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23 results on '"California Institute of Technology - Caltech (USA)"'

1. Seasonal variations of subsurface seismic velocities monitored by the SEIS-InSight seismometer on Mars

Author

N Compaire, L Margerin, M Monnereau, R F Garcia, L Lange, M Calvet, N L Dahmen, S C Stähler, N Mueller, M Grott, P Lognonné, T Spohn, W B Banerdt, Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), ANR-19-CE31-0008,MAGIS,MArs Geophysical InSight(2019), Centre National d'Études Spatiales - CNES (FRANCE), Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut de Physique du Globe de Paris - IPGP (FRANCE), Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), Institut de Recherche pour le Développement - IRD (FRANCE), Sorbonne Université (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), California Institute of Technology - Caltech (USA), Ecole Normale Supérieure de Paris - ENS Paris (FRANCE), Ecole Polytechnique (FRANCE), German Aerospace Center - DLR (GERMANY), Institut national des sciences de l'Univers - INSU (FRANCE), Eidgenössische Technische Hochschule Zürich - ETHZ (SWITZERLAND), Université Paris Sciences & Lettres - PSL (FRANCE), and Ecole des Ponts ParisTech (FRANCE)

Subjects
Geophysics, Autre, Seismic noise, Geochemistry and Petrology, Coda waves, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], seasonality, Seismic interferometry, Planetary interiors, Seismic interferometry – Seismic noise – Coda waves – Planetary interiors, Seismology
Abstract

SUMMARY The SEIS (Seismic Experiment for Interior Structure) seismometer deployed at the surface of Mars in the framework of the NASA-InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission has been continuously recording the ground motion at Elysium Planitia for more than one martian year. In this work, we investigate the seasonal variation of the near-surface properties using both background vibrations and a particular class of high-frequency seismic events. We present measurements of relative velocity changes over one martian year and show that they can be modelled by a thermoelastic response of the Martian regolith. Several families of high-frequency seismic multiplets have been observed at various periods of the martian year. These events exhibit complex, repeatable waveforms with an emergent character and a coda that is likely composed of scattered waves. Taking advantage of these properties, we use coda wave interferometry (CWI) to measure relative traveltime changes as a function of the date of occurrence of the quakes. While in some families a stretching of the coda waveform is clearly observed, in other families we observe either no variation or a clear contraction of the waveform. These various behaviors correspond to different conditions of illumination at the InSight landing site, depending on the season. Measurements of velocity changes from the analysis of background vibrations above 5 Hz are consistent with the results from CWI. We identify a frequency band structure in the power spectral density (PSD) that can be tracked over hundreds of days. This band structure is the equivalent in the frequency domain of an autocorrelogram and can be efficiently used to measure relative traveltime changes as a function of frequency. We explain how the PSD analysis allows us to circumvent the contamination of the measurements by the Lander mode excitation which is inevitable in the time domain. The observed velocity changes can be adequately modelled by the thermoelastic response of the regolith to the time-dependent incident solar flux at the seasonal scale. In particular, the model captures the time delay between the surface temperature variations and the velocity changes in the subsurface. Our observations could serve as a basis for a joint inversion of the seismic and thermal properties in the first 20 m below InSight.

Published
2022
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2. Seismic detection of the martian core

Author

Henri Samuel, Cedric Schmelzbach, Raphaël F. Garcia, Philippe Lognonné, Eléonore Stutzmann, Clément Perrin, Suzanne E. Smrekar, Paul M. Davis, Vedran Lekic, A. Cecilia Duran, Constantinos Charalambous, Taichi Kawamura, Simon Stähler, David Sollberger, Mélanie Drilleau, Anna Horleston, Ana-Catalina Plesa, Martin Schimmel, Ross Maguire, Martin Knapmeyer, Nicholas Schmerr, Mark P. Panning, Savas Ceylan, Do-Yeon Kim, Angela G. Marusiak, W. Bruce Banerdt, Matthieu Plasman, Eric Beucler, John Clinton, Géraldine Zenhäusern, Zongbo Xu, Amir Khan, Nikolaj Dahmen, Attilio Rivoldini, Martin van Driel, Tamara Gudkova, Domenico Giardini, Jessica C. E. Irving, Quancheng Huang, W. Thomas Pike, Daniele Antonangeli, Centre National de la Recherche Scientifique - CNRS (FRANCE), Consejo Superior de Investigaciones Científicas - CSIC (SPAIN), Institut de Physique du Globe de Paris - IPGP (FRANCE), Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), Institut de Recherche pour le Développement - IRD (FRANCE), Sorbonne Université (FRANCE), Université de Nantes (FRANCE), University of Bristol (UNITED KINGDOM), University of Maryland (USA), California Institute of Technology - Caltech (USA), DLR Institute of Planetary Research (GERMANY), Imperial College London (UNITED KINGDOM), Museum National d'Histoire Naturelle - MNHN (FRANCE), Royal Observatory of Belgium (BELGIUM), Russian academy of sciences (RUSSIA), Eidgenössische Technische Hochschule Zürich - ETHZ (SWITZERLAND), Université d'Angers (FRANCE), University of California-Los Angeles - UCLA (USA), Universität Zürich - UZH (SWITZERLAND), Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP), 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), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), ANR-19-CE31-0008,MAGIS,MArs Geophysical InSight(2019), NASA Jet Propulsion Laboratory, European Commission, Agence Nationale de la Recherche (France), Belgian Science Policy Office, European Space Agency, Ministerio de Ciencia, Innovación y Universidades (España), UK Space Agency, and 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)

Subjects
Martian, Multidisciplinary, 010504 meteorology & atmospheric sciences, Martian Core, Mars, Mars Exploration Program, Radius, Geophysics, 010502 geochemistry & geophysics, 01 natural sciences, Mantle (geology), Seismic wave, Planétologie, Core (optical fiber), [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, 13. Climate action, Planet, Transition zone, Seismic data, Mars seismology, Geology, 0105 earth and related environmental sciences, InSight
Abstract

Clues to a planet’s geologic history are contained in its interior structure, particularly its core. We detected reflections of seismic waves from the core-mantle boundary of Mars using InSight seismic data and inverted these together with geodetic data to constrain the radius of the liquid metal core to 1830 ± 40 kilometers. The large core implies a martian mantle mineralogically similar to the terrestrial upper mantle and transition zone but differing from Earth by not having a bridgmanite-dominated lower mantle. We inferred a mean core density of 5.7 to 6.3 grams per cubic centimeter, which requires a substantial complement of light elements dissolved in the iron-nickel core. The seismic core shadow as seen from InSight’s location covers half the surface of Mars, including the majority of potentially active regions—e.g., Tharsis—possibly limiting the number of detectable marsquakes., Science, 373 (6553), ISSN:0036-8075, ISSN:1095-9203

Published
2021
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3. An empirical correlation between lift and the properties of leading-edge vortices

Author

Jeesoon Choi, Thierry Jardin, Tim Colonius, Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), and California Institute of Technology - Caltech (USA)

Subjects
Fluid Flow and Transfer Processes, Physics, Airfoil, Leading edge, Mécanique des fluides, Flow (psychology), General Engineering, Computational Mechanics, Mechanics, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas, Vortex, Physics::Fluid Dynamics, Lift (force), Circulation (fluid dynamics), Position (vector), Low order models, Surging wings, 0103 physical sciences, Trailing edge, 010306 general physics, Leading edge vortex
Abstract

Using data from numerical simulations, we show that the lift experienced by both impulsively started and surging airfoils correlates well with the sum of the circulation of the leading-edge vortices truncated at the trailing edge. Therefore, we suggest that reasonable estimates of the lift can be obtained using only two vortex parameters, i.e., its circulation and its position. In addition to being convenient for non-intrusive estimation of forces from PIV measurements, we show that this approach can be used to derive low-order models for the analysis of vortex-lift configurations. In particular, we apply this correlation to model high-amplitude surging, which allows us to quantify the effect of wake-capture mechanisms and to determine the flow parameters that drive optimal lift.

