Insight, all the discoveries of the NASA mission that will end in December

Insight

The Insight mission lasted just four years. And although the US lander has never moved from its landing site, a valley in the volcanic region known as Elysium Planitia since its arrival on Mars on November 26, 2018, its visit to the Red Planet has proved extremely fruitful. From there, in fact, he collected precious data on the Martian seismic activity, on the composition of the inner layers of the planet, on its disappearance of the magnetosphere and on the processes that gave life to both. Insight's short adventure is destined to end soon, because at the end of next December the mission will be officially declared over, due to the problems encountered by the solar panels from which the lander draws energy. On this occasion, we retrace the main stages of its history, and the incredible discoveries it has given us.

The mission

Insight is the acronym for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport. A rather explicit name on the purpose of the expedition: to study the interior of the red planet using seismic waves, heat flows and geodesy (an accurate analysis of the structure of the planet and its atmosphere). It is therefore a static research, which aims to collect information like an earthquake station. For this reason, unlike other Martian missions, it does not include a rover or some other vehicle, but simply a lander equipped with all the sensors necessary for observations.

Despite the relative simplicity of the undertaking, it was a relatively unfortunate expedition. Since the start, originally scheduled for 2016, and then postponed to 2018 due to problems with the seismograph. Bad luck did not abandon Insight even upon landing: at the moment of taking action it was in fact the turn of a scientific instrument, the Heat Flow and Physical Properties Package, a sensor for measuring the heat flow that should have been placed at a depth of about 5 meters, and which instead could not be used due to the excessive softness of the soil which prevented the drilling tools from operating correctly.

In the end, the generators also came to betray it. of energy: the lander is in fact equipped with large solar panels with which it recharges its batteries, which had to surrender to the tenacity of the Martian sand, which covered them, reducing the production of electricity by about 10 times. Not being equipped to solve the problem, and not having had the luck of other NASA probes that in the past have been cleaned up by sudden gusts of wind (the so-called dust devils), the lander is therefore destined to conclude its operations in December of this year. 'year. Net of the many problems, however, the American space agency has nothing to complain about, given that in its four years on Mars it has made it possible to obtain invaluable information.

I martemoti

Insight it was in fact the first space mission to be able to demonstrate the existence of martemoti, that is, of a seismic activity on Mars. The first Martian earthquake was recorded by the lander's sensors in April 2019, 128 days after landing. To date, it has recorded over 1,300, managing to establish the epicenter of the tremors in about fifty cases. Most of the martyrs identified by Insight come from a region of the planet called Cerberus Fossae, an area about 1,500 kilometers from the lander, which shows signs of intense volcanic activity over the past two million years. In fact, the infiltration of magma linked to the volcanism of the area should be the cause of the tremors. And although for the most part these are relatively mild earthquakes, with magnitudes between two and three (the lightest in many cases turned out to be ground vibrations produced by the enormous power of the Martian winds), the most recent reached instead a magnitude just under five, which means that a human explorer present in the epicenter area would have clearly felt the earth shaking under their feet.

The interpretation of the data collected during the earthquake, the most powerful never recorded outside our planet, for now they are awaiting publication. But it has already been confirmed that, which is rare on Mars, the marine motion generated what are called surface waves, extremely useful for studying the interior of a celestial body. Seismic waves also reverberated across the planet for over six hours.

Asteroids

Another type of tremor identified by Insight's seismograph relates to entirely different events. In fact, in September and December 2021 it picked up the vibrations caused by the impact of two meteorites, of sufficient power, in both cases, to produce craters over 130 meters in diameter. Knowing the place of their fall, the data collected made it possible to study the conformation of the planet's crust in the area that separates the lander from the craters. Demonstrating that the region north of the landing zone has a much higher density than that in which the lander is positioned, and thus confirming the presence of structural variations in the composition and density of the Martian crust.

Thanks to Insight's seismograph was also able to study the composition of the depths of the planet, revealing the characteristics of the crust, mantle and core. Three studies published in Science last year analyzed each layer separately. Revealing the presence of a thinner than expected crust (between 20 and 37 kilometers), an underlying mantle that reaches up to about 1,500 kilometers deep, and therefore a liquid core (unlike Earth's), with a radius of 1,873 kilometres . The detailed information on the three layers will also allow us to understand more precisely the processes that led to the formation of the planet, as well as its evolution.

The magnetosphere

Among the characteristics that have contributed to make Mars the lifeless desert we know today, the main one is the absence of a magnetosphere, which (as happens on Earth) would have protected the atmosphere once present on the planet, maintaining on the surface conditions potentially suitable for the development of life . As we said, in the past the conditions were very different, and Insight has allowed us to confirm this. The lander is in fact equipped with the first magnetometer ever transported to the red planet, which made it possible to identify "ghost" traces of the planet's now disappeared magnetic field. In fact, the collected data reveals a strong magnetization in the rocks of the area.

And since the rocks on the surface are too young to have been magnetized by the ancient magnetic field of Mars, the scientists believe that they are rocks kept in the depths of the Martian crust, over 60 meters deep, magnetized in the distant past, before changes in the dynamics of the core and mantle of Mars led to the disappearance of its magnetosphere. In between discoveries, Insight also collected an incredible amount of data on the Martian weather, and on the sounds that can be heard on the surface of Mars. For this reason, when the mission is, in all likelihood, declared over on December 31, NASA will certainly not be the time for regrets.