,Geology - Abstract
The investigation of Titan’s surface chemical composition is of great importance for the understanding of the atmosphere-surface-interior system of the moon. The Cassini cameras and especially the Visual and infrared Mapping Spectrometer has provided a sequence of spectra showing the diversity of Titan’s surface spectrum from flybys performed during the 13 years of Cassini’s operation. In the 0.8-5.2 μm range, this spectro-imaging data showed that the surface consists of a multivariable geological terrain hosting complex geological processes. The data from the seven narrow methane spectral “windows” centered at 0.93, 1.08, 1.27, 1.59, 2.03, 2.8 and 5 μm provide some information on the lower atmospheric context and the surface parameters. Nevertheless, atmospheric scattering and absorption need to be clearly evaluated before we can extract the surface properties. In various studies (Solomonidou et al., 2014; 2016; 2018; 2019; 2020a, 2020b; Lopes et al., 2016; Malaska et al., 2016; 2020), we used radiative transfer modeling in order to evaluate the atmospheric scattering and absorption and securely extract the surface albedo of multiple Titan areas including the major geomorphological units. We also investigated the morphological and microwave characteristics of these features using Cassini RADAR data in their SAR and radiometry mode. Here, we present a global map for Titan’s surface showing the chemical composition constraints for the various units. The results show that Titan’s surface composition, at the depths detected by VIMS, has significant latitudinal dependence, with its equator being dominated by organic materials from the atmosphere and a very dark unknown material, while higher latitudes contain more water ice. The albedo differences and similarities among the various geomorphological units give insights on the geological processes affecting Titan’s surface and, by implication, its interior. We discuss our results in terms of origin and evolution theories.[1] Solomonidou, A., et al. (2014), J. Geophys. Res. Planets, 119, 1729; [2] Solomonidou, A., et al. (2016), Icarus, 270, 85; [3] Solomonidou, A., et al. (2018), J. Geophys. Res. Planets, 123, 489; [4] Solomonidou, A., et al. (2020a), Icarus, 344, 113338; [5] Solomonidou, A., et al. (2020b), A&A 641, A16; [6] Lopes, R., et al. (2016) Icarus, 270, 162; [7] Malaska, M., et al. (2016), Icarus 270, 130; [8] Malaska, M., et al. (2020), Icarus, 344, 113764.
- Published
- 2021
30. Titan: Earth-like on the Outside, Ocean World on the Inside
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Samuel Birch, Michael Malaska, Erika Barth, Thomas Cornet, Christophe Sotin, M. Y. Palmer, Rosaly M. C. Lopes, Melissa G. Trainer, Jason W. Barnes, Ella Sciamma-O'Brien, Elizabeth P. Turtle, Andrew J. Coates, Baptiste Journaux, D. Nna-Mvondo, Anezina Solomonidou, Claire Newman, Benoît Seignovert, Paul Corlies, Jordan K. Steckloff, Sarah M. Hörst, Sandrine Vinatier, Ed Sittler, Alexander E. Thelen, Alexander Hayes, Leonardo Regoli, Sébastien Rodriguez, Jennifer Hanley, Jani Radebaugh, Shannon MacKenzie, Conor A. Nixon, Juan M. Lora, E. C. Czaplinski, and Ralph D. Lorenz
- Subjects
Earth and Planetary Astrophysics (astro-ph.EP) ,Solar System ,Engineering ,business.industry ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrobiology ,Atmosphere ,Prebiotic chemistry ,symbols.namesake ,Physics - Atmospheric and Oceanic Physics ,Geophysics ,Planetary science ,Space and Planetary Science ,Atmospheric and Oceanic Physics (physics.ao-ph) ,Earth and Planetary Sciences (miscellaneous) ,symbols ,Earth (chemistry) ,business ,Titan (rocket family) ,Geology ,Astrophysics - Earth and Planetary Astrophysics - Abstract
Thanks to the Cassini-Huygens mission, Titan, the pale orange dot of Pioneer and Voyager encounters has been revealed to be a dynamic, hydrologically-shaped, organic-rich ocean world offering unparalleled opportunities to explore prebiotic chemistry. And while Cassini-Huygens revolutionized our understanding of each of the three layers of Titan--the atmosphere, the surface, and the interior--we are only beginning to hypothesize how these realms interact. In this paper, we summarize the current state of Titan knowledge and discuss how future exploration of Titan would address some of the next decade's most compelling planetary science questions. We also demonstrate why exploring Titan, both with and beyond the Dragonfly New Frontiers mission, is a necessary and complementary component of an Ocean Worlds Program that seeks to understand whether habitable environments exist elsewhere in our solar system., Submitted to the PSJ Focus Issue on Ocean World Exploration
- Published
- 2021
31. Deep Trek: Science of Subsurface Habitability & Life on Mars
