InSight Surface Operations, 26 Nov 2018- 21 Dec 2022 |
InSight Surface Operations, 26 Nov 2018- 21 Dec 2022 |
Nov 26 2018, 08:20 PM
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Merciless Robot Group: Admin Posts: 8785 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Congratulations to the InSight team on a successful landing! We'll discuss the remainder of the mission here.
-------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Mar 11 2020, 04:32 PM
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Member Group: Members Posts: 104 Joined: 3-February 20 From: Paris (France) Member No.: 8747 |
Hello,
In addition to post 867, I am offering you a translation of the article published on the CNES website (Centre Nationnal d'Etudes Spatiales) relating to the year of operation of the Insight seismometer on March. INSIGHT/SEIS: THE VEIL RISES ON THE INTERNAL STRUCTURE OF MARS More than 100 researchers analyzed the first dataset of the Insight mission’s SEIS seismeter. Thanks to 3 earthquakes, among the 171 events detected between January and September 2019, they establish that the upper crust of Mars is between 8 and 11 km thick and that its numerous fractures are covered with films of liquid water. These results are published in Nature Geosciences on February 24, 2020. Original link : https://insight.cnes.fr/fr/insightseis-le-v...interne-de-mars 3 SEISMIC NOISE PERIODS : On 18 December 2018, the Insight lander arm deposited the SEIS seismeter coordinated by the CNES on Mars. Analysis of the 1st dataset of its VBB sensors reveals the existence of 3 typical periods of seismic noise related to atmospheric activity thanks to the recordings of the meteorological station attached to the lander. From sunrise to sunset : the air heated by the Sun beats the ground. SEIS records many noises related to atmospheric turbulence. From sunset to midnight : Mars is extremely quiet with seismic noise about 500 times lower than seismic noise on Earth. This noise is the lowest ever measured by a seismic station! From midnight to sunrise: a light breeze from the southwest touches the surface and generates seismic noise by deforming the ground under air pressure. The extreme sensitivity of SEIS makes it possible to detect the smallest vibrations of the ground such as those related to the passage of dust devils (NDLR: dust tornadoes). We expected it, this first data set confirms it: SEIS will teach us a lot of new things about the Martian atmosphere» says Philippe Lognonné, professor at the University of Paris, geophysicist of the IPGP, Scientific Director of SEIS and 1st author of the article published in Nature Geosciences. TOP CRUST THICKNESS : ABOUT 10 KM From January to September 2019, the researchers identified 171 seismic events, 20 of which would correspond to earthquakes of magnitude 3 to 4. Three earthquakes were particularly well detected by the French SEIS sensors: the earthquake of 7 April 2019 (Sol 128 because the 128th Martian day of the Insight mission) estimated at a magnitude of about 2.1 the earthquake of 23 May 2019 (Sol 173) estimated at a magnitude of approximately 3.6 the earthquake of 26 July 2019 (Sol 235) estimated at a magnitude of approximately 3.6. Thanks to the different arrival times of the P and S waves, the researchers determined the existence of a higher crust of thickness between 8 and 11 km. This top crust of about 10 km is more friable and less consolidated than the bottom crust on which it rests. It has been altered by surface processes and probably also by meteoritic impacts. Below, is a crust with more original and less fractured rocks, with a speed 50% faster, a jump from 2 km/s to 3 km/s. This first series of recordings did not allow us to locate the zone of discontinuity between the crust and the mantle (NDLR: the thickness of the crust as a whole). This would require a stronger earthquake or SEIS recording of surface waves, Philippe Lognonné explains. https://insight.cnes.fr/sites/default/files...g?itok=ohCS4maP A FRACTURED UPPER CRUST Another conclusion of the fine analysis of the recordings of these 3 earthquakes: the upper crust of Mars is very fractured and its faults are covered with films of liquid water. «The velocity of wave propagation in the upper crust of Mars is in values intermediate to the one on the Moon and Earth. This assumes a relatively fractured upper crust. In terms of attenuation of seismic waves, we find a value 3 times greater than on the Moon, comparable to those of crystalline massifs such as the Armoricain massif in France (Bretagne) which suggests the presence of moisture. But don’t imagine large amounts of water, it only takes a few films of liquid water molecules to explain the attenuation of the seismic waves we observe,” insists Philippe Lognonné. On the CNES side, we are very proud to have succeeded in this instrument which has been complex to develop. A real watch jewel! Its implementation was based on close cooperation between the IPGP, Sodern, foreign partners and the CNES. Today, SEIS delivers its first seismic measurements and this is only the beginning. We are only beginning to lift the veil on Martian seismicity!» concludes Francis Rocard, Head of Solar System Exploration Programs at the CNES. THE CNES, MASTER OF CLOCKS In order to link SEIS records to earthquakes or atmospheric phenomena, it is essential to have a good dating of these events. It is the SISMOC, a centre dedicated to the Insight mission at the CNES in Toulouse, that provides scientists with the consistent dating of seismic and meteorological data from the instrument clocks. Now, these clocks — which are more counters than real clocks giving hours have a drift in different time of up to a few seconds a day! This work was anticipated for SEIS and the APSS weather station because it was known that changes in atmospheric pressure would have an impact on seismic measurements. Every second, SEIS sends a clock to APSS. It is retransmitted to SISMOC several times a day with the APSS clock data, which allows us to compare their counter and recalculate the whole with an accuracy of a few ms» explains Ludovic Rochas, SEIS Operations System Engineer at CNES. HP3 In the article published in Nature Geosciences, the researchers also present the analysis of seismic recordings during attempts to penetrate the ground by the Insight HP3 probe. To provide consistent dating, MOCIS had to find a trick. During the penetration attempts of HP3, we program SEIS to transmit its dating much more frequently to the lander, every minute. These datations are then correlated with those that HP3 sends to the lander». The researchers were able to calculate that the shocks caused by HP3 averaged 9.4 ms to travel a distance of 1.1 m, confirming that the surface soil on which Insight landed is composed of very brittle materials, unlikely to spread rapidly propagating surface waves. |
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