Published
2021
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4. Constraining Martian Regolith and Vortex Parameters From Combined Seismic and Meteorological Measurements

Author

Aymeric Spiga, William B. Banerdt, Ralph D. Lorenz, Naomi Murdoch, C. Perrin, R. Widmer-Schnidrig, Sebastien Rodriguez, David Mimoun, Nicolas Compaire, Nicholas H. Warner, Philippe Lognonné, Raphaël F. Garcia, Don Banfield, Cornell University (USA), Institut de Physique du Globe de Paris - IPGP (FRANCE), Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), Institut universitaire de France - IUF (FRANCE), Karlsruhe Institute of Technology - KIT (GERMANY), Université Paris Sciences & Lettres - PSL (FRANCE), Universität Karlsruhe (GERMANY), Universität Stuttgart (GERMANY), Johns Hopkins Applied Physics Laboratory - APL (USA), California Institute of Technology - Caltech (USA), Ecole Normale Supérieure de Paris - ENS Paris (FRANCE), State University of New York - SUNY (USA), Département Electronique, Optronique et Signal (DEOS), Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), 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), Universität Stuttgart [Stuttgart], State University of New York (SUNY), Cornell Center for Astrophysics and Planetary Science (CCAPS), Cornell University [New York], Jet Propulsion Laboratory (JPL), and NASA-California Institute of Technology (CALTECH)

Subjects
Convection, Seismometer, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], 01 natural sciences, Regolith, law.invention, Physics::Geophysics, Autre, Mars atmosphere, Geochemistry and Petrology, law, Earth and Planetary Sciences (miscellaneous), Dust devil, 0105 earth and related environmental sciences, InSight, Dust devils, Martian, Neurosciences, Mars Exploration Program, Geophysics, Vortices, Vortex, Barometer, Space and Planetary Science, Elastic, Astrophysics::Earth and Planetary Astrophysics, Geology
Abstract

International audience; The InSight mission landed on Mars in November 2018 and has since observed multiple convective vortices with both the high performance barometer and the low-noise seismometer SEIS that has unprecedented sensitivity. Here, we present a new method that uses the simultaneous pressure and seismic measurements of convective vortices to place constraints on the elastic properties of the Martian subsurface and the Martian vortex properties, while also allowing a reconstruction of the convective vortex trajectories. From data filtered in the (0.02–0.3 Hz) frequency band, we estimate that the mean value of η (η = E/[1 − ν2], where E is the Young's modulus and ν is the Poisson's ratio) of the Martian ground in the region around SEIS is 239 ± 140 MPa. In addition, we suggest that the previously reported paucity of vortex seismic observations to the west of InSight may be due to the fact that the ground is harder to the west than to the east, consistent with geomorphological surface interpretations.

Published
2021
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5. Preparing for InSight: An Invitation to Participate in a Blind Test for Martian Seismicity

Author

Mark P. Panning, M. van Driel, Naomi Murdoch, Philippe Lognonné, David Mimoun, B. Kenda, L. Perrin, Bruce Banerdt, Ingrid Daubar, Matthew P. Golombek, John Clinton, Jeroen Tromp, Mélanie Drilleau, Aymeric Spiga, Savas Ceylan, Maren Böse, Raphaël F. Garcia, Renee Weber, Amir Khan, Domenico Giardini, Centre National d'Études Spatiales - CNES (FRANCE), Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), National Aeronautics and Space Administration - NASA (USA), Université de Paris Diderot - Paris 7 (FRANCE), Sorbonne Université (FRANCE), University of Florida (USA), California Institute of Technology - Caltech (USA), Princeton University (USA), and Eidgenössische Technische Hochschule Zürich - ETHZ (SWITZERLAND)

Subjects
Martian, 010504 meteorology & atmospheric sciences, Team plan, Seismicity, Mars, Single station, Mars Exploration Program, Induced seismicity, 01 natural sciences, Test (assessment), InSight seismology geophysics noise Mars, Geophysics, Autre, 13. Climate action, 0103 physical sciences, Insight, Routine analysis, 010303 astronomy & astrophysics, Astrophysique, Geology, Seismology, 0105 earth and related environmental sciences
Abstract

The InSight (Interior exploration using Seismic Investigations, Geodesy and Heat Transport) lander will deploy a seismic monitoring package on Mars in November 2018. In prepara- tion for the data return, we prepared a blind test in which we invite participants to detect and characterize seismicity included in a synthetic dataset of continuous waveforms from a single station that mimics both the streams of data that will be available from InSight, as well as expected tectonic and impact seismicity and noise conditions on Mars. We expect that the test will ultimately improve and extend the current set of methods that the InSight team plan to use in routine analysis of the Martian dataset.

Published
2017
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6. Aero Maneuvering Dynamics and Control for Precision Landing on Titan

Author

Jasmine Rimani, Luca Ermolli, Marco B. Quadrelli, Aaron Schutte, and California Institute of Technology - Caltech (USA)

Subjects
0209 industrial biotechnology, Titan simulation, Wind models, 02 engineering and technology, computer.software_genre, Titan environmental parameters, 01 natural sciences, symbols.namesake, 020901 industrial engineering & automation, Autre, 0103 physical sciences, Autonomous parafoil, Aerospace engineering, Adverse wind environment, Extrapolated wind gust models, 010303 astronomy & astrophysics, Precision landing, Martian, business.industry, Controller performance, Relative dynamics, Software framework, Dynamic models, Point mass models, Wind magnitude, Wind gust, Control techniques, symbols, Environmental science, Titan (rocket family), business, computer, Rigid multibody models
Abstract

We have developed and tested several dynamic models of the parafoil system descending in Titan's atmosphere. These dynamic models include a progression from point mass models to rigid multibody models, including relative dynamics between canopy and payload. In these models, we have included wind models used for Titan simulation, and extrapolated wind gust models previously used for simulation in the Martian environment. We have also developed guidance and control techniques for autonomous parafoil turning in the adverse wind environment. Finally, and in order to improve the controller performance by reducing the uncertainty to environmental factors, we have also developed ways to estimate the Titan environmental parameters, i.e. the atmospheric density, and the wind magnitude, during the descent. A more complete and realistic simulation is being developed, which uses JPL's DSENDS Entry, Descent, and Landing Software framework.