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Daniel P. Glavin, Katarina Miljković, Joseph R. Michalski, Kristopher Sherrill, Heather Graham, Seth Krieger, Brian D. Wade, Charles D. Edwards, Louis Giersch, Beth N. Orcutt, Doris Breuer, William B. Brinckerhoff, J. Andy Spry, Thomas L. Kieft, Kalind Carpenter, Penelope J. Boston, Magdalena R. Osburn, Tilman Spohn, Atsuko Kobayashi, Fumio Inagaki, Matthew O. Schrenk, Jennifer G. Blank, Ákos Kereszturi, John D. Rummel, Hermes Hernan Bolivar-Torres, Christopher R. Webster, Shino Suzuki, John Hernlund, Jennifer C. McIntosh, Devanshu Jha, M. S. Bell, Velibor Cormarkovic, Ryan Timoney, Janice L. Bishop, Stalport Fabien, Michael A. Mischna, Robert E. Grimm, Lewis M. Ward, Matthias Grott, Kennda Lynch, Kris Zacny, Elodie Gloesener, Stewart Gault, Raju Manthena, Vincent Chevrier, Anthony Freeman, Vlada Stamenkovic, Giuseppe Etiope, Tullis C. Onstott, Yasuhito Sekine, Nathan Barba, Ceth W. Parker, Alexis S. Templeton, Larry Matthies, Varun Paul, Marc A. Hesse, John F. Mustard, Snehamoy Chatterjee, Cara Magnabosco, Roberto Orosei, Donald Ruffatto, María Paz Zorzano, Haley M. Sapers, A. F. C. Haldemann, Nigel Smith, Brian H. Wilcox, Kyle Uckert, Jorge Andres Torres Celis, S. Shkolyar, Sushil K. Atreya, Luther W. Beegle, Joseph L. Kirschvink, Jeffrey J. McDonnell, Eloise Marteau, Essam Heggy, J. D. Tarnas, Alberto G. Fairén, Morgan L. Cable, James W. Head, David A. Paige, Sharon Kedar, Renyu Hu, Woodward W. Fischer, Orkun Temel, Dirk Schulze-Makuch, Scott Howe, Rachel L. Harris, Tomohiro Usui, Travis Gabriel, Ana-Catalina Plesa, Ryan Woolley, Barbara Sherwood-Lollar, Oliver Warr, Edgard G. Rivera-Valentín, Charles S. Cockell, Bernadett Pál, Cedric Schmelzbach, Sarah Stewart Johnson, Ali-akbar Agha-mohammadi, Michael Malaska, Mariko Burgin, and Patrick McGarey
- Subjects
Habitability ,Life on Mars ,GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries) ,Geology ,Astrobiology - Abstract
Bulletin of the AAS, 53 (4)
- Published
- 2021
32. New Frontiers Titan Orbiter
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Nicholas A. Lombardo, Shawn Brueshaber, Kerry Ramirez, Shannon MacKenzie, Marc Neveu, Alfred S. McEwen, Thomas Cornet, R. T. Desai, Jason D. Hofgartner, Ella Sciamma-O'Brien, Elizabeth P. Turtle, Ed Sittler, Thomas W. Momary, Jani Radebaugh, Stéphane Le Mouélic, Steve Vance, Ari H.D. Koeppel, Paolo Tortora, Ralph D. Lorenz, Patrice Coll, Miriam Rengel, D. Nna-Mvondo, Paul Corlies, Christopher P. McKay, Nicholas A Teanby, L. R. Schurmeier, Tilmann Denk, Gregory A. Neumann, Mark Gurwell, Jason M. Soderblom, Jennifer Hanley, Ajay B. Limaye, Mathieu G.A. Lapotre, Anezina Solomonidou, Daniel Cordier, Sarah A. Fagents, Lori K. Fenton, Conor A. Nixon, Sébastien Lebonnois, Samuel Birch, Chloé Daudon, Sébastien Rodriguez, Michael Heslar, Juan M. Lora, Liliana Lefticariu, Ross A. Beyer, Leonardo Regoli, Chuanfei Dong, E. C. Czaplinski, Farid Salama, Paul O. Hayne, Michael Malaska, A. D. Maue, R. N. Schindhelm, Athena Coustenis, Emilie Royer, Alexander G. Hayes, Catherine D. Neish, Jason W. Barnes, Sandrine Vinatier, Jordan Stekloff, Andrew J. Coates, Erich Karkoschka, Mark Elowitz, J. Michael Battalio, Timothy A. Goudge, Sarah M. Hörst, D. M. Burr, Morgan L. Cable, Shiblee R. Barua, Tuan H. Vu, Rosaly M. C. Lopes, and Rajani D. Dhingra
- Subjects
Orbiter ,symbols.namesake ,law ,spacecraft ,symbols ,decadal survey ,White paper ,Titan (rocket family) ,Titan ,Geology ,Astrobiology ,law.invention - Published
- 2021
33. Deep Trek: Mission Concepts for Exploring Subsurface Habitability & Life on Mars — A Window into Subsurface Life in the Solar System
- Author
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Daniel P. Glavin, Kristopher Sherrill, Lewis M. Ward, Tomohiro Usui, Jennifer G. Blank, Atsuko Kobayashi, Matthias Grott, Janice L. Bishop, Rachel L. Harris, Charles D. Edwards, Orkun Temel, Alexis S. Templeton, Travis Gabriel, Larry Matthies, Haley M. Sapers, Vincent Chevrier, Eloise Marteau, Ceth W. Parker, Sarah Stewart Johnson, Patrick McGarey, Vlada Stamenkovic, Ana-Catalina Plesa, Joseph R. Michalski, Ryan Woolley, Seth Krieger, Michael Mischna, John D. Rummel, Sharon Kedar, Devanshu Jha, Sushil K. Atreya, Heather Graham, Roberto Orosei, Brian D. Wade, Louis Giersch, Matthew O. Schrenk, Alberto G. Fairén, Dirk Schulze-Makuch, Ákos Kereszturi, Beth N. Orcutt, Doris Breuer, Kalind Carpenter, Snehamoy Chatterjee, Velibor Cormarkovic, Cara Magnabosco, Anthony Freeman, Scott Howe, Donald Ruffatto, Oliver Warr, Robert E. Grimm, Kris Zacny, Shino Suzuki, Hermes Hernan Bolivar-Torres, Penelope J. Boston, John Hernlund, Jeffrey J. McDonnell, Barbara Sherwood-Lollar, Stewart Gault, Joseph L. Kirschvink, Yasuhito Sekine, Jennifer C. McIntosh, Morgan L. Cable, Cedric Schmelzbach, Renyu Hu, Fumio Inagaki, Stalport Fabien, Nigel Smith, John F. Mustard, William B. Brinckerhoff, Nathan Barba, Ali-akbar Agha-mohammadi, Michael Malaska, Mariko Burgin, Varun Paul, Essam Heggy, J. D. Tarnas, Jorge Andres Torres Celis, Katarina Miljković, Bernadett Pál, Woodward W. Fischer, A. F. C. Haldemann, Kennda Lynch, Elodie Gloesener, Edgard G. Rivera-Valentín, J. Andy Spry, Charles S. Cockell, Magdalena R. Osburn, Marc A. Hesse, Luther W. Beegle, Tilman Spohn, Tullis C. Onstott, M. S. Bell, Kyle Uckert, María Paz Zorzano, S. Shkolyar, David A. Paige, Ryan Timoney, Raju Manthena, Giuseppe Etiope, Chris Webster, Brian H. Wilcox, Thomas L. Kieft, and James W. Head
- Subjects
Solar System ,Habitability ,Window (computing) ,Life on Mars ,GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries) ,Jet propulsion ,Geology ,Astrobiology - Abstract
Charles D. Edwards (Jet Propulsion Laboratory, California Institute of Technology). Co-Authors: 1. Vlada Stamenkovic Jet Propulsion Laboratory, California Institute of Technology; 2. Penelope Boston NASA Ames; 3. Kennda Lynch LPI/USRA … et al.
