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Institut supérieur de l'aéronautique et de l'espace
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About: Institut supérieur de l'aéronautique et de l'espace is a based out in . It is known for research contribution in the topics: Mars Exploration Program & Seismometer. The organization has 445 authors who have published 644 publications receiving 8049 citations. The organization is also known as: ISAE SUPAERO & National Higher French Institute of Aeronautics and Space.
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TL;DR: It is reported that thermal fatigue, a mechanism of rock weathering and fragmentation with no subsequent ejection, is the dominant process governing regolith generation on small asteroids and that thermal fragmentation induced by the diurnal temperature variations breaks up rocks larger than a few centimetres more quickly than do micrometeoroid impacts.
Abstract: Space missions1, 2 and thermal infrared observations3 have shown that small asteroids (kilometre-sized or smaller) are covered by a layer of centimetre-sized or smaller particles, which constitute the regolith. Regolith generation has traditionally been attributed to the fall back of impact ejecta and by the break-up of boulders by micrometeoroid impact4, 5. Laboratory experiments6 and impact models4, however, show that crater ejecta velocities are typically greater than several tens of centimetres per second, which corresponds to the gravitational escape velocity of kilometre-sized asteroids. Therefore, impact debris cannot be the main source of regolith on small asteroids4. Here we report that thermal fatigue7, 8, 9, a mechanism of rock weathering and fragmentation with no subsequent ejection, is the dominant process governing regolith generation on small asteroids. We find that thermal fragmentation induced by the diurnal temperature variations breaks up rocks larger than a few centimetres more quickly than do micrometeoroid impacts. Because thermal fragmentation is independent of asteroid size, this process can also contribute to regolith production on larger asteroids. Production of fresh regolith originating in thermal fatigue fragmentation may be an important process for the rejuvenation of the surfaces of near-Earth asteroids, and may explain the observed lack of low-perihelion, carbonaceous, near-Earth asteroids10.
318 citations
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California Institute of Technology1, Cornell University2, ETH Zurich3, University of British Columbia4, Planetary Science Institute5, Institut Universitaire de France6, Institut de Physique du Globe de Paris7, University of Paris8, German Aerospace Center9, University of California, Los Angeles10, Universities Space Research Association11, University of Oxford12, Colorado School of Mines13, Max Planck Society14, Imperial College London15, Université catholique de Louvain16, Royal Observatory of Belgium17, University of California, Berkeley18, Institut supérieur de l'aéronautique et de l'espace19, Goddard Space Flight Center20, Smithsonian Institution21, Princeton University22, Austrian Academy of Sciences23, Virginia Tech24, University of Cologne25, Space Science Institute26, Johns Hopkins University Applied Physics Laboratory27, Paul Sabatier University28, Stony Brook University29, École normale supérieure de Lyon30, University of Nantes31, Texas Tech University32, University of California, Santa Cruz33, Spanish National Research Council34, University of Maryland, College Park35, Southern Methodist University36, Johns Hopkins University37, University of Bristol38, State University of New York at Geneseo39, Marshall Space Flight Center40
TL;DR: For example, the first ten months of the InSight lander on Mars revealed a planet that is seismically active and provided information about the interior, surface and atmospheric workings of Mars as mentioned in this paper.
Abstract: NASA’s InSight (Interior exploration using Seismic Investigations, Geodesy and Heat Transport) mission landed in Elysium Planitia on Mars on 26 November 2018. It aims to determine the interior structure, composition and thermal state of Mars, as well as constrain present-day seismicity and impact cratering rates. Such information is key to understanding the differentiation and subsequent thermal evolution of Mars, and thus the forces that shape the planet’s surface geology and volatile processes. Here we report an overview of the first ten months of geophysical observations by InSight. As of 30 September 2019, 174 seismic events have been recorded by the lander’s seismometer, including over 20 events of moment magnitude Mw = 3–4. The detections thus far are consistent with tectonic origins, with no impact-induced seismicity yet observed, and indicate a seismically active planet. An assessment of these detections suggests that the frequency of global seismic events below approximately Mw = 3 is similar to that of terrestrial intraplate seismic activity, but there are fewer larger quakes; no quakes exceeding Mw = 4 have been observed. The lander’s other instruments—two cameras, atmospheric pressure, temperature and wind sensors, a magnetometer and a radiometer—have yielded much more than the intended supporting data for seismometer noise characterization: magnetic field measurements indicate a local magnetic field that is ten-times stronger than orbital estimates and meteorological measurements reveal a more dynamic atmosphere than expected, hosting baroclinic and gravity waves and convective vortices. With the mission due to last for an entire Martian year or longer, these results will be built on by further measurements by the InSight lander. Geophysical and meteorological measurements by NASA’s InSight lander on Mars reveal a planet that is seismically active and provide information about the interior, surface and atmospheric workings of Mars.