Published
2019

7. Numerical Simulation of the Atmospheric Signature of Artificial and Natural Seismic Events

Author

L. Martire, Roland Martin, Attila Komjathy, Voon Hui Lai, Alexandre Cadu, Quentin Brissaud, James A. Cutts, Jennifer M. Jackson, Raphaël F. Garcia, Anthony Sournac, David Mimoun, Siddharth Krishnamoorthy, Michael Pauken, Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), Institut de Recherche pour le Développement - IRD (FRANCE), National Aeronautics and Space Administration - NASA (USA), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), California Institute of Technology - Caltech (USA), Jet Propulsion Laboratory - JPL (Pasadena, USA), Département Electronique, Optronique et Signal (DEOS), Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), California Institute of Technology (CALTECH), Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, Infrasound, Ingénierie de l'environnement, Numerical simulation, 010502 geochemistry & geophysics, 01 natural sciences, Physics::Geophysics, Atmosphere, Autre, Passive seismic, Infrasound Balloon Solid/atmosphere coupling Numerical simulations, 0105 earth and related environmental sciences, Seismic event detection, Computer simulation, Plane (geometry), Active seismic experiment, Acoustic wave, Geophysics, Amplitude, Passive seismic experiment, Surface wave, Ground imaging, General Earth and Planetary Sciences, [SDU.OTHER]Sciences of the Universe [physics]/Other, Geology, Seismology
Abstract

International audience; The mechanical coupling between solid planets and their atmospheres enables seismically induced acoustic waves to propagate in the atmosphere. We numerically simulate this coupled system for two application cases: active seismic experiments (ASEs) and passive seismic experiments. A recent ASE (Krishnamoorthy et al., 2018, https://doi.org/10.1002/2018GL077481) observed the infrasonic signals produced by a seismic hammer. To measure the sensitivity of observations to seismic parameters, we attempt to reproduce the results from this experiment at short range by considering a realistic unconsolidated subsurface and an idealized rock-solid subsurface. At long range, we investigate the influence of the source by using two focal mechanisms. We found surface waves generate an infrasonic plane head wave in the ASE case of the rock-solid material. For the passive seismic experiments, the amplitude of atmospheric infrasound generated by seismic surface waves is investigated in detail. Despite some limitations, the simulations suggest that balloon measurement of seismically induced infrasound might help to constrain ground properties.

Published
2018
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8. Influence of body waves, instrumentation resonances, and prior assumptions on Rayleigh wave ellipticity inversion for shallow structure at the InSight landing site

Author

Martin Knapmeyer, Balthasar Kenda, William B. Banerdt, Philippe Lognonné, Sharon Kedar, Lars Witte, Naomi Murdoch, Matthew P. Golombek, Nicolas Verdier, Brigitte Knapmeyer-Endrun, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Département Electronique, Optronique et Signal (DEOS), Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Institut de Physique du Globe de Paris (IPGP), 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), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), DLR Institute of Planetary Research, German Aerospace Center (DLR), DLR Institute of Space Systems, Centre National d'Études Spatiales [Toulouse] (CNES), Centre National d'Études Spatiales - CNES (FRANCE), Institut de Physique du Globe de Paris - IPGP (FRANCE), Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), Max Planck Society (GERMANY), California Institute of Technology - Caltech (USA), DLR Institute of Planetary Research (GERMANY), DLR Institute of Space Systems (GERMANY), Département d'Electronique, Optronique et Signal - DEOS (Toulouse, France), and Jet Propulsion Laboratory - JPL (Pasadena, USA)

Subjects
[SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Mars, Seismic noise, 010502 geochemistry & geophysics, 01 natural sciences, 7. Clean energy, Regolith, Spectral line, symbols.namesake, Interior, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, 0103 physical sciences, Rayleigh wave, Rayleigh waves, Automatique / Robotique, 010303 astronomy & astrophysics, Scaling, Seismology, 0105 earth and related environmental sciences, InSight, Levelling, Astronomy and Astrophysics, Mars Exploration Program, Computational physics, Amplitude, Space and Planetary Science, symbols, Rayleigh Waves, Geology
Abstract

International audience; Based on an updated model of the regolith’s elastic properties, we simulate the ambient vibrations background wavefield recorded by InSight’s Seismic Experiment for Interior Structure (SEIS) on Mars to characterise the influence of the regolith and invert SEIS data for shallow subsurface structure. By approximately scaling the synthetics based on seismic signals of a terrestrial dust devil, we find that the high-frequency atmospheric background wavefield should be above the self-noise of SEIS’s SP sensors, even if the signals are not produced within 100–200 m of the station. We compare horizontal-to-vertical spectral ratios and Rayleigh wave ellipticity curves for a surface-wave based simulation on the one hand with synthetics explicitly considering body waves on the other hand and do not find any striking differences. Inverting the data, we find that the results are insensitive to assumptions on density. By contrast, assumptions on the velocity range in the upper-most layer have a strong influence on the results also at larger depth. Wrong assumptions can lead to results far from the true model in this case. Additional information on the general shape of the curve, i.e. single or dual peak, could help to mitigate this effect, even if it cannot directly be included into the inversion. We find that the ellipticity curves can provide stronger constraints on the minimum thickness and velocity of the second layer of the model than on the maximum values. We also consider the effect of instrumentation resonances caused by the lander flexible modes, solar panels, and the SEIS levelling system. Both the levelling system resonances and the lander flexible modes occur at significantly higher frequencies than the expected structural response, i.e. above 35 Hz and 20 Hz, respectively. While the lander and solar panel resonances might be too weak in amplitude to be recorded by SEIS, the levelling system resonances will show up clearly in horizontal spectra, the H/V and ellipticity curves. They are not removed by trying to extract only Rayleigh-wave dominated parts of the data. However, they can be distinguished from any subsurface response by their exceptionally low damping ratios of 1% or less as determined by random decrement analysis. The same applies to lander-generated signals observed in actual data from a Moon analogue experiment, so we expect this analysis will be useful in identifying instrumentation resonances in SEIS data.

Published
2018
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9. Detection of Artificially Generated Seismic Signals Using Balloon-Borne Infrasound Sensors

Author

Jennifer M. Jackson, Raphaël F. Garcia, Siddharth Krishnamoorthy, Michael Pauken, Voon Hui Lai, Daniel C. Bowman, James A. Cutts, Attila Komjathy, David Mimoun, Alexandre Cadu, Anthony Sournac, Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), National Aeronautics and Space Administration - NASA (USA), California Institute of Technology - Caltech (USA), and Sandia (USA)

Subjects
Signal processing, 010504 meteorology & atmospheric sciences, biology, Infrasound, Venus, 010502 geochemistry & geophysics, biology.organism_classification, Balloon, 01 natural sciences, Barometer, law.invention, Troposphere, Geophysics, Wind noise, Autre, law, General Earth and Planetary Sciences, Acoustic signature, Traitement du signal et de l'image, Infrasound Balloon, Geology, 0105 earth and related environmental sciences, Remote sensing
Abstract

We conducted an experiment in Pahrump, Nevada, in June 2017, where artificial seismic signals were created using a seismic hammer, and the possibility of detecting them from their acoustic signature was examined. In this work, we analyze the pressure signals recorded by highly sensitive barometers deployed on the ground and on tethers suspended from balloons. Our signal processing results show that wind noise experienced by a barometer on a free-flying balloon is lower compared to one on a moored balloon. This has never been experimentally demonstrated in the lower troposphere. While seismoacoustic signals were not recorded on the hot air balloon platform owing to operational challenges, we demonstrate the detection of seismoacoustic signals on our moored balloon platform. Our results have important implications for performing seismology in harsh surface environments such as Venus through atmospheric remote sensing.

