High Precision SEIS Calibration for the InSight Mission and Its Applications

Abstract Part of the InSight mission, the SEIS instrument (Seismic Experiment for Interior Structures), is planned to arrive on Mars in November 2018. In order to prepare its future recordings on the red planet, special attention was directed towards calibrating the seismometer in-situ on the Martian surface. Besides relative calibrations, we studied the possibility of actively calibrating the two kinds of seismometers onboard SEIS, the Very Broad Band seismometers (VBB) and the Short Period seismometers (SP) and extended the analysis towards a possible absolute calibration. For that purpose, we developed additional noise models at low frequency and elaborate on how they will be sensed by the seismic sensors from long-period data recorded by the seismometer. Such work will improve SEIS capabilities to unveil the inner structure of Mars by checking SEIS well-being and with applications such as gravimetry with the main Phobos tide. The current calibration procedure is planned to take one hour to calibrate the VBB sensors using the SP sensors, and determine the VBB gain with an accuracy of 0.4%, good enough to resolve the state of the Martian core

SEIS: Insight's Seismic Experiment for Internal Structure of Mars.

By the end of 2018, 42 years after the landing of the two Viking seismometers on Mars, InSight will deploy onto Mars' surface the SEIS (Seismic Experiment for Internal Structure) instrument; a six-axes seismometer equipped with both a long-period three-axes Very Broad Band (VBB) instrument and a three-axes short-period (SP) instrument. These six sensors will cover a broad range of the seismic bandwidth, from 0.01 Hz to 50 Hz, with possible extension to longer periods. Data will be transmitted in the form of three continuous VBB components at 2 sample per second (sps), an estimation of the short period energy content from the SP at 1 sps and a continuous compound VBB/SP vertical axis at 10 sps. The continuous streams will be augmented by requested event data with sample rates from 20 to 100 sps. SEIS will improve upon the existing resolution of Viking's Mars seismic monitoring by a factor of ∼ 2500 at 1 Hz and ∼ 200 000 at 0.1 Hz. An additional major improvement is that, contrary to Viking, the seismometers will be deployed via a robotic arm directly onto Mars' surface and will be protected against temperature and wind by highly efficient thermal and wind shielding. Based on existing knowledge of Mars, it is reasonable to infer a moment magnitude detection threshold of M w ∼ 3 at 40 ∘ epicentral distance and a potential to detect several tens of quakes and about five impacts per year. In this paper, we first describe the science goals of the experiment and the rationale used to define its requirements. We then provide a detailed description of the hardware, from the sensors to the deployment system and associated performance, including transfer functions of the seismic sensors and temperature sensors. We conclude by describing the experiment ground segment, including data processing services, outreach and education networks and provide a description of the format to be used for future data distribution.Electronic supplementary materialThe online version of this article (10.1007/s11214-018-0574-6) contains supplementary material, which is available to authorized users

The seismicity of Mars

The InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission landed in Elysium Planitia on Mars on 26 November 2018 and fully deployed its seismometer by the end of February 2019. The mission aims to detect, characterize and locate seismic activity on Mars, and to further constrain the internal structure, composition and dynamics of the planet. Here, we present seismometer data recorded until 30 September 2019, which reveal that Mars is seismically active. We identify 174 marsquakes, comprising two distinct populations: 150 small-magnitude, high-frequency events with waves propagating at crustal depths and 24 low-frequency, subcrustal events of magnitude Mw 3–4 with waves propagating at various depths in the mantle. These marsquakes have spectral characteristics similar to the seismicity observed on the Earth and Moon. We determine that two of the largest detected marsquakes were located near the Cerberus Fossae fracture system. From the recorded seismicity, we constrain attenuation in the crust and mantle, and find indications of a potential low-S-wave-velocity layer in the upper mantle. © 2020, The Author(s), under exclusive licence to Springer Nature Limited.We acknowledge NASA, CNES and its partner agencies and institutions (UKSA, SSO, DLR, JPL, IPGP-CNRS, ETHZ, IC and MPS-MPG) and the flight operations team at JPL, SISMOC, MSDS, IRIS-DMC and PDS for providing SEIS data. The Swiss co-authors were jointly funded by (1) the Swiss National Science Foundation and French Agence Nationale de la Recherche (SNF-ANR project 157133 ‘Seismology on Mars’), (2) the Swiss National Science Foundation (SNF project 172508 ‘Mapping the internal structure of Mars’), (3) the Swiss State Secretariat for Education, Research and Innovation (SEFRI project ‘MarsQuake Service-Preparatory Phase’) and (4) ETH Research grant no. ETH-06 17-02. Additional support came from the Swiss National Supercomputing Centre (CSCS) under project ID s922. The Swiss contribution in the implementation of the SEIS electronics was made possible by funding from the federal Swiss Space Office (SSO) and contractual and technical support from the ESA-PRODEX office. The French Team acknowledge the French Space Agency CNES, which has supported and funded all SEIS-related contracts and CNES employees, as well as CNRS and the French team universities for personal and infrastructure support. Additional support was provided by ANR (ANR-14-CE36-0012-02 and ANR-19-CE31-0008-08) and, for the IPGP team, by the UnivEarthS Labex programme (ANR-10-LABX-0023), IDEX Sorbonne Paris Cité (ANR-11-IDEX-0005-0). SEIS-SP development and delivery were funded by the UK Space Agency. A portion of the work was carried out at the InSight Project at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. The MPS SEIS team acknowledges funding for development of the SEIS leveling system by the DLR German Space Agency. We thank gempa GmbH for software development related to the MQS tools. This paper is InSight contribution number 102.Peer reviewe