299 citations
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TL;DR: The data support the suitability of fNIRS to assess the mental effort related to human operations and represents a promising tool for the measurement of neural efficiency in other contexts such as training programs or the clinical setting.
Abstract: An improved understanding of how the brain allocates mental resources as a function of task difficulty is critical for enhancing human performance. Functional near infrared spectroscopy (fNIRS) is a field-deployable optical brain monitoring technology that provides a direct measure of cerebral blood flow in response to cognitive activity. We found that fNIRS was sensitive to variations in task difficulty in both real-life (flight simulator) and laboratory settings (tests measuring executive functions), showing increased concentration of oxygenated hemoglobin (HbO2) and decreased concentration of deoxygenated hemoglobin (HHb) in the prefrontal cortex as the tasks became more complex. Intensity of prefrontal activation (HbO2 concentration) was not clearly correlated to task performance. Rather, activation intensity shed insight on the level of mental effort, i.e., how hard an individual was working to accomplish a task. When combined with performance, fNIRS provided an estimate of the participants’ neural efficiency, and this efficiency was consistent across levels of difficulty of the same task. Overall, our data support the suitability of fNIRS to assess the mental effort related to human operations and represents a promising tool for the measurement of neural efficiency in other contexts such as training programs or the clinical setting.
276 citations
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TL;DR: Results show that both fNIRS and HRV are sensitive to different levels of mental workload; notably, lower prefrontal activation as well as a lower LF/HF ratio at the highest level of difficulty, suggest that these measures are suitable for mental overload detection.
226 citations
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Institut de Physique du Globe de Paris1, Institut Universitaire de France2, California Institute of Technology3, Imperial College London4, ETH Zurich5, Max Planck Society6, Institut supérieur de l'aéronautique et de l'espace7, University of Cologne8, University of Toulouse9, University of California, Santa Cruz10, Claude Bernard University Lyon 111, University of Paris12, University of Nantes13, University of California, Los Angeles14, University of Zurich15, Free University of Berlin16, University of Maryland, College Park17, Centre national de la recherche scientifique18, University of Stuttgart19, Colorado School of Mines20, École des ponts ParisTech21, German Aerospace Center22, University of Bristol23, Princeton University24, Johns Hopkins University Applied Physics Laboratory25, École normale supérieure de Lyon26, University of Oxford27, Centre National D'Etudes Spatiales28, International Space Science Institute29, Kaiserslautern University of Technology30, Marshall Space Flight Center31, Cornell University32, Planetary Science Institute33, University of British Columbia34, Instituto Nacional de Técnica Aeroespacial35
TL;DR: In this paper, the authors measured the crustal diffusivity and intrinsic attenuation using multiscattering analysis and found that seismic attenuation is about three times larger than on the Moon, which suggests that the crust contains small amounts of volatiles.
Abstract: Mars’s seismic activity and noise have been monitored since January 2019 by the seismometer of the InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) lander. At night, Mars is extremely quiet; seismic noise is about 500 times lower than Earth’s microseismic noise at periods between 4 s and 30 s. The recorded seismic noise increases during the day due to ground deformations induced by convective atmospheric vortices and ground-transferred wind-generated lander noise. Here we constrain properties of the crust beneath InSight, using signals from atmospheric vortices and from the hammering of InSight’s Heat Flow and Physical Properties (HP3) instrument, as well as the three largest Marsquakes detected as of September 2019. From receiver function analysis, we infer that the uppermost 8–11 km of the crust is highly altered and/or fractured. We measure the crustal diffusivity and intrinsic attenuation using multiscattering analysis and find that seismic attenuation is about three times larger than on the Moon, which suggests that the crust contains small amounts of volatiles. The crust beneath the InSight lander on Mars is altered or fractured to 8–11 km depth and may bear volatiles, according to an analysis of seismic noise and wave scattering recorded by InSight’s seismometer.
221 citations
Authors
Showing all 450 results
Name | H-index | Papers | Citations |
---|---|---|---|
Xuan Wang | 53 | 317 | 15482 |
Olivier Besson | 34 | 196 | 3583 |
Raphaël F. Garcia | 33 | 127 | 3438 |
Jean-Baptiste Ruffio | 31 | 101 | 3644 |
Frédéric Dehais | 29 | 135 | 2377 |
Naomi Murdoch | 28 | 119 | 2611 |
Daniel E. Callan | 28 | 59 | 3176 |
Patrick Pons | 27 | 312 | 3010 |
Christophe Bouvet | 27 | 132 | 2849 |
David Mimoun | 25 | 96 | 1924 |
Pierre Magnan | 25 | 165 | 2186 |
Olga Battaïa | 25 | 110 | 2209 |
Laurent Cordier | 24 | 92 | 2421 |
Mickaël Causse | 24 | 95 | 1735 |
Germain Rousseaux | 22 | 95 | 1632 |