Published
2018

10. On the lift-optimal aspect ratio of a revolving wing at low Reynolds number

Author

Thierry Jardin, Tim Colonius, Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), and California Institute of Technology - Caltech (USA)

Subjects
Wing root, Lift coefficient, Insecta, Aspect ratio, Mécanique des fluides, Biomedical Engineering, Biophysics, Bioengineering, 01 natural sciences, Biochemistry, Models, Biological, 010305 fluids & plasmas, Biomaterials, Rossby number, Birds, symbols.namesake, Aerodynamics, 0103 physical sciences, Animals, Wings, Animal, Computer Simulation, 010306 general physics, Life Sciences–Engineering interface, Physics, Wing, Flapping and revolving wings, Reynolds number, Mechanics, Vortex, Lift (force), Vortex flows, Flight, Animal, symbols, Biotechnology
Abstract

Lentink & Dickinson (2009J. Exp. Biol.212, 2705–2719. (doi:10.1242/jeb.022269)) showed that rotational acceleration stabilized the leading-edge vortex on revolving, low aspect ratio (AR) wings and hypothesized that a Rossby number of around 3, which is achieved during each half-stroke for a variety of hovering insects, seeds and birds, represents a convergent high-lift solution across a range of scales in nature. Subsequent work has verified that, in particular, the Coriolis acceleration plays a key role in LEV stabilization. Implicit in these results is that there exists an optimal AR for wings revolving about their root, because it is otherwise unclear why, apart from possible morphological reasons, the convergent solution would not occur for an even lower Rossby number. We perform direct numerical simulations of the flow past revolving wings where we vary the AR and Rossby numbers independently by displacing the wing root from the axis of rotation. We show that the optimal lift coefficient represents a compromise between competing trends with competing time scales where the coefficient of lift increases monotonically with AR, holding Rossby number constant, but decreases monotonically with Rossby number, when holding AR constant. For wings revolving about their root, this favours wings of AR between 3 and 4.

Published
2017

11. Finite-Difference Modeling of Acoustic and Gravity Wave Propagation in Mars Atmosphere: Application to Infrasounds Emitted by Meteor Impacts

Author

Roland Martin, Bruce Banerdt, Quentin Brissaud, Aymeric Spiga, Philippe Lognonné, Lucie Rolland, Dimitri Komatitsch, Raphaël F. Garcia, Département Electronique, Optronique et Signal (DEOS), Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA), Géosciences Environnement Toulouse (GET), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Centre National d'Études Spatiales [Toulouse] (CNES), Laboratoire de Mécanique et d'Acoustique [Marseille] (LMA ), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), Institut de Physique du Globe de Paris (IPGP), 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), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Aix-Marseille Université - AMU (FRANCE), Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut de Physique du Globe de Paris - IPGP (FRANCE), Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), National Aeronautics and Space Administration - NASA (USA), Observatoire de la Côte d'Azur (FRANCE), Université Pierre et Marie Curie, Paris 6 - UPMC (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), California Institute of Technology - Caltech (USA), Ecole Centrale Marseille (FRANCE), Ecole Normale Supérieure de Paris - ENS Paris (FRANCE), Ecole Polytechnique (FRANCE), Ecole des Ponts ParisTech (FRANCE), Institut national des sciences de l'Univers - INSU (FRANCE), Géosciences Environnement Toulouse - GET (Toulouse, France), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), 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), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), and Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SPI.OTHER]Engineering Sciences [physics]/Other, 010504 meteorology & atmospheric sciences, Pressure sensor, Mars, Gravity waves, Atmospheric sciences, 01 natural sciences, Atmosphere, 0103 physical sciences, Numerical modeling, Traitement du signal et de l'image, Gravity wave, 010303 astronomy & astrophysics, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences, Physics, Martian, Attenuation, Astronomy and Astrophysics, Geophysics, Mars Exploration Program, Acoustic wave, Atmosphere of Mars, Ray tracing (physics), Acoustic waves, 13. Climate action, Space and Planetary Science, Impacts, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, InSight mission
Abstract

International audience; The propagation of acoustic and gravity waves in planetary atmospheres is strongly dependent on both wind conditions and attenuation properties. This study presents a finite-difference modeling tool tailored for acoustic-gravity wave applications that takes into account the effect of background winds, attenuation phenomena (including relaxation effects specific to carbon dioxide atmospheres) and wave amplification by exponential density decrease with height. The simulation tool is implemented in 2D Cartesian coordinates and first validated by comparison with analytical solutions for benchmark problems. It is then applied to surface explosions simulating meteor impacts on Mars in various Martian atmospheric conditions inferred from global climate models. The acoustic wave travel times are validated by comparison with 2D ray tracing in a windy atmosphere. Our simulations predict that acoustic waves generated by impacts can refract back to the surface on wind ducts at high altitude. In addition, due to the strong nighttime near-surface temperature gradient on Mars, the acoustic waves are trapped in a waveguide close to the surface, which allows a night-side detection of impacts at large distances in Mars plains. Such theoretical predictions are directly applicable to future measurements by the INSIGHT NASA Discovery mission.

Published
2017
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12. Bolide Airbursts as a Seismic Source for the 2018 Mars InSight Mission

Author

Nicholas A Teanby, Raphaël F. Garcia, Ingrid Daubar, Neil D. Selby, Jeremie Vaubaillon, Jennifer Stevanović, James Wookey, Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), National Aeronautics and Space Administration - NASA (USA), Sorbonne Université (FRANCE), University of Bristol (UNITED KINGDOM), California Institute of Technology - Caltech (USA), Institut national des sciences de l'Univers - INSU (FRANCE), Observatoire de Paris (FRANCE), Université de Lille (FRANCE), Jet Propulsion Laboratory - JPL (Pasadena, USA), School of Earth Sciences [Bristol], University of Bristol [Bristol], Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Airbursts, 010504 meteorology & atmospheric sciences, Meteors, Atmospheric processes, Population, Mars, 01 natural sciences, Astrobiology, Autre, Bolide, 0103 physical sciences, education, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Martian, education.field_of_study, Meteoroid, Astronomy and Astrophysics, Mars Exploration Program, Atmosphere of Mars, Radius, Planetary science, 13. Climate action, Space and Planetary Science, [SDU.OTHER]Sciences of the Universe [physics]/Other, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology
Abstract

In 2018, NASA will launch InSight, a single-station suite of geophysical instruments, designed to characterise the martian interior. We investigate the seismo-acoustic signal generated by a bolide entering the martian atmosphere and exploding in a terminal airburst, and assess this phenomenon as a potential observable for the SEIS seismic payload. Terrestrial analogue data from four recent events are used to identify diagnostic airburst characteristics in both the time and frequency domain. In order to estimate a potential number of detectable events for InSight, we first model the impactor source population from observations made on the Earth, scaled for planetary radius, entry velocity and source density. We go on to calculate a range of potential airbursts from the larger incident impactor population. We estimate there to be ${\sim}\,1000$ events of this nature per year on Mars. To then derive a detectable number of airbursts for InSight, we scale this number according to atmospheric attenuation, air-to-ground coupling inefficiencies and by instrument capability for SEIS. We predict between 10–200 detectable events per year for InSight.