- Published
- 2021
34. The chemical composition of impact craters on Titan
- Author
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Christos Matsoukas, Athena Coustenis, Catherine D. Neish, Bernard Schmitt, Ioannis Baziotis, Michael Malaska, Kenneth J. Lawrence, Olivier Witasse, Rosaly M. C. Lopes, Anezina Solomonidou, Ashley Schoenfeld, Nico Altobelli, Pierre Drossart, Coustenis Athena, Alice Le Gall, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Agence Spatiale Européenne (ESA), European Space Agency (ESA), University of Western Ontario (UWO), European Space Astronomy Centre (ESAC), Czech University of Life Sciences Prague (CZU), Department of Earth Sciences [London, ON], Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), European Space Research and Technology Centre (ESTEC), Department of Earth, Planetary and Space Sciences [Los Angeles] (EPSS), University of California [Los Angeles] (UCLA), University of California-University of California, Royal Institute of Technology [Stockholm] (KTH ), and Agricultural University of Athens
- Subjects
geography ,geography.geographical_feature_category ,Alluvial fan ,[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] ,15. Life on land ,symbols.namesake ,Atmospheric radiative transfer codes ,Impact crater ,13. Climate action ,[SDU]Sciences of the Universe [physics] ,Middle latitudes ,symbols ,Radiative transfer ,Ejecta blanket ,Titan (rocket family) ,Chemical composition ,Geomorphology ,Geology - Abstract
We investigate nine Titan impact craters using Visual and Infrared Mapping Spectrometer (VIMS) data and a radiative transfer code (RT) [e.g. 1] in addition to emissivity data, in order to constrain the spectral behavior and composition of the craters. Past studies have looked at the chemical composition of impact craters either by using qualitative comparisons between craters [e.g. 2;3] or by combining all craters into a single unit [4], rather than separating them by geographic location or degradation state. Here, we use a radiative transfer model to first estimate the atmospheric contribution to the data, then extract the surface albedos of the impact crater subunits, and finally constrain their composition by using a library of candidate Titan materials. Following the general characterization of the impact craters, we study two impact crater subunits, the ‘crater floor’, which refers to the bottom of a crater, and the ‘ejecta blanket’, which is the material thrown out of the crater during an impact event. The results show that Titan’s mid-latitude plain craters: Afekan, Soi, and Forseti, in addition to Sinlap and Menrva are enriched in an OH-bearing constituent (likely water-ice) in an organic based mixture, while the equatorial dune craters: Selk, Ksa, Guabonito, and Santorini, appear to be purely composed of organic material (mainly unknown dune dark material). This follows the pattern seen in [4], where midlatitude alluvial fans, undifferentiated plains, and labyrinths were found to consist of a tholin-like and water-ice mixture, while the equatorial undifferentiated plains, hummocky terrains, dunes, and variable plains were found to consist of a dark material and tholin-like mixture in their very top layers. These observations also agree with the evolution scenario proposed by [3], wherein the impact cratering process produces a mixture of organic material and water ice, which is later “cleaned” through fluvial erosion in the midlatitude plains; a cleaning process that does not appear to operate in the equatorial dunes, which seem to be quickly covered by a thin layer of sand sediment. This scenario agrees with other works that suggest that atmospheric deposition is similar in the low-latitudes and midlatitudes on Titan, but with more rain falling onto the higher latitudes causing additional processing of materials in those regions [e.g. 5]. In either case, it appears that active processes are working to shape the surface of Titan, and it remains a dynamic world in the present day.[1] Hirtzig, M., et al. (2013). Icarus, 226, 470–486; [2] Neish, C.D., et al. (2015), Geophys. Res. Lett. 42, 3746–3754; [3] Werynski, A., et al. (2019), Icarus, 321, 508-521; [4] Solomonidou, A., et al. (2018), J. Geophys. Res, 123, 2, 489-507; [5] Neish, A.C., et al. (2016), Icarus, 270, 114–129.
- Published
- 2020
35. Diverse evolution of mountains and hummocks on Titan as observed by the Cassini RADAR altimeter
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A.G. Hayes, V. Poggiali, L. R. Schurmeier, D. E. Lalich, Michael Malaska, and Marco Mastrogiuseppe
- Subjects
Elevation ,Astronomy and Astrophysics ,Terrain ,law.invention ,Footprint ,symbols.namesake ,Mountain formation ,Space and Planetary Science ,Radar altimeter ,law ,symbols ,Radar ,Titan (rocket family) ,Geology ,Remote sensing - Abstract
Mountain formation and evolution on Titan is poorly understood, due in part to a lack of high-resolution topographic data. By applying advanced processing techniques, we are able to increase the along-track spatial resolution of the Cassini RADAR altimeter by up to a factor of ten, enabling more detailed analysis. A survey of mountainous and hummocky terrain reveals a unique, characteristic waveform shape. By modeling reflections from different landscapes, we are able to show that these waveforms contain sub-resolution topographical information. We found that mountain elevation on Titan varies greatly over short distances, and evidence suggests that many mountain ranges on Titan have been eroded down to the plains level even within a single high-resolution radar footprint.
- Published
- 2022
36. The Science Case for a Titan Flagship-class Orbiter with Probes
- Author
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Conor A. Nixon, Jason M. Soderblom, Xi Zhang, Athena Coustenis, Sébastien Rodriguez, Jani Radebaugh, Jason W. Barnes, Ralph D. Lorenz, Andrew D. Ashton, Mathieu Choukroun, Kathleen Mandt, Adrienn Luspay-Kuti, Elizabeth P. Turtle, Juan M. Lora, Ashley Schoenfeld, Alexander C. Gagnon, Niklas J. T. Edberg, Louis-Alexandre Couston, Stéphane Le Mouélic, Marco Mastrogiuseppe, Gabriel Tobie, Véronique Vuitton, Sandrine Vinatier, Erwan Mazarico, Nathalie Carrasco, X. Sun, Taylor Perron, Darci Snowden, Orenthal J. Tucker, Melissa G. Trainer, Marc Neveu, Luciano Iess, Anezina Solomonidou, Farid Salama, Michael Malaska, Jason D. Hofgartner, Rosaly M. C. Lopes, Nicholas A Teanby, James B. Abshire, Coustenis, Athena, NASA Goddard Space Flight Center (GSFC), Woods Hole Oceanographic Institution (WHOI), University of Idaho [Moscow, USA], PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Swedish Institute of Space Physics [Uppsala] (IRF), and University of Washington [Seattle]
- Subjects
Solar System ,[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] ,FOS: Physical sciences ,[SDU.ASTR.EP] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] ,7. Clean energy ,Astrobiology ,law.invention ,Atmosphere ,symbols.namesake ,Orbiter ,Planet ,law ,Saturn ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,Physics::Atmospheric and Oceanic Physics ,Earth and Planetary Astrophysics (astro-ph.EP) ,Spacecraft ,business.industry ,Planetary science ,13. Climate action ,Physics::Space Physics ,symbols ,Environmental science ,Astrophysics::Earth and Planetary Astrophysics ,Titan (rocket family) ,business ,Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Earth and Planetary Astrophysics - Abstract
We outline a flagship-class mission concept focused on studying Titan as a global system, with particular emphasis on the polar regions. Investigating Titan from the unique standpoint of a polar orbit would enable comprehensive global maps to uncover the physics and chemistry of the atmosphere, and the topography and geophysical environment of the surface and subsurface. The mission includes two key elements: (1) an orbiter spacecraft, which also acts as a data relay, and (2) one or more small probes to directly investigate Titan's seas and make the first direct measurements of their liquid composition and physical environment. The orbiter would carry a sophisticated remote sensing payload, including a novel topographic lidar, a long-wavelength surface-penetrating radar, a sub-millimeter sounder for winds and for mesospheric/thermospheric composition, and a camera and near-infrared spectrometer. An instrument suite to analyze particles and fields would include a mass spectrometer to focus on the interactions between Titan's escaping upper atmosphere and the solar wind and Saturnian magnetosphere. The orbiter would enter a stable polar orbit around 1500 to 1800 km, from which vantage point it would make global maps of the atmosphere and surface. One or more probes, released from the orbiter, would investigate Titan's seas in situ, including possible differences in composition between higher and lower latitude seas, as well as the atmosphere during the parachute descent. The number of probes, as well as the instrument complement on the orbiter and probe, remain to be finalized during a mission study that we recommend to NASA as part of the NRC Decadal Survey for Planetary Science now underway, with the goal of an overall mission cost in the "small flagship" category of ~$2 bn. International partnerships, similar to Cassini-Huygens, may also be included for consideration., 13 pages, white paper submitted to the NRC Decadal Survey for Planetary Science and Astrobiology
