Certainly, Toulouse is a real capital of Mars research. besides spectrometerspectrometer laser ChemCamChemCam And the SupercamWe also made the first thing Martian seismometerMartian seismometerWith amazing accuracy. and lo His retirement is imminent Nearing the end of the Insight mission, Seis continues to surprise us, and today he completes his final science objective. So it is a complete success for the tool, which has measured over 1300 earthquakesearthquakes Since early 2019.
The InSight lander recorded a meteor entering the weakened atmosphere of Mars, exploding and then impacting Earth. Listen to the recording taken on the surface of Mars. © NASA, JPL-Caltech
Huge power of authentication
” Now discovering more effects meteoritesmeteorites On Mars than on Earth Rafael Garcia tells us, the only impact recorded by seismographs on Earth occurred in Bolivia, creating a crater with a diameter of 10 metres. As a reminder, the Russian examples of TunguskaTunguska or Chelyabinsk They are explosions in the sky, not collisions.
The only time localization was done using seismometers was during an explosion GasGas In Germany. But, here, we are already on the surface of Mars. It uses one of the eight sensors in orbitingorbiting Around the planet we were able to complete the work of Seis: a seismometer locates impacts, CTX cameras and Hi Rise From Mars reconnaissance vehicle Confirm them, locate the pits by comparing before and after impact, and even communicate information about their size. The power of event documentation is unparalleled in space exploration, and extremely useful for the future.
Manned mission requests
Seis’ mission is over, and his legacy on the Moon has already been planned. Two seismic scales, forming Earthquake wing on the other side – FSS, scheduled to land at Schrödinger crater, on the far side, near the South Pole, in 2025. The FSS will be built under project management Jet Propulsion LaboratoryJet Propulsion Laboratoryin cooperation with Cnes and French aerospace laboratories involved in the supply sensorssensors (Institute of physicalphysical Paris Globe, ISAE-Supaero, and Laboratory of Cosmology and Astroparticles – APC). Using this new method, these seismographs will be able to document the flow of meteorites impacting the south pole of the moon, where NASANASA intends to send it astronautsastronauts for the Artemis program, and even the construction of a lunar base there. As a reminder, the first lunar seismometer was deposited by buzzing aldrinbuzzing aldrin when Apollo 11 mission.
Interview with Rafael Garcia, researcher at ISAE in Toulouse, and first author of the study.
Futura: How did you distinguish the impacts of meteorites among all the earthquakes recorded by Cess?
Rafael Garcia: First, Seis felt seismic wavesseismic waves But he also heard the sound of the explosion through the rotation of the Earth imposed by the shock wave as it reached the sensor. It’s a bit like the explosion of the AZF plant. People felt two explosions because at first they felt the ground shaking and then they heard the sound of the explosion.
Futura: How did you manage to accurately locate the drilling?
Rafael Garcia: We used this time interval between the arrival of seismic waves and that of Sound wavesSound waves Determines the distance between the Seis and the place of impact. Then, to find out which direction the impact was in, we examined the deformations of the ground under the influence of the sound wave. For accurate localization, they were supposed to be modelsatmosphereatmosphere Mars reproduces well sound speedssound speeds and the windswinds, which we know very well today. So we gave a location, and then the CTX filming team [caméra de contexte – Context Imager, du MRO] Take pictures there.
They did not always find craters directly, but more dust that was kicked up on impact, which covers a larger area. Once you find this blast area, They took accurate pictures 20 cm away from PrecisionPrecision With HiRise camera to determine the exact size of the pits.
Futura: So it was necessary to conduct several investigations for this study
Rafael Garcia: The nice thing is to be able to locate with a single instrument capable of recording both seismic waves and sound waves, and then to have all this battery of imaging devices that can take pictures with a resolution of 6m to 20cm. It is nice to see in this study the integration of tasks. Without it, nothing would have been possible.
Futura: Did this method of detecting influence have other precedents?
Rafael Garcia: Yes, once in Germany. During a gas explosion, seismographs detected infrasound and showed that the polarization indicated the direction of the explosion.
Futura: So this study is the first of its kind to discover the effect using Seis?
Rafael Garcia: In fact. Seis is believed to have recorded other impacts, but we were unable to distinguish them from earthquakes. Now, we take all of the Seis data and look at the seismic events that result from the impacts. Perhaps the first recorded earthquake impact? We are not sure yet.
Futura: So this is a new science goal that has been achieved for Seis?
Rafael Garcia: Yes, that wraps up the success of the Seis mission a bit. This was one of the scientific goals still to be achieved, and it is not completely independent of others because so far we have tried to find out both the soil substructure and the source of the waves with the same sensor. By separating the source [dans le cas d’un impact, Ndlr]we can photograph a file ShellShell Martian. We also verified that current models correctly predicted the arrival of waves.
Futura: So it’s not necessary to know the Martian crust very well to do this kind of experiment?
Rafael Garcia: Yes and no, we started with the assumption that we know the relationship between P-wave velocities and S-wave velocities. We didn’t really need the speed of P-waves because they are the most distance-constraining acoustic regions since they propagate slowly. So yeah, we’ll have better pictures of the internal structure, especially around Insight, and especially the cortex. Since the effects are close, we instead shoot the first 20-30 kilometers [de profondeur].
Futura: Is this also the first time ultrasound has been detected on Mars?
Rafael Garcia: Yes, that sounds very low repeatrepeat that scattered through the Martian atmosphere and were used in paper to depict the structure of the atmosphere.
Futura: What are the future mission applications?
Rafael Garcia: We can now determine the relationships between collisions and seismic waves: for such a crater size, I would have such energyenergy emitted by earthquakes. We will know better how many seismic waves the impacts produce and we will be able to know the impact recording capabilities of a future seismometer, such as those that would be on the Moon for example.
Futura: Could a similar process be used on the Moon?
Rafael Garcia: There is no sound wave on the Moon because there is no atmosphere, but with the various probes orbiting it, we will be able to image the craters that are there with seismographs. There is also detected flashflash Effect. When an object impacts the surface, it creates a small shape lightlight So short DurationDuration that can be observed from the Earth or from the orbit of the moon. It will also be a good way of packing Astronomy scientistsAstronomy scientists Amateurs, by observing the flashes on the Moon, will help the seismometer provide information, such as the exact time of impact.
Futura: So could it be used for the safety of manned missions to the moon?
Rafael Garcia: As for the Moon, we know very well the impacts of large meteors, but not many small ones, and this poses a significant risk for manned missions. It is in particular the micrometeoroids whose flux is not well known because on Earth, it burns instantly in the atmosphere.
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