NASA
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Astronomers working with InSight automated station data published the first scientific results obtained over 10 months of operation. It was confirmed that Mars is still a seismically active planet, and its crust is heterogeneous in composition and contains a small amount of volatile substances. It was also possible to build a map of the structure of subsurface layers at the landing site of the device and learn more about the weather on the Red Planet. Articles (1,2,3,4,5) published in magazines Nature geoscience and Nature communications.
InSight Automated Research Station committed soft landing on Mars in November 2018 in the highlands Elysium, and in the middle of December 2018 and February 2019, two main scientific tools of the mission were brought to the surface: the HP drill3, designed to measure heat fluxes in Martian soil, and the SEIS seismograph. Early February 2019 beginning APSS sensor system, which collects weather data on a regular basis, is fully operational.
One of the main results of the first ten months of the station’s operation was the confirmation that Mars is still a seismically active planet. As of September 30, 2019, the seismograph recorded 174 seismic events, of which 150 were high-frequency, and 24 events were low-frequency, with magnitude Mw = 3-4, the nature of which indicates their tectonic nature. Among them, 13 cases can be distinguished, for which one can approximately calculate the location of the source and magnitude.
The frequency of seismic events with lower magnitudes is similar to the frequency of similar events inside the plates of the earth’s crust, no powerful marquakes were observed. SEIS data show that the upper layers of the crust of Mars to depths of 8–11 kilometers have undergone strong changes and are heterogeneous, in addition, the crust contains a small amount of volatile substances and strong scattering of seismic waves occurs in it.
–Comparison of seismic noise on Mars, the Moon and the Earth.
P. Lognonné et al. / Nature Geoscience (2020).
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-Matching Seismograph and HP Instrument Data3As well as studying the images taken by the station’s onboard cameras, it was possible to compose a picture of the structure of subsurface layers at the InSight landing site, which is located on the slope of an eroded impact crater called the Holmsted Basin, with a diameter of about 27 meters. His age is estimated at 400-500 million years. The surface around the station is relatively smooth, sandy, rich in small granules and pebbles, with a small amount of relatively large stones. About ten impact craters with a diameter of 1-10 meters can be seen in panoramic images within 20 meters of the landing platform.
The surface layer is a hard crust (dyurakrast), which consists of stones and pebbles cemented in a fine-grained matrix. The layer of fragmented heterogeneous regolith, which has a thickness of about 3–18 meters and covers the breccia, which then passes into the basalt layer, lies deeper.
–Construction of subsurface layers at the InSight landing site. Surface dust and stones (6), traces from engine exhausts of the station where dyurakrast (8), small pits (9), overlapping covered craters (4, 5, 10), stones (7), regolith (3), layers were noted breccias (2) and cracked basalt layers (1).
M. Golombek et al. / Nature Communications (2020).
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-Weather sensor data show that wind gain is observed from about midnight to early in the morning, as colder air descends from the highlands in the southern hemisphere to the lowland regions in the northern hemisphere where the station is located. During the day, heating the air with the sun’s rays causes convective currents. The wind intensifies again in the late afternoon, when atmospheric pressure drops and dust devils appear. By late evening, the wind subsides, and the situation around the landing platform becomes calm. From late evening until midnight, atmospheric conditions are so favorable that the seismograph becomes able to record tectonic noise from the depths of the planet. Night surveys showed that a glow was observed in the sky for a long time after twilight (with an intensity of about 10 relays) not due to light reflection from the satellites of Mars. It was previously predicted that it is caused by photochemical reactions in the upper atmosphere, however, they were able to observe it only now.
You can read about mission details and riddles of Martian geology in our materials. “Look inside the Red Planet” and Seismograph for Mars.
Alexander Voytyuk
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