- Published
- 2020
37. The chemical composition of impact craters on Titan
- Author
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Ioannis Baziotis, Rosaly M. C. Lopes, Michael Malaska, Pierre Drossart, Kenneth J. Lawrence, Ashley Schoenfeld, Christos Matsoukas, Anezina Solomonidou, Alyssa Werynski, Athena Coustenis, Olivier Witasse, Nicolas Altobelli, Catherine D. Neish, Alice Le Gall, European Space Astronomy Centre (ESAC), European Space Agency (ESA), Department of Earth Sciences [London, ON], University of Western Ontario (UWO), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), European Space Research and Technology Centre (ESTEC), Department of Earth, Planetary and Space Sciences [Los Angeles] (EPSS), University of California [Los Angeles] (UCLA), University of California-University of California, Royal Institute of Technology [Stockholm] (KTH ), Agricultural University of Athens, NASA-California Institute of Technology (CALTECH), and Institut de l'élevage (IDELE)
- Subjects
geography ,geography.geographical_feature_category ,Alluvial fan ,[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] ,Mineralogy ,Fluvial ,symbols.namesake ,Atmospheric radiative transfer codes ,Impact crater ,13. Climate action ,[SDU]Sciences of the Universe [physics] ,symbols ,Radiative transfer ,Ejecta blanket ,Titan (rocket family) ,Chemical composition ,Geology ,ComputingMilieux_MISCELLANEOUS - Abstract
International audience; We investigate nine Titan impact craters using Visual and Infrared Mapping Spectrometer (VIMS) data and a radiative transfer code (RT) [e.g. 1] in addition to emissivity data, in order to constrain the spectral behavior and composition of the craters. Past studies have looked at the chemical composition of impact craters either by using qualitative comparisons between craters [e.g. 2;3] or by combining all craters into a single unit [4], rather than separating them by geographic location or degradation state. Here, we use a radiative transfer model to first estimate the atmospheric contribution to the data, then extract the surface albedos of the impact crater subunits, and finally constrain their composition by using a library of candidate Titan materials. Following the general characterization of the impact craters, we study two impact crater subunits, the 'crater floor', which refers to the bottom of a crater, and the 'ejecta blanket', which is the material thrown out of the crater during an impact event. The results show that Titan's mid-latitude plain craters: Afekan, Soi, and Forseti, in addition to Sinlap and Menrva are enriched in an OH-bearing constituent (likely water-ice) in an organic based mixture, while the equatorial dune craters: Selk, Ksa, Guabonito, and Santorini, appear to be purely composed of organic material (mainly unknown dune dark material). This follows the pattern seen in [4], where midlatitude alluvial fans, undifferentiated plains, and labyrinths were found to consist of a tholin-like and water-ice mixture, while the equatorial undifferentiated plains, hummocky terrains, dunes, and variable plains were found to consist of a dark material and tholin-like mixture in their very top layers. These observations also agree with the evolution scenario proposed by [3], wherein the impact cratering process produces a mixture of organic material and water ice, which is later "cleaned" through fluvial erosion in the midlatitude plains; a cleaning process that does not appear to operate in the equatorial dunes, which seem to be quickly covered by a thin layer of sand sediment. This scenario agrees with other works that suggest that atmospheric deposition is similar in the low-latitudes and midlatitudes on Titan, but with more rain falling onto the higher latitudes causing additional processing of materials in those regions [e.g. 5]. In either case, it appears that active processes are working to shape the surface of Titan, and it remains a dynamic world in the present day.[1] Hirtzig, M., et al. (2013). Icarus, 226, 470-486; [2] Neish, C.D., et al. (2015), Geophys. Res. Lett. 42, 3746-3754; [3] Werynski, A., et al. (2019), Icarus, 321, 508-521; [4] Solomonidou, A., et al. (2018), J. Geophys. Res, 123, 2, 489-507; [5] Neish, A.C., et al. (2016), Icarus, 270, 114-129.&
- Published
- 2020
38. Terrain Relative Navigation for Guided Descent on Titan
- Author
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Robert A. Hewitt, Michael Malaska, Evgeniy Sklyanskiy, Marco B. Quadrelli, Larry Matthies, Brandon Rothrock, Shreyansh Daftry, Joshua Yurtsever, Anthony B. Davis, Jeff Delaune, and Aaron Schutte
- Subjects
010504 meteorology & atmospheric sciences ,Terrain ,Mars Exploration Program ,Map matching ,01 natural sciences ,law.invention ,symbols.namesake ,Radar altimeter ,law ,Inertial measurement unit ,0103 physical sciences ,symbols ,Titan (rocket family) ,010303 astronomy & astrophysics ,Image resolution ,Geology ,Inertial navigation system ,0105 earth and related environmental sciences ,Remote sensing - Abstract
Titan's dense atmosphere, low gravity, and high winds at high altitudes create descent times of >90 minutes with standard entry/descent/landing (EDL) architectures and result in large unguided landing ellipses, with 99% values of ~110x110 km and 149x72 km in recent Titan lander proposals. Enabling precision landing on Titan could increase science return for the types of missions proposed to date and make additional types of landing sites accessible, opening up new possibilities for science investigations. Precision landing on Titan has unique challenges, because the hazy atmosphere makes it difficult to see the surface and because it requires guided descent with divert ranges that are one to two orders of magnitude larger than needed for other target bodies, i.e. up to on the order of 100 km. It is conceivable that such a divert capability could be provided economically by a parafoil or other steerable aerodynamic decelerator deployed several 10s of km above the surface. The long descent times lead to large inertial navigation errors, hence a need for terrain relative navigation (TRN). This would require a TRN capability that can operate at such altitudes, despite challenges of seeing the surface sufficiently clearly and of depending on map products that are two orders of magnitude lower in spatial resolution than those for Mars and airless bodies. This paper addressed the TRN problem for Titan guided descent, assuming parafoil deployment at an altitude around 40 km. We define a notional sensor suite including an inertial measurement unit (IMU), a radar altimeter, and two descent cameras, with spectral responses in the visible/near infrared (VNIR) (~0.5 to 1 um) and short wave infrared (SWIR) (~2.0 to 2.1 um), Due to the low resolution of current Titan map products, we define two altitude regimes (above and below ~ 20 km) that need different navigation techniques. Map matching is applicable in the upper regime, but challenging or infeasible in the lower one. Feature tracking with decent imagery is desirable in the lower regime, but challenging in the upper one. We derive image contrast requirements for TRN from prior literature and create models of achievable image contrast by radiative transfer modeling; this shows that the requirements should be achievable for a SWIR descent camera in the upper regime, and that a VNIR descent camera is preferable in the lower regime. We then develop algorithms for map matching and feature tracking with descent images and test these with synthetic images created from Cassini/Huygens data sets and our radiative transfer model. We also introduce new possibilities for TRN based on the potential to discriminate some specific types of terrain onboard in descent imagery, such as lake vs adjacent ground and dune vs interdune. We use sensor measurement noise models in simulations of state estimation with an extended Kalman filter that includes coordinates of a set of tracked features in the state vector. Case studies were done for two notional landing sites, one in a site with only dry ground and one in a Titan lake district. In both cases, the filter error model shows 3σ position error at touchdown on the order of 2 km. More work is needed to validate these results with higher fidelity camera models and larger data sets, but this is very promising.