SEIS: Insight’s Seismic Experiment for Internal Structure of Mars

By the end of 2018, 42 years after the landing of the two Viking seismometers on Mars, InSight will deploy onto Mars’ surface the SEIS (Seismic Experiment for Internal Structure) instrument; a six-axes seismometer equipped with both a long-period three-axes Very Broad Band (VBB) instrument and a three-axes short-period (SP) instrument. These six sensors will cover a broad range of the seismic bandwidth, from 0.01 Hz to 50 Hz, with possible extension to longer periods. Data will be transmitted in the form of three continuous VBB components at 2 sample per second (sps), an estimation of the short period energy content from the SP at 1 sps and a continuous compound VBB/SP vertical axis at 10 sps. The continuous streams will be augmented by requested event data with sample rates from 20 to 100 sps. SEIS will improve upon the existing resolution of Viking’s Mars seismic monitoring by a factor of ∼ 2500 at 1 Hz and ∼ 200 000 at 0.1 Hz. An additional major improvement is that, contrary to Viking, the seismometers will be deployed via a robotic arm directly onto Mars’ surface and will be protected against temperature and wind by highly efficient thermal and wind shielding. Based on existing knowledge of Mars, it is reasonable to infer a moment magnitude detection threshold of Mw ∼ 3 at 40◦ epicentral distance and a potential to detect several tens of quakes and about five impacts per year. In this paper, we first describe the science goals of the experiment and the rationale used to define its requirements. We then provide a detailed description of the hardware, from the sensors to the deployment system and associated performance, including transfer functions of the seismic sensors and temperature sensors. We conclude by describing the experiment ground segment, including data processing services, outreach and education networks and provide a description of the format to be used for future data distribution

Apport de l’imagerie dans le diagnostic d’un adenome hypophysaire a manifestations ophtalmologiques chez un adolescent

La tomodensitométrie continue de jouer un rôle prépondérant dans le diagnostic des affections intracrâniennes dans les pays en développement.Nous rapportons le cas d’un adolescent de 16 ans, élève, venu consulter au centre hospitalier régional de Sokodé pour céphalées chroniques et baisse progressive et bilatérale de la vision. Un adénome hypophysaire a été évoqué devant les manifestations cliniques majoritairement ophtalmologiques. Le diagnostic d’un syndrome de masse hypophysaire a été confirmé par imagerie tomodensitométrique. La revue de la littérature nous apprend qu’il existe néanmoins des discordances entre les résultatsanatomo-histopathologiques des pièces d’exérèses chirurgicales, et les résultats des imageries que ce soit en tomodensitométrie ou en IRM. L’introduction de l’IRM de haute résolution permet de réduire cettediscordance, mais il faut retenir que l’expérience et la compétence du manipulateur restent de mise.Mots clés : Adénome hypophysaire, diagnostique, tomodensitométrie, IRM.The continuous tomodensitométrie to play a major role in the diagnosis of the affections intracrâniennes in the countries in development.We return the case of a teenager of 16 years, pupil, come to consult to the regional hospitable center of Sokodé for chronic céphalées and progressive and bilateral decrease of the vision. An adenoma hypophysaire has been evoked before the demonstrations clinics majoritairement ophtalmologiques. The diagnosis of a syndrome of mass hypophysaire has been confirmed by imagery tomodensitométrique. The magazine of the literature learns us that some conflicts exist nevertheless between the results anatomo-histopathologiques of the pieces of surgical exérèses, and the results of the imagery that it is in tomodensitométrie or in IRM. The introduction of the high resolution IRM permits to reduce this conflict,but it is necessary to keep that the experience and the manipulator's expertise remain stake.Key words: Adenoma hypophysaire, diagnose, tomodensitométrie, IRM