Published
2017
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13. Immersed Boundary Lattice Green Function methods for External Aerodynamics

Author

Gianmarco Mengaldo, Thierry Jardin, Sebastian Liska, Ke Yu, Tim Colonius, Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), and California Institute of Technology - Caltech (USA)

Subjects
Mécanique des fluides, Mathematical analysis, 010103 numerical & computational mathematics, Aerodynamics, Immersed boundary method, 01 natural sciences, 010305 fluids & plasmas, Physics::Fluid Dynamics, Lattice Green Function, Lattice (order), 0103 physical sciences, Compressibility, 0101 mathematics, Mathematics
Abstract

In this paper, we document the capabilities of a novel numerical approach - the immersed boundary lattice Green's function (IBLGF) method - to simulate external incompressible flows over complex geometries. This new approach is built upon the immersed boundary method and lattice Green's functions to solve the incompressible Navier-Stokes equations. We show that the combination of these two concepts allows the construction of an efficient and robust numerical framework for the direct numerical and large-eddy simulation of external aerodynamic problems at moderate to high-Reynolds numbers.

Published
2017

14. Evaluating the Wind-Induced Mechanical Noise on the InSight Seismometers

Author

Philippe Lognonné, Naomi Murdoch, David Mimoun, Don Banfield, William B. Banerdt, Willian Rapin, Taichi Kawamuea, Raphaël F. Garcia, Centre National de la Recherche Scientifique - CNRS (FRANCE), Cornell University (USA), Institut de Physique du Globe de Paris - IPGP (FRANCE), Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), National Aeronautics and Space Administration - NASA (USA), Université de Paris Diderot - Paris 7 (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Université de La Réunion (FRANCE), California Institute of Technology - Caltech (USA), Institut national des sciences de l'Univers - INSU (FRANCE), Jet Propulsion Laboratory - JPL (Pasadena, USA), Département Electronique, Optronique et Signal (DEOS), Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP), 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), Cornell Center for Astrophysics and Planetary Science (CCAPS), Cornell University, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Cornell University [New York], Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SPI.OTHER]Engineering Sciences [physics]/Other, Seismometer, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Mars, 01 natural sciences, Regolith, Space exploration, Physics - Geophysics, Autre, 0103 physical sciences, Aerospace engineering, Baseline (configuration management), 010303 astronomy & astrophysics, Seismology, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Martian, business.industry, Atmosphere, Astronomy and Astrophysics, Mars Exploration Program, Mechanical noise, Geophysics (physics.geo-ph), Physics - Atmospheric and Oceanic Physics, Noise, Geophysics, Space and Planetary Science, Software deployment, Atmospheric and Oceanic Physics (physics.ao-ph), business, Geology, Astrophysics - Earth and Planetary Astrophysics
Abstract

The SEIS (Seismic Experiment for Interior Structures) instrument onboard the InSight mission to Mars is the critical instrument for determining the interior structure of Mars, the current level of tectonic activity and the meteorite flux. Meeting the performance requirements of the SEIS instrument is vital to successfully achieve these mission objectives. Here we analyse in-situ wind measurements from previous Mars space missions to understand the wind environment that we are likely to encounter on Mars, and then we use an elastic ground deformation model to evaluate the mechanical noise contributions on the SEIS instrument due to the interaction between the Martian winds and the InSight lander. Lander mechanical noise maps that will be used to select the best deployment site for SEIS once the InSight lander arrives on Mars are also presented. We find the lander mechanical noise may be a detectable signal on the InSight seismometers. However, for the baseline SEIS deployment position, the noise is expected to be below the total noise requirement >97% of the time and is, therefore, not expected to endanger the InSight mission objectives., 32 pages, 16 figures

Published
2017
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15. Estimations of the Seismic Pressure Noise on Mars Determined from Large Eddy Simulations and Demonstration of Pressure Decorrelation Techniques for the Insight Mission

Author

Taichi Kawamura, Balthasar Kenda, Philippe Lognonné, Aymeric Spiga, William B. Banerdt, Naomi Murdoch, David Mimoun, Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut de Physique du Globe de Paris - IPGP (FRANCE), Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), National Aeronautics and Space Administration - NASA (USA), Université de Paris Diderot - Paris 7 (FRANCE), Université Pierre et Marie Curie, Paris 6 - UPMC (FRANCE), Université de La Réunion (FRANCE), California Institute of Technology - Caltech (USA), Ecole Normale Supérieure de Paris - ENS Paris (FRANCE), Ecole Polytechnique (FRANCE), Ecole des Ponts ParisTech (FRANCE), Institut national des sciences de l'Univers - INSU (FRANCE), Département Electronique, Optronique et Signal (DEOS), Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), 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), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), 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), and École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris)

Subjects
Seismometer, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Mars, Surface pressure, 01 natural sciences, Regolith, Physics::Geophysics, Physics - Geophysics, 0103 physical sciences, Pressure, 010303 astronomy & astrophysics, Decorrelation, Astrophysique, Seismology, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Atmospheric pressure, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Atmosphere, Astronomy and Astrophysics, Mars Exploration Program, Geodesy, Pressure sensor, Geophysics (physics.geo-ph), Physics - Atmospheric and Oceanic Physics, Amplitude, Geophysics, 13. Climate action, Space and Planetary Science, Atmospheric and Oceanic Physics (physics.ao-ph), Geology, Noise (radio), Astrophysics - Earth and Planetary Astrophysics
Abstract

International audience; The atmospheric pressure fluctuations on Mars induce an elastic response in the ground that creates a ground tilt, detectable as a seismic signal on the InSight seismometer SEIS. The seismic pressure noise is modeled using Large Eddy Simulations (LES) of the wind and surface pressure at the InSight landing site and a Green’s function ground deformation approach that is subsequently validated via a detailed comparison with two other methods: a spectral approach, and an approach based on Sorrells’ theory (Sorrells,Geophys. J. Int. 26:71–82, 1971; Sorrells et al., Nat. Phys. Sci. 229:14–16, 1971). The horizontal accelerations as a result of the ground tilt due to the LES turbulence-induced pressure fluctuations are found to be typically ∼ 2–40 nm/s2 in amplitude, whereas the direct horizontal acceleration is two orders of magnitude smaller and is thus negligible in comparison. The vertical accelerations are found to be ∼ 0.1–6 nm/s2 in amplitude. These are expected to be worst-case estimates for the seismic noise as we use a half-space approximation; the presence at some (shallow) depth of a harder layer would significantly reduce quasi-static displacement and tilt effects. We show that under calm conditions, a single-pressure measurement is representative of the large-scale pressure field (to a distance of several kilometers), particularly in the prevailing wind direction. However, during windy conditions, small-scale turbulence results in a reduced correlation between the pressure signals, and the single-pressure measurement becomes less representative of the pressure field. The correlation between the seismic signal and the pressure signal is found to be higher for the windiest period because the seismic pressure noise reflects the atmospheric structure close to the seismometer. In the same way that we reduce the atmospheric seismic signal by making use of a pressure sensor that is part of the InSight Auxiliary Payload Sensor Suite, we also the use the synthetic noise data obtained from the LES pressure field to demonstrate a decorrelation strategy. We show that our decorrelation approach is efficient, resulting in a reduction by a factor of ∼ 5 in the observed horizontal tilt noise (in the wind direction) and the vertical noise. This technique can, therefore, be used to remove the pressure signal from the seismic data obtained on Mars during the InSight mission.