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- 2020
39. Modeling transmission windows in Titan's lower troposphere: Implications for infrared spectrometers aboard future aerial and surface missions
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Alexander G. Hayes, Michael Malaska, James J. Wray, Sarah M. Hörst, Jason D. Hofgartner, Lucas Liuzzo, Ralph D. Lorenz, Elizabeth P. Turtle, George D. McDonald, Morgan L. Cable, Máté Ádámkovics, Paul Corlies, and Jacob Buffo
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Earth and Planetary Astrophysics (astro-ph.EP) ,010504 meteorology & atmospheric sciences ,Spectrometer ,Infrared ,FOS: Physical sciences ,Astronomy and Astrophysics ,Observable ,01 natural sciences ,Methane ,Astrobiology ,Troposphere ,chemistry.chemical_compound ,symbols.namesake ,Atmospheric radiative transfer codes ,chemistry ,Space and Planetary Science ,0103 physical sciences ,symbols ,Environmental science ,Cyanoacetylene ,Titan (rocket family) ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences ,Astrophysics - Earth and Planetary Astrophysics - Abstract
From orbit, the visibility of Titan's surface is limited to a handful of narrow spectral windows in the near-infrared (near-IR), primarily from the absorption of methane gas. This has limited the ability to identify specific compounds on the surface -- to date Titan's bulk surface composition remains unknown. Further, understanding of the surface composition would provide insight into geologic processes, photochemical production and evolution, and the biological potential of Titan's surface. One approach to obtain wider spectral coverage with which to study Titan's surface is by decreasing the integrated column of absorbers (primarily methane) and scatterers between the observer and the surface. This is only possible if future missions operate at lower altitudes in Titan's atmosphere. Herein, we use a radiative transfer model to measure in detail the absorption through Titan's atmosphere from different mission altitudes, and consider the impacts this would have for interpreting reflectance measurements of Titan's surface. Over our modeled spectral range of 0.4 - 10 micron, we find that increases in the width of the transmission windows as large as 317% can be obtained for missions performing remote observations at the surface. However, any appreciable widening of the windows requires onboard illumination. Further, we make note of possible surface compounds that are not currently observable from orbit, but could be identified using the wider windows at low altitudes. These range from simple nitriles such as cyanoacetylene, to building blocks of amino acids such as urea. Finally, we discuss the implications that the identifications of these compounds would have for Titan science., Comment: 52 pages, 6 figures, Icarus 2020
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- 2020
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40. A global geomorphologic map of Saturn’s moon Titan
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M. Florence, R. M. C. Lopes, Alexander G. Hayes, Samuel Birch, Michael Malaska, A. Solomonidou, A. Le Gall, Jani Radebaugh, T. Verlander, David A. Williams, Ashley Schoenfeld, Elizabeth Turtle, S. D. Wall, Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Department of Earth, Planetary and Space Sciences [Los Angeles] (EPSS), University of California [Los Angeles] (UCLA), University of California-University of California, European Space Astronomy Centre (ESAC), European Space Agency (ESA), Department of Astronomy [Ithaca], Cornell University [New York], Arizona State University [Tempe] (ASU), Department of Geological Sciences [BYU], Brigham Young University (BYU), School of Civil Engineering and Environmental Science [Norman] (CEES), University of Oklahoma (OU), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), and Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)
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Solar System ,010504 meteorology & atmospheric sciences ,Equator ,Astronomy and Astrophysics ,Terrain ,Global Map ,Geophysics ,15. Life on land ,01 natural sciences ,Article ,law.invention ,Sedimentary depositional environment ,Orbiter ,symbols.namesake ,13. Climate action ,law ,[SDU]Sciences of the Universe [physics] ,0103 physical sciences ,symbols ,Titan (rocket family) ,010303 astronomy & astrophysics ,Relative dating ,Geology ,0105 earth and related environmental sciences - Abstract
International audience; Titan has an active methane-based hydrologic cycle1 that has shaped a complex geologic landscape2, making its surface one of most geologically diverse in the Solar System. Despite the differences in materials, temperatures and gravity fields between Earth and Titan, many of their surface features are similar and can be interpreted as products of the same geologic processes3. However, Titan’s thick and hazy atmosphere has hindered the identification of its geologic features at visible wavelengths and the study of its surface composition4. Here we identify and map the major geological units on Titan’s surface using radar and infrared data from the Cassini orbiter spacecraft. Correlations between datasets enabled us to produce a global map even where datasets were incomplete. The spatial and superposition relations between major geological units reveals the likely temporal evolution of the landscape and provides insight into the interacting processes driving its evolution. We extract the relative dating of the various geological units by observing their spatial superposition in order to get information on the temporal evolution of the landscape. The dunes and lakes are relatively young, whereas the hummocky or mountainous terrains are the oldest on Titan. Our results also show that Titan’s surface is dominated by sedimentary or depositional processes with a clear latitudinal variation, with dunes at the equator, plains at mid-latitudes and labyrinth terrains and lakes at the poles.