Prévalence de la cécité et des affections oculaires dans la région centrale du Togo,

The blindness represents an economic weight, a social problem and of public health. To Togo, the size of the problem is currently known pain. The objective of the present survey is to appreciate the prevalence of the blindness and the one of the ocular affections in the Central Region. It is about a descriptive transverse survey in farming environment that has been driven in 31 villages selected according to the technique said of systematic pull (method of the steps) among 161 inclusive villages. The households have been chosen by the same technique. In every household, all people have been examined. The size of the sample was estimated to 5 535 according to the formula of Schwartz. On 5 758 investigated, the prevalence of the blindness was of 1% about and the cataract represented the first reason (58%). The other recovered affections oculars were dominated by the conjunctivitis (15.27%), pterygions (4.15%) and ametropies (3.66%). The cataract stays the first reason of blindness in the Central Region and close to 70% of the blinding affections recovered are either curable either avoidable. A project of struggle against the blindness to well coordinated communal basis would contribute to reduce drastic way the blindness in the Central Region.Keywords : Prévalence, blindness, cataract, ocular affections, Central Region, TogoJ. Rech. Sci. Univ. Lomé (Togo), 2012, Série D, 14(1) : 111-11

La phacoemulsification en Afrique Subsaharienne: resultats fonctionnels et contraintes locales

But: Rapporter les résultats fonctionnels de la phacoémulsification en milieu sub-saharien.Matériels et méthodes: Il s’agit d’une étude rétrospective descriptive sur dossiers de patients opérés par la phacoémulsification avec une implantation en chambre postérieure de Janvier 2011 à Décembre 2012. Les données épidémiologiques (âge, sexe), cliniques (examen ophtalmologique, calcul d’implant), thérapeutiques et évolutifs (complications peropératoires et postopératoires, acuité visuelle à 4 ou 6 semaines post opératoires et astigmatisme) ont été précisées.Résultats: Cent douze yeux (29,6%) de 100 personnes ont été étudiés. L’âge moyen était de 61 ans ± 11,3 ans avec un sex-ratio de 1,13. Quatre-vingt et quatre pourcents des patients percevaient la lumière et 94% des cataractes étaient totales. Les complications étaient représentées par 0,9% de capsulorhexis curviligne discontinu, 1,8% de rupture capsulaire et 16,1% (18 yeux) d’oedème cornéen. Les implants utilisés étaient souples chez 59,9% et 62,5% étaient emmétropisants. Cinq pourcents avait entre 1/10 et 2/10 d’acuité visuelle (AV), 95% avaient une AV ≥3/10, tous les yeux (80) corrigés avaient de bons résultats (AV ≥ 3/10) dont 89,6% une AV ≥5/10.Conclusion: La phacoémulsification a apporté de très bons résultats fonctionnels en dépit des contraintes locales liées au type de cataracte et à la disponibilité des consommables. Son intégration progressive aux techniques préexistantes améliorerait la qualité chirurgicale dans les pays en développement.Mots clés: Phacoémulsification ; cataracte, Afrique subsaharienne ; implant soupleEnglish Title: Phacoemulsification in sub-Saharan Africa: functional outcome and local constraintsEnglish AbstractAims: To report the functional results of phacoemulsification in sub-Saharan environment.Materials and Methods: This is a retrospective descriptive study of patient records made by phacoemulsification with posterior chamber implantation from January 2011 to December 2012 epidemiological data (age, sex), clinical (ophthalmologic examination. calculation of implant), therapeutic and evolutionary (intraoperative and postoperative complications, visual 4 or 6 weeks post-op and astigmatism) acuity were specified.Results: One hundred and twelve eyes (29.6%) of 100 persons were studied. The average age was 61 years ± 11.3 years with a sex ratio of 1.13. Eighty-four percent of patients saw the light and 94% of cataracts were total. Complications were represented by 0.9% discontinuous curvilinear capsulorhexis, 1.8% of capsular rupture and 16.1% (18 eyes) with corneal oedema. The implants used were flexible in 59.9% and 62.5% were of going toward normal VA. Five percent had between 1/10 and 2/10 visual acuity (VA), 95% had a VA ≥ 3/10, all eyes (80) corrected had good results (VA ≥ 3/10) 89, 6% VA ≥ 5/10.Conclusion: Phacoemulsification has made very good functional results despite local constraints to the type of cataract and availability of consumables. Its gradual integration with existing technologies improve surgical quality in developing countries.Keywords: Phacoemulsification; cataract; sub-saharan Africa; soft len