Published
2017
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16. The Noise Model of the SEIS Seismometer of the InSight Mission to Mars

Author

William B. Banerdt, Philippe Lognonné, Naomi Murdoch, David Mimoun, K. Hurst, William T. Pike, Jane Hurley, T. Nebut, Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut de Physique du Globe de Paris - IPGP (FRANCE), Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), National Aeronautics and Space Administration - NASA (USA), Université de Paris Diderot - Paris 7 (FRANCE), Université de La Réunion (FRANCE), California Institute of Technology - Caltech (USA), Imperial College London (UNITED KINGDOM), Institut national des sciences de l'Univers - INSU (FRANCE), and Science and Technology Facilities Council - STFC (UNITED KINGDOM)

Subjects
Seismometer, Operation planning, Martian, 010504 meteorology & atmospheric sciences, Noise model, Bandwidth (signal processing), Astronomy and Astrophysics, Mars Exploration Program, Seismic noise, 01 natural sciences, On board, InSight SEIS, Planetary science, Autre, 13. Climate action, Space and Planetary Science, 0103 physical sciences, 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences, Remote sensing, Mars environment
Abstract

The SEIS (Seismic Experiment for Interior Structures) instrument on board the InSight mission to Mars is the critical instrument for determining the interior structure of Mars, the current level of tectonic activity and the meteorite flux. Meeting the performance requirements of the SEIS instrument is vital to successfully achieve these mission objectives. The InSight noise model is a key tool for the InSight mission and SEIS instrument requirement setup. It will also be used for future operation planning. This paper presents the analyses made to build a model of the Martian seismic noise as measured by the SEIS seismometer, around the seismic bandwidth of the instrument (from 0.01 Hz to 1 Hz). It includes the instrument self-noise, but also the environment parameters that impact the measurements. We present the general approach for the model determination, the environment assumptions, and we analyze the major and minor contributors to the noise model.

Published
2017

17. Single-station and single-event marsquake location and inversion for structure using synthetic Martian waveforms

Author

Fabian Euchner, John Clinton, Naomi Murdoch, Savas Ceylan, David Mimoun, Martin Knapmeyer, Mark P. Panning, Maren Böse, Amir Khan, Philippe Lognonné, M. van Driel, William B. Banerdt, J Yan, Domenico Giardini, Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut de Physique du Globe de Paris - IPGP (FRANCE), Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), National Aeronautics and Space Administration - NASA (USA), Université de Paris Diderot - Paris 7 (FRANCE), Université de La Réunion (FRANCE), University of Florida (USA), California Institute of Technology - Caltech (USA), Deutsches Zentrum für Luft- und Raumfahrt - DLR (GERMANY), Institut national des sciences de l'Univers - INSU (FRANCE), Eidgenössische Technische Hochschule Zürich - ETHZ (SWITZERLAND), and Institut de Physique du Globe de Paris - IPGP (Paris, France)

Subjects
010504 meteorology & atmospheric sciences, Physics and Astronomy (miscellaneous), Spectral element method, Mars, Interior structure, 010502 geochemistry & geophysics, 01 natural sciences, Physics::Geophysics, symbols.namesake, Travel times, Martian surface, Surface-wave overtones, Rayleigh wave, Waveforms, Seismogram, 0105 earth and related environmental sciences, Marsquakes, Martian, Attenuation, Inversion, Astronomy and Astrophysics, Mars Exploration Program, Geodesy, Surface waves, Geophysics, Space and Planetary Science, Surface wave, symbols, Géophysique, Body-waves, Geology, Seismology
Abstract

In anticipation of the upcoming InSight mission, which is expected to deploy a single seismic station on the Martian surface in November 2018, we describe a methodology that enables locating marsquakes and obtaining information on the interior structure of Mars. The method works sequentially and is illustrated using single representative 3-component seismograms from two separate events: a relatively large teleseismic event (Mw5.1) and a small-to-moderate-sized regional event (Mw3.8). Location and origin time of the event is determined probabilistically from observations of Rayleigh waves and body-wave arrivals. From the recording of surface waves, averaged fundamental-mode group velocity dispersion data can be extracted and, in combination with body-wave arrival picks, inverted for crust and mantle structure. In the absence of Martian seismic data, we performed full waveform computations using a spectral element method (AxiSEM) to compute seismograms down to a period of 1 s. The model (radial profiles of density, P- and S-wave-speed, and attenuation) used for this purpose is constructed on the basis of an average Martian mantle composition and model areotherm using thermodynamic principles, mineral physics data, and viscoelastic modeling. Noise was added to the synthetic seismic data using an up-to-date noise model that considers a whole series of possible noise sources generated in instrument and lander, including wind-, thermal-, and pressure-induced effects and electromagnetic noise. The examples studied here, which are based on the assumption of spherical symmetry, show that we are able to determine epicentral distance and origin time to accuracies of ∼ 0.5–1° and ± 3–6 s, respectively. For the events and the particular noise level chosen, information on Rayleigh-wave group velocity dispersion in the period range ∼ 14–48 s (Mw5.1) and ∼ 14–34 s (Mw3.8) could be determined. Stochastic inversion of dispersion data in combination with body-wave travel time information for interior structure, allows us to constrain mantle velocity structure to an uncertainty of ∼ 5%. Employing the travel times obtained with the initially inverted models, we are able to locate additional body-wave arrivals including depth phases, surface and Moho (multiple) reflections that may otherwise elude visual identification. This expanded data set is reinverted to refine interior structure models and source parameters (epicentral distance and origin time).

Published
2016

18. High-Temperature Transport Properties of Yb4−x Sm x Sb3

Author

Audrey Chamoire, Claude Estournès, Franck Gascoin, Jean-Claude Tedenac, Thierry Caillat, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Centre interuniversitaire de recherche et d'ingenierie des matériaux (CIRIMAT), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC), ANR-06-JCJC-0090,THERMEL,Nouveaux Matériaux Thermoélectriques: antimoniures et tellurures du type structural Th3P4(2006), Centre National de la Recherche Scientifique - CNRS (FRANCE), Ecole Nationale Supérieure d'Ingénieurs de Caen - ENSICAEN (FRANCE), Institut National Polytechnique de Toulouse - INPT (FRANCE), National Aeronautics and Space Administration - NASA (USA), Ohio State University (USA), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Université de Caen Basse-Normandie (FRANCE), Université de Montpellier 2 (FRANCE), California Institute of Technology - Caltech (USA), and Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)

Subjects
Materials science, Solid-state physics, Matériaux, Analytical chemistry, chemistry.chemical_element, Spark plasma sintering, 02 engineering and technology, Crystal structure, 01 natural sciences, [SPI.MAT]Engineering Sciences [physics]/Materials, Optics, Seebeck coefficient, Yb4Sb3, 0103 physical sciences, Thermoelectric effect, Materials Chemistry, Anti-Th3P4, Electrical and Electronic Engineering, 010306 general physics, Thermoelectrics, business.industry, anti-Th3P4, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Thermoelectric materials, 3. Good health, Electronic, Optical and Magnetic Materials, Cerium, chemistry, Crystallite, 0210 nano-technology, business, thermoelectrics, spark plasma sintering
Abstract

International audience; Polycrystalline L4Sb3 (L = La, Ce, Sm, and Yb) and Yb4-x Sm (x) Sb-3, which crystallizes in the anti-Th3P4 structure type (I-43d no. 220), were synthesized via high-temperature reaction. Structural and chemical characterization were performed by x-ray diffraction and electronic microscopy with energy-dispersive x-ray analysis. Pucks were densified by spark plasma sintering. Transport property measurements showed that these compounds are n-type with low Seebeck coefficients, except for Yb4Sb3, which shows semimetallic behavior with hole conduction above 523 K. By partially substituting Yb by a trivalent rare earth we successfully improved the thermoelectric figure of merit of Yb4Sb3 up to 0.7 at 1273 K.