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- 2020
41. Prospects for mineralogy on Titan
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Michael Malaska, Helen E. Maynard-Casely, Mathieu Choukroun, Tuan H. Vu, Morgan L. Cable, and Robert Hodyss
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symbols.namesake ,Geophysics ,010504 meteorology & atmospheric sciences ,Geochemistry and Petrology ,0103 physical sciences ,symbols ,Environmental science ,Titan (rocket family) ,010303 astronomy & astrophysics ,01 natural sciences ,0105 earth and related environmental sciences ,Astrobiology - Published
- 2018
42. Exploration of organic minerals on Saturn's moon Titan
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Helen E. Maynard-Casely, Rob Hodyss, Tuan Vu, Michael Malaska, Mathieu Choukroun, Morgan Cable, and Tom Runčevski
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Inorganic Chemistry ,Structural Biology ,General Materials Science ,Physical and Theoretical Chemistry ,Condensed Matter Physics ,Biochemistry - Published
- 2021
43. Sampling Plume Deposits on Enceladus’ Surface to Explore Ocean Materials and Search for Traces of Life or Biosignatures
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Robert Hodyss, Tyler Okamoto, Morgan L. Cable, Dario Riccobono, Michael Malaska, Aaron C. Noell, Tom Nordheim, Scott Moreland, Edith C. Fayolle, Mircea Badescu, Kris Zacny, Andrii Murdza, Erland M. Schulson, Eloise Marteau, Paul Backes, Mathieu Choukroun, and Jamie Molaro
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Geophysics ,Space and Planetary Science ,Earth and Planetary Sciences (miscellaneous) ,Sampling (statistics) ,Astronomy and Astrophysics ,Enceladus ,Geology ,Astrobiology ,Plume - Abstract
Enceladus is unique as an astrobiology target in that it hosts an active plume sourced directly from its habitable subsurface ocean. Ice particles from the plume contain geochemical constituents that are diagnostic of the ocean conditions, and may hold traces of life and/or biosignatures, if they exist. Up to 93% of the plume particles fall back onto the surface of Enceladus. The low radiation environment and present-day activity are favorable to the preservation of any complex organics and putative biosignatures contained within these particles. Laboratory experiments and modeling suggest that plume deposits would likely be weakly consolidated and relatively easy to sample. Sampling systems like a dual rasp, under development to achieve technology readiness level (TRL) 5 in 2021, would enable a landed mission on Enceladus’ surface to acquire large amounts of surface materials, a requirement for analysis of trace constituents. A landed mission on Enceladus could greatly enhance our understanding of the chemical makeup of plume particles and the subsurface ocean, and seek traces of life and/or biosignatures.
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- 2021
44. Laboratory measurements of nitrogen dissolution in Titan lake fluids
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Alexander G. Hayes, Michael Malaska, Gigja Hollyday, Jonathan I. Lunine, Ralph D. Lorenz, Robert Hodyss, and Jason D. Hofgartner
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010504 meteorology & atmospheric sciences ,chemistry.chemical_element ,Astronomy and Astrophysics ,01 natural sciences ,Nitrogen ,Methane ,Lower temperature ,Astrobiology ,chemistry.chemical_compound ,symbols.namesake ,chemistry ,Space and Planetary Science ,Environmental chemistry ,0103 physical sciences ,Nitrogen gas ,symbols ,Environmental science ,Liquid bubble ,Solubility ,Titan (rocket family) ,010303 astronomy & astrophysics ,Dissolution ,0105 earth and related environmental sciences - Abstract
We obtained laboratory measurements of nitrogen solubility in mixed solutions of ethane and methane at temperatures and pressures relevant to Titan's lakes and seas. Our results show that nitrogen solubility is increased at higher methane concentration, lower temperature, and higher pressure. We developed an empirical fit that agrees well with our measurements. We show that significant volumes of nitrogen gas will be released from Titan lake fluids on heating, and that significant volumes of nitrogen gas will be absorbed by Titan lake fluids on cooling. The densities of the lake fluids will be affected by nitrogen dissolution. We also show that mixing of two cryogenic fluids of different composition can lead to the release of large amounts of nitrogen gas. This has implications for lake fluids, bubble formation, geological phenomena, and also for future landed missions on the surface of Titan. We find in particular that methane-rich lakes at lower temperatures on Titan will be the most sensitive to changes in surface conditions, either cooling, heating, or compositional mixing.
- Published
- 2017
45. Electrification of sand on Titan and its influence on sediment transport
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George D. McDonald, Devon M. Burr, Michael Malaska, J. S. Méndez Harper, Josef Dufek, J. McAdams, James J. Wray, and Alexander G. Hayes
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geography ,Solar System ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Granular material ,01 natural sciences ,Astrobiology ,symbols.namesake ,Volcano ,Saltation (geology) ,0103 physical sciences ,symbols ,General Earth and Planetary Sciences ,Titan (rocket family) ,010303 astronomy & astrophysics ,Sediment transport ,Geomorphology ,Geology ,Magnetosphere particle motion ,Triboelectric effect ,0105 earth and related environmental sciences - Abstract
Triboelectric, or frictional, charging is a ubiquitous yet poorly understood phenomenon in granular flows. Recognized in terrestrial volcanic plumes and sand storms, such electrification mechanisms are possibly present on Titan. There, dunes and plains of low-density organic particles blanket extensive regions of the surface. Unlike Earth, Titan hosts granular reservoirs whose physical and chemical properties possibly enhance the effects of charging on particle motion. Here we demonstrate in laboratory tumbler experiments under atmospheric conditions and using organic materials analogous to Titan that Titan sands can readily charge triboelectrically. We suggest that the resulting electrostatic forces are strong enough to promote aggregation of granular materials and affect sediment transport on Titan. Indeed, our experiments show that electrostatic forces may increase the saltation threshold for grains by up to an order of magnitude. Efficient electrification may explain puzzling observations on Titan such as the mismatch between dune orientations and inferred wind fields. We conclude that, unlike other Solar System bodies, nanometre-scale electrostatic processes may shape the geomorphological features of Titan across the moon’s surface. Frictional charging of granular materials may readily occur on Saturn’s moon Titan. Laboratory experiments under Titan-like conditions suggest that the resulting electrostatic forces are strong enough to affect sand transport on Titan.