High Precision SEIS Calibration for the InSight Mission and Its Applications

International audiencePart of the InSight mission, the SEIS instrument (Seismic Experiment for Interior Structures), is planned to arrive on Mars in November 2018. In order to prepare its future recordings on the red planet, special attention was directed towards calibrating the seismometer in-situ on the Martian surface. Besides relative calibrations, we studied the possibility of actively calibrating the two kinds of seismometers onboard SEIS, the Very Broad Band seismometers (VBB) and the Short Period seismometers (SP) and extended the analysis towards a possible absolute calibration. For that purpose, we developed additional noise models at low frequency and elaborate on how they will be sensed by the seismic sensors from long-period data recorded by the seismometer. Such work will improve SEIS capabilities to unveil the inner structure of Mars by checking SEIS well-being and with applications such as gravimetry with the main Phobos tide. The current calibr

Atteintes oculaires en milieu professionnel a risque: cas des soudeurs de la Ville de Cotonou au Benin

Objectif: Evaluer les atteintes oculaires en milieu professionnel à risque comme chez le cas des soudeurs de la ville de Cotonou au Bénin.Méthode: C’est une étude transversale qui a permis de recueillir et d’analyser à l’aide d’une fiche d’enquête pré-codée les atteintes oculaires qui sont des risques que courent les soudeurs dans l’exercice de leur profession.Résultats: 157 soudeurs ont été enquêtés. Les adultes jeunes soit 69,5% de l’échantillon étaient les plus représentés et l’âge moyen était de 27 ans 67,5% des soudeurs enquêtés sont victimes d’atteintes oculaires lors de la soudure. La chaleur dans 95,5% des cas et les débris métalliques dans 82,5% étaient les agents en cause les plus incriminés dans les atteintes oculaires. La cornée dans 89,8% des cas et la conjonctive dans 76,4% des cas étaient les plus touchées lors des atteintes oculaires.Conclusion: les soudeurs sont exposés dans l’exercice de leur fonction aux risques d’atteinte oculaire qui ont une fréquence et une gravité considérable. L’utilisation des mesures préventives est indispensable pour réduire la fréquence de ces atteintes et la prévalence de la cécité liée aux atteintes en milieu de soudure.Mots clés: atteintes oculaires, risques professionnels, soudure, métalliqueEnglish Title: Eye injuries in riskful workplace: case of the welders of the city of Cotonou in BeninEnglish AbstractAim: To evaluate eye damage among workers in high risk conditions as in the case welders from the city of Cotonou in Benin.Methods: This was a cross-sectional study that resulted in the collection and analysis using a pre-coded survey form of eye damage that is a risk for welders in the practice of their profession.Results: 157 welders were surveyed. Young adults, 69.5% of the sample, were the most represented and the average age was 27 years. 67.5% of welders surveyed suffered from eye injuries during their working. Heat in 95.5% of cases and metal debris in 82.5% of cases were the most responsible agents involved in eye injuries. The cornea in 89.8% of the cases and the conjunctiva in 76.4% of the cases were the most affected in the eyes.Conclusion: Welders are exposed in the exercise of their function to the risks of ocular involvement which have a considerable frequency and severity. The use of preventive measures is essential to reduce the incidence of blindness and blindness prevalence.Keywords: eye damage, occupational hazards, welding, metalli