Published
2010
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19. High-temperature transport properties of complex antimonides with anti-Th3P4structure

Author

Jean-Claude Tedenac, Audrey Chamoire, Claude Estournès, Thierry Caillat, Franck Gascoin, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Centre interuniversitaire de recherche et d'ingenierie des matériaux (CIRIMAT), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC), Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - INPT (FRANCE), National Aeronautics and Space Administration - NASA (USA), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Université de Montpellier 2 (FRANCE), California Institute of Technology - Caltech (USA), and Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)

Subjects
Diffraction, VALENCE FLUCTUATION, EFFICIENCY, Materials science, Matériaux, Rare earth, Analytical chemistry, Mineralogy, Spark plasma sintering, 02 engineering and technology, 01 natural sciences, Antimonides, law.invention, Inorganic Chemistry, Metal, PHASES, YB4SB3, law, Seebeck coefficient, 0103 physical sciences, YB4BI3, THERMOELECTRIC PROPERTIES, 010302 applied physics, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Thermal conduction, YB4AS3, visual_art, visual_art.visual_art_medium, Crystallite, YB14MN1-XALXSB11, Electron microscope, High-temperature transport, 0210 nano-technology, SYSTEM
Abstract

International audience; Polycrystalline samples of R4Sb3 (R = La, Ce, Smand Yb) and Yb4-xR'Sb-x(3)(R' = Sm and La) have been quantitatively synthesized by high-temperature reaction. They crystallize in the anti-Th3P4 structure type (I (4) over bar 3d, no. 220). Structural and chemical characterizations have been performed by X-ray diffraction and electron microscopy with energy dispersive X-ray analysis. Powders have been densified by spark plasma sintering (SPS) at 1300 degrees C under 50 MPa of pressure. Transport property measurements show that these compounds are n-type with low Seebeck coefficient except for Yb4Sb3 that shows a typical metallic behavior with hole conduction. By partially substituting Yb by a trivalent rare earth we successfully improved the thermoelectric figure of merit of Yb4-xR'Sb-x(3) up to 0.75 at 1000 degrees C.

Published
2010
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20. Seismometer Detection of Dust Devil Vortices by Ground Tilt

Author

Naomi Murdoch, Philippe Lognonné, David Mimoun, Taichi Kawamura, Sharon Kedar, W. Bruce Banerdt, Ralph D. Lorenz, Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Département Electronique, Optronique et Signal (DEOS), Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Institut de Physique du Globe de Paris (IPGP), Université Pierre et Marie Curie - Paris 6 (UPMC)-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), 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), National Aeronautics and Space Administration (NASA) Mars Fundamental Research and Mars Data Analysis programs NNX12AJ47GNNX12AI04GView funding text, National Aeronautics and Space Administration (NASA) Mars Fundamental Research and Mars Data Analysis programs NNX12AJ47G NNX12AI04G View funding text, Institut de Physique du Globe de Paris - IPGP (FRANCE), Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), Université de Paris Diderot - Paris 7 (FRANCE), California Institute of Technology - Caltech (USA), and Johns Hopkins University - JHU (USA)

Subjects
Seismometer, Convection, Physics - Instrumentation and Detectors, 010504 meteorology & atmospheric sciences, Mars, FOS: Physical sciences, PRESSURE, FREQUENCY, 01 natural sciences, Physics::Geophysics, NOISE, Physics - Geophysics, Autre, Convective vortices, Geochemistry and Petrology, 0103 physical sciences, EARTH, Seismic refraction, 010303 astronomy & astrophysics, Dust devil, Instrumentation and Methods for Astrophysics (astro-ph.IM), RECORDS, Dust devils, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Mars Exploration Program, Geophysics, Instrumentation and Detectors (physics.ins-det), Vortex, Geophysics (physics.geo-ph), Physics - Atmospheric and Oceanic Physics, Tilt (optics), Amplitude, 13. Climate action, [SDU]Sciences of the Universe [physics], Atmospheric and Oceanic Physics (physics.ao-ph), Seismic pressure, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Geology, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report seismic signals on a desert playa caused by convective vortices and dust devils. The long-period (10-100s) signatures, with tilts of ~10$^{-7}$ radians, are correlated with the presence of vortices, detected with nearby sensors as sharp temporary pressure drops (0.2-1 mbar) and solar obscuration by dust. We show that the shape and amplitude of the signals, manifesting primarily as horizontal accelerations, can be modeled approximately with a simple quasi-static point-load model of the negative pressure field associated with the vortices acting on the ground as an elastic half space. We suggest the load imposed by a dust devil of diameter D and core pressure {\Delta}Po is ~({\pi}/2){\Delta}PoD$^2$, or for a typical terrestrial devil of 5 m diameter and 2 mbar, about the weight of a small car. The tilt depends on the inverse square of distance, and on the elastic properties of the ground, and the large signals we observe are in part due to the relatively soft playa sediment and the shallow installation of the instrument. Ground tilt may be a particularly sensitive means of detecting dust devils. The simple point-load model fails for large dust devils at short ranges, but more elaborate models incorporating the work of Sorrells (1971) may explain some of the more complex features in such cases, taking the vortex winds and ground velocity into account. We discuss some implications for the InSight mission to Mars., Comment: Contributed Article for Bulletin of the Seismological Society of America, Accepted 29th August 2015

Published
2015
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21. A novel facility for reduced-gravity testing: A setup for studying low-velocity collisions into granular surfaces

Author

Sara Morales Serrano, Claudia Valeria Nardi, Yves Gourinat, Iris Avila Martinez, Naomi Murdoch, David Mimoun, Tristan Janin, Cecily Sunday, Olivier Cherrier, Département Electronique, Optronique et Signal (DEOS), Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Institut Clément Ader (ICA), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-IMT École nationale supérieure des Mines d'Albi-Carmaux (IMT Mines Albi), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Centre National de la Recherche Scientifique - CNRS (FRANCE), Ecole nationale supérieure des Mines d'Albi-Carmaux - IMT Mines Albi (FRANCE), Institut National des Sciences Appliquées de Toulouse - INSA (FRANCE), Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), National Aeronautics and Space Administration - NASA (USA), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), California Institute of Technology - Caltech (USA), Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-IMT École nationale supérieure des Mines d'Albi-Carmaux (IMT Mines Albi), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), and California Institute of Technology (CALTECH)-NASA

Subjects
[SPI.OTHER]Engineering Sciences [physics]/Other, Surface (mathematics), Gravity (chemistry), 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Atwood machine, Experiment gravity, Accelerometer, 01 natural sciences, Acceleration, Autre, 0103 physical sciences, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Instrumentation, Regolith landing collision, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Projectile, Asteroid, Mechanics, Collision, Comet, Container (abstract data type), Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