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- 2017
46. Titan as Revealed by the Cassini Radar
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Federico Tosi, L. A. Soderblom, Charles Elachi, G. Mitri, Zhimeng Zhang, Alexander G. Hayes, S. D. Wall, Jason M. Soderblom, P. Paillou, Elizabeth P. Turtle, Richard West, R. L. Kirk, Gian Gabriele Ori, Tom G. Farr, Howard A. Zebker, Claudia Notarnicola, Paul Corlies, M. Mastroguiseppe, Jason W. Barnes, Antoine Lucas, K. L. Mitchell, Jason D. Hofgartner, Bryan Stiles, Athena Coustenis, Valerio Poggiali, A. Solomonidou, Cyril Grima, Roberto Orosei, O. Karatekin, E. R. Stofan, Jani Radebaugh, Spd Birch, Rmc Lopes, Domenico Casarano, A. LeGall, P Encrenaz, Michael Malaska, Charles A. Wood, Flora Paganelli, Douglas J. Hemingway, Daniele Riccio, Sebastien Rodriguez, Catherine D. Neish, M. A. Janssen, R. D. Lorenz, Paul Ries, Jonathan I. Lunine, Ashley Schoenfeld, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Astronomy [Ithaca], Cornell University, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Astrogeology Science Center [Flagstaff], United States Geological Survey [Reston] (USGS), University of Arizona, Lunar and Planetary Laboratory [Tucson] (LPL), Università degli Studi di Roma 'La Sapienza' [Rome], Laboratoire de Planétologie et Géodynamique UMR6112 (LPG), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Nantes - Faculté des Sciences et des Techniques, Université de Nantes (UN)-Université de Nantes (UN)-Université d'Angers (UA), Florida Institute of Technology [Melbourne], Institut de génétique humaine (IGH), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Service de cardiologie [Hôpital Nord - APHM], Aix Marseille Université (AMU)-Assistance Publique - Hôpitaux de Marseille (APHM)- Hôpital Nord [CHU - APHM], Observatoire Bordeaux, Université Sciences et Technologies - Bordeaux 1, Department of Geological Sciences [BYU], Brigham Young University (BYU), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Department of Earth, Planetary and Space Sciences [Los Angeles] (EPSS), University of California [Los Angeles] (UCLA), University of California-University of California, Proxemy Research Inc, Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Wheeling Jesuit University, Department of Electrical Engineering [Stanford], Stanford University [Stanford], Istituto di Ricerca per la Protezione Idrogeologica [Bari] (IRPI), Consiglio Nazionale delle Ricerche [Roma] (CNR), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Swedish Institute of Space Physics [Uppsala] (IRF), Miller Institute for Basic Research in Science, University of California [Berkeley], Royal Observatory of Belgium [Brussels], Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), International Research School of Planetary Sciences [Pescara] (IRSPS), Università degli studi 'G. d'Annunzio' Chieti-Pescara [Chieti-Pescara] (Ud'A), Istituto di Fisica dello Spazio Interplanetario (IFSI), Consiglio Nazionale delle Ricerche (CNR), Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Earth Sciences [London, ON], University of Western Ontario (UWO), Institute for Earth Observation [Bolzano], EURAC Research, Search for Extraterrestrial Intelligence Institute (SETI), ASP 2019, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), European Space Astronomy Centre (ESAC), European Space Agency (ESA), Smithsonian National Air and Space Museum, Smithsonian Institution, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Planetary Science Institute [Tucson] (PSI), Department of Physics [Moscow,USA], University of Idaho [Moscow, USA], Istituto di Ricerca per la Protezione Idrogeologica [Padova] (IRPI), Institute of Geophysics [Austin] (IG), University of Texas at Austin [Austin], Istituto di Radioastronomia (IRA), Dipartimento di Ingegneria Elettrica e delle Tecnologie dell'Informazione [Napoli] (DIETI), Università degli studi di Napoli Federico II, Cornell University [New York], Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], European Academy Bozen/Bolzano (EURAC), Stanford University, Royal Observatory of Belgium [Brussels] (ROB), Istituto di Radioastronomia [Bologna] (IRA), Lopes, R. M. C., Wall, S. D., Elachi, C., Birch, S. P. D., Corlies, P., Coustenis, A., Hayes, A. G., Hofgartner, J. D., Janssen, M. A., Kirk, R. L., Legall, A., Lorenz, R. D., Lunine, J. I., Malaska, M. J., Mastroguiseppe, M., Mitri, G., Neish, C. D., Notarnicola, C., Paganelli, F., Paillou, P., Poggiali, V., Radebaugh, J., Rodriguez, S., Schoenfeld, A., Soderblom, J. M., Solomonidou, A., Stofan, E. R., Stiles, B. W., Tosi, F., Turtle, E. P., West, R. D., Wood, C. A., Zebker, H. A., Barnes, J. W., Casarano, D., Encrenaz, P., Farr, T., Grima, C., Hemingway, D., Karatekin, O., Lucas, A., Mitchell, K. L., Ori, G., Orosei, R., Ries, P., Riccio, D., Soderblom, L. A., Zhang, Z., ITA, USA, FRA, and Hôpital Nord [CHU - APHM]-Assistance Publique - Hôpitaux de Marseille (APHM)-Aix Marseille Université (AMU)
- Subjects
Exploration of Saturn ,010504 meteorology & atmospheric sciences ,[SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] ,[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] ,01 natural sciences ,Liquid methane ,law.invention ,Astrobiology ,symbols.namesake ,[SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology ,law ,0103 physical sciences ,[SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology ,Radar ,Enceladus ,[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment ,010303 astronomy & astrophysics ,ComputingMilieux_MISCELLANEOUS ,0105 earth and related environmental sciences ,[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] ,Astronomy and Astrophysics ,Cassini ,radar ,Titan ,Planetary science ,13. Climate action ,Space and Planetary Science ,symbols ,Titan (rocket family) ,Geology - Abstract
International audience; Titan was a mostly unknown world prior to the Cassini spacecraft’s arrival in July 2004. We review the major scientific advances made by Cassini’s Titan Radar Mapper (RADAR) during 13 years of Cassini’s exploration of Saturn and its moons. RADAR measurements revealed Titan’s surface geology, observed lakes and seas of mostly liquid methane in the polar regions, measured the depth of several lakes and seas, detected temporal changes on its surface, and provided key evidence that Titan contains an interior ocean. As a result of the Cassini mission, Titan has gone from an uncharted world to one that exhibits a variety of Earth-like geologic processes and surface-atmosphere interactions. Titan has also joined the ranks of “ocean worlds” along with Enceladus and Europa, which are prime targets for astrobiological research.
- Published
- 2019
47. Titan’s 'Magic Islands': Transient features in a hydrocarbon sea
- Author
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Ralph D. Lorenz, Jason M. Soderblom, Claudia Notarnicola, Marco Mastrogiuseppe, Jonathan I. Lunine, Alexander G. Hayes, Jason D. Hofgartner, Michael Malaska, and Howard A. Zebker
- Subjects
Sea level change ,geological processes ,010504 meteorology & atmospheric sciences ,radar observations ,Titan ,Ephemeral key ,Astronomy and Astrophysics ,01 natural sciences ,Seafloor spreading ,Astrobiology ,Radar observations ,symbols.namesake ,Space and Planetary Science ,0103 physical sciences ,symbols ,Titan (rocket family) ,010303 astronomy & astrophysics ,Geology ,0105 earth and related environmental sciences - Abstract
The region of Titan’s hydrocarbon sea, Ligeia Mare, where transient bright features were previously discovered, was anomalously bright in the first of two more recent Cassini RADAR observations but not the second. Another transient bright feature in a different region of Ligeia Mare was also discovered in the first of the new observations. Here we present all the high-resolution observations of the regions containing these transient features and the quantitative constraints that we derived from them. We argue that these features are unlikely to be SAR image artifacts or permanent geophysical structures and thus their appearance is the result of ephemeral phenomena on Titan. We find that the transient features are more consistent with floating and/or suspended solids, bubbles, and waves than tides, sea level change, or seafloor change and based on the frequency of these phenomena in terrestrial settings, we consider waves to be the most probable hypothesis. These transient features are the first instance of active processes in Titan’s lakes and seas to be confirmed by multiple detections and demonstrate that Titan’s seas are not stagnant but rather dynamic environments.