This work presents an experimental design for studying low-velocity collisions into granular surfaces in low-gravity. In the experiment apparatus, reduced-gravity is simulated by releasing a free-falling projectile into a surface container with a downward acceleration less than that of Earth's gravity. The acceleration of the surface is controlled through the use of an Atwood machine, or a system of pulleys and counterweights. The starting height of the surface container and the initial separation distance between the projectile and surface are variable and chosen to accommodate collision velocities up to 20 cm/s and effective accelerations of ~0.1 - 1.0 m/s^2. Accelerometers, placed on the surface container and inside the projectile, provide acceleration data, while high-speed cameras capture the collision and act as secondary data sources. The experiment is built into an existing 5.5 m drop-tower frame and requires the custom design of all components, including the projectile, surface sample container, release mechanism and deceleration system. Data from calibration tests verify the efficiency of the experiment's deceleration system and provide a quantitative understanding of the performance of the Atwood system., 11 pages, 11 figures

Published
2016
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22. Future Mars geophysical observatories for understanding its internal structure, rotation, and evolution

Author

Martin Knapmeyer, Tilman Spohn, Véronique Dehant, Oliver Romberg, Sami W. Asmar, Doris Breuer, Benoit Langlais, Matthias Grott, Peter L. Read, Paolo Tortora, Attilio Rivoldini, Ralf Jaumann, Susanne Vennerstrøm, Jens Biele, François Forget, Catherine L. Johnson, Philippe Lognonné, Gerald Schubert, Sue Smrekar, Antoine Mocquet, Mathieu Le Feuvre, David Mimoun, Bruce Banerdt, Stephan Ulamec, Observatoire Royal de Belgique (ORB), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), German Aerospace Center (DLR), DLR Institut für Planetenforschung, Institut Pierre-Simon-Laplace (IPSL), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Department of Earth, Ocean and Atmospheric Sciences [Vancouver] (UBC EOAS), University of British Columbia (UBC), Université de Nantes (UN), 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), Département Electronique, Optronique et Signal (DEOS), Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Department of Atmospheric, Oceanic and Planetary Physics [Oxford] (AOPP), University of Oxford, Department of Earth and Space Sciences [Los Angeles], University of California [Los Angeles] (UCLA), University of California (UC)-University of California (UC), V. Dehant, B. Banerdt, P. Lognonné, M. Grott, S. Asmar, J. Biele, D. Breuer, F. Forget, R. Jaumann, C. Johnson, M. Knapmeyer, B. Langlai, M. Le Feuvre, D. Mimoun, A. Mocquet, P. Read, A. Rivoldini, O. Romberg, G. Schubert, S. Smrekar, T. Spohn, P. Tortora, S. Ulamec, S. Vennerstrøm, Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut de Physique du Globe de Paris - IPGP (FRANCE), Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), National Aeronautics and Space Administration - NASA (USA), Université de Paris Diderot - Paris 7 (FRANCE), Università di Bologna (ITALY), Université Pierre et Marie Curie, Paris 6 - UPMC (FRANCE), Université de La Réunion (FRANCE), California Institute of Technology - Caltech (USA), Deutsches Zentrum für Luft- und Raumfahrt - DLR (GERMANY), Ecole Normale Supérieure de Paris - ENS Paris (FRANCE), Ecole Polytechnique (FRANCE), Georges Lemaître Centre for Earth and Climate Research - TECLIM (BELGIUM), Institut national des sciences de l'Univers - INSU (FRANCE), National Space Institute (DENMARK), Royal Observatory of Belgium (BELGIUM), Planetary Science Institute (USA), Technical University of Denmark (DENMARK), Université Nantes Angers Le Mans - UNAM (FRANCE), University of California-Los Angeles - UCLA (USA), Université Catholique de Louvain - UCL (BELGIUM), University of British Columbia (CANADA), University of Oxford (UNITED KINGDOM), Jet Propulsion Laboratory - JPL (Pasadena, USA), Laboratoire de Planétologie et Géodynamique (Nantes, France), and Georges Lemaître Centre for Earth and Climate Research - TECLIM (Louvain-la-Neuve, Belgium)

Subjects
Seismometer, 010504 meteorology & atmospheric sciences, Rotation, Habitability, Mars, Interior structure, 01 natural sciences, Astrobiology, Autre, Interior Structure, Magnetic Field, 0103 physical sciences, MARS GEOPHYSICS, PLANETARY EXPLORATION, 010303 astronomy & astrophysics, Geothermal gradient, Seismology, 0105 earth and related environmental sciences, Radio Science, Physics, MARS ROTATION, Atmosphere, Geodetic datum, Biosphere, Astronomy and Astrophysics, Heat Flow, Mars Exploration Program, Geophysics, Planetary science, Magnetic field, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Terrestrial planet, Heat flow
Abstract

Our fundamental understanding of the interior of the Earth comes from seismology, geodesy, geochemistry, geomagnetism, geothermal studies, and petrology. For the Earth, measurements in those disciplines of geophysics have revealed the basic internal layering of the Earth, its dynamical regime, its thermal structure, its gross compositional stratification, as well as significant lateral variations in these quantities. Planetary interiors not only record evidence of conditions of planetary accretion and differentiation, they exert significant control on surface environments. We present recent advances in possible in-situ investigations of the interior of Mars, experiments and strategies that can provide unique and critical information about the fundamental processes of terrestrial planet formation and evolution. Such investigations applied on Mars have been ranked as a high priority in virtually every set of European, US and international high-level planetary science recommendations for the past 30 years. New seismological methods and approaches based on the cross-correlation of seismic noise by two seismic stations/landers on the surface of Mars and on joint seismic/orbiter detection of meteorite impacts, as well as the improvement of the performance of Very Broad-Band (VBB) seismometers have made it possible to secure a rich scientific return with only two simultaneously recording stations. In parallel, use of interferometric methods based on two Earth–Mars radio links simultaneously from landers tracked from Earth has increased the precision of radio science experiments by one order of magnitude. Magnetometer and heat flow measurements will complement seismic and geodetic data in order to obtain the best information on the interior of Mars. In addition to studying the present structure and dynamics of Mars, these measurements will provide important constraints for the astrobiology of Mars by helping to understand why Mars failed to sustain a magnetic field, by helping to understand the planet’s climate evolution, and by providing a limit for the energy available to the chemoautotrophic biosphere through a measurement of the surface heat flow. The landers of the mission will also provide meteorological stations to monitor the climate and obtain new measurements in the atmospheric boundary layer.

Published
2012
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23. Attention, sentiments and emotions towards emerging climate technologies on Twitter.

Author

Müller-Hansen F, Repke T, Baum CM, Brutschin E, Callaghan MW, Debnath R, Lamb WF, Low S, Lück S, Roberts C, Sovacool BK, and Minx JC

Abstract

Public perception of emerging climate technologies, such as greenhouse gas removal (GGR) and solar radiation management (SRM), will strongly influence their future development and deployment. Studying perceptions of these technologies with traditional survey methods is challenging, because they are largely unknown to the public. Social media data provides a complementary line of evidence by allowing for retrospective analysis of how individuals share their unsolicited opinions. Our large-scale, comparative study of 1.5 million tweets covers 16 GGR and SRM technologies and uses state-of-the-art deep learning models to show how attention, and expressions of sentiment and emotion developed between 2006 and 2021. We find that in recent years, attention has shifted from general geoengineering themes to specific GGR methods. On the other hand, there is little attention to specific SRM technologies and they often coincide with conspiracy narratives. Sentiments and emotions in GGR tweets tend to be more positive, particularly for methods perceived to be natural, but are more negative when framed in the geoengineering context., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

Published
2023
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