- Published
- 2016
48. Constraining the physical properties of Titan’s empty lake basins using nadir and off-nadir Cassini RADAR backscatter
- Author
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Howard A. Zebker, Marco Mastrogiuseppe, Michael Malaska, Alexander G. Hayes, Tom G. Farr, R. J. Michaelides, J. Mullen, and Valerio Poggiali
- Subjects
Synthetic aperture radar ,010504 meteorology & atmospheric sciences ,hydrology ,Terrain ,Titan ,Titan, surface ,Titan, hydrology ,radar observations ,Structural basin ,01 natural sciences ,Physics::Geophysics ,symbols.namesake ,Radar backscatter ,0103 physical sciences ,surface ,Altimeter ,010303 astronomy & astrophysics ,Geomorphology ,Physics::Atmospheric and Oceanic Physics ,0105 earth and related environmental sciences ,Remote sensing ,Scattering ,Astronomy and Astrophysics ,Space and Planetary Science ,symbols ,Sedimentary rock ,Titan (rocket family) ,Geology - Abstract
We use repeat synthetic aperture radar (SAR) observations and complementary altimetry passes acquired by the Cassini spacecraft to study the scattering properties of Titan’s empty lake basins. The best-fit coefficients from fitting SAR data to a quasi-specular plus diffuse backscatter model suggest that the bright basin floors have a higher dielectric constant, but similar facet-scale rms surface facet slopes, to surrounding terrain. Waveform analysis of altimetry returns reveals that nadir backscatter returns from basin floors are greater than nadir backscatter returns from basin surroundings and have narrower pulse widths. This suggests that floor deposits are structurally distinct from their surroundings, consistent with the interpretation that some of these basins may be filled with evaporitic and/or sedimentary deposits. Basin floor deposits also express a larger diffuse component to their backscatter, which is likely due to variations in subsurface structure or an increase in roughness at the wavelength scale (Hayes, A.G. et al. [2008]. Geophys. Res. Lett. 35, 9). We generate a high-resolution altimetry radargram of the T30 altimetry pass over an empty lake basin, with which we place geometric constraints on the basin’s slopes, rim heights, and depth. Finally, the importance of these backscatter observations and geometric measurements for basin formation mechanisms is briefly discussed.
- Published
- 2016
49. Material transport map of Titan: The fate of dunes
- Author
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Jani Radebaugh, Elizabeth P. Turtle, Rosaly M. C. Lopes, Michael Malaska, Alexander G. Hayes, and Ralph D. Lorenz
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geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Equator ,Fluvial ,Astronomy and Astrophysics ,Terrain ,Atmospheric sciences ,01 natural sciences ,Sink (geography) ,Latitude ,symbols.namesake ,Space and Planetary Science ,0103 physical sciences ,symbols ,Polar ,Aeolian processes ,Titan (rocket family) ,010303 astronomy & astrophysics ,Geomorphology ,Geology ,0105 earth and related environmental sciences - Abstract
Using SAR data from Cassini’s RADAR instrument, we examined the orientations of three terrain units on Titan, bright lineated plains, streak-like plains, and linear dunes. From the overall integrated pattern of their orientation, we were able to determine Titan’s global material transport vectors. The analysis indicates that, in both the northern and southern hemispheres, materials from 0 to 35 deg latitude are transported poleward to a belt centred at roughly 35 deg. Materials from 60 to 35 deg latitude are transported equatorward to the belt at roughly 35 deg. Comparison with the global topographical gradient (Lorenz, R.D. et al. [2013]. Icarus 225, 367–377) suggests that fluvial transport is not the dominant process for material transport on Titan, or that it is at least overprinted with another transport mechanism. Our results are consistent with aeolian transport being the dominant mechanism in the equatorial and mid-latitude zones. The zone at 35 deg is thus the ultimate sink for materials from the equator to low polar latitudes; materials making up the equatorial dunes will be transported to the latitude 35-deg belts. Only plains units are observed at latitudes of ∼35 deg; dunes and materials with the spectral characteristics of dunes are not observed at these latitudes. This observation suggests that either dune materials are converted or modified into plains units or that the margins of dunes are transport limited.
- Published
- 2016
50. Nature, distribution, and origin of Titan’s Undifferentiated Plains
- Author
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Alexander G. Hayes, Kenneth J. Lawrence, Athena Coustenis, Michael Malaska, A. Le Gall, M. A. Janssen, A. Solomonidou, Ellen R. Stofan, Samuel Birch, Jani Radebaugh, Bryan Stiles, Catherine D. Neish, R. L. Kirk, Elizabeth P. Turtle, K. L. Mitchell, Ashley Schoenfeld, Rosaly M. C. Lopes, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Physics and Space Sciences [FIT], Florida Institute of Technology [Melbourne], Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Department of Astronomy [Ithaca], Cornell University [New York], Department of Geological Sciences [BYU], Brigham Young University (BYU), Astrogeology Science Center [Flagstaff], United States Geological Survey [Reston] (USGS), Department of Earth and Planetary Sciences [UCL/Birkbeck], Birkbeck College [University of London], and California Institute of Technology (CALTECH)-NASA
- Subjects
Synthetic aperture radar ,010504 meteorology & atmospheric sciences ,[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] ,Fluvial ,01 natural sciences ,Astrobiology ,law.invention ,Sedimentary depositional environment ,Paleontology ,symbols.namesake ,Impact crater ,law ,0103 physical sciences ,Radar ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences ,Astronomy and Astrophysics ,15. Life on land ,Radar observations ,[SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM] ,13. Climate action ,Space and Planetary Science ,symbols ,Aeolian processes ,Cassini ,Sedimentary rock ,Geological processes ,Titan ,Titan (rocket family) ,Geology - Abstract
The Undifferentiated Plains on Titan, first mapped by Lopes et al. (Lopes, R.M.C. et al., 2010. Icarus, 205, 540–588), are vast expanses of terrains that appear radar-dark and fairly uniform in Cassini Synthetic Aperture Radar (SAR) images. As a result, these terrains are often referred to as “blandlands”. While the interpretation of several other geologic units on Titan – such as dunes, lakes, and well-preserved impact craters – has been relatively straightforward, the origin of the Undifferentiated Plains has remained elusive. SAR images show that these “blandlands” are mostly found at mid-latitudes and appear relatively featureless at radar wavelengths, with no major topographic features. Their gradational boundaries and paucity of recognizable features in SAR data make geologic interpretation particularly challenging. We have mapped the distribution of these terrains using SAR swaths up to flyby T92 (July 2013), which cover >50% of Titan’s surface. We compared SAR images with other data sets where available, including topography derived from the SARTopo method and stereo DEMs, the response from RADAR radiometry, hyperspectral imaging data from Cassini’s Visual and Infrared Mapping Spectrometer (VIMS), and near infrared imaging from the Imaging Science Subsystem (ISS). We examined and evaluated different formation mechanisms, including (i) cryovolcanic origin, consisting of overlapping flows of low relief or (ii) sedimentary origins, resulting from fluvial/lacustrine or aeolian deposition, or accumulation of photolysis products created in the atmosphere. Our analysis indicates that the Undifferentiated Plains unit is consistent with a composition predominantly containing organic rather than icy materials and formed by depositional and/or sedimentary processes. We conclude that aeolian processes played a major part in the formation of the Undifferentiated Plains; however, other processes (fluvial, deposition of photolysis products) are likely to have contributed, possibly in differing proportions depending on location.
- Published
- 2016
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