The NASA Insight probe explores the inside of the planet

Monday night at 9 pm, it should be up to now: the NASA Insight spacecraft will have traveled about 485 million kilometers in 205 days since its launch on May 5 – and with 19,800 kilometers at the hour in the highest atmospheric layers of Mars penetrate. About 120 kilometers above its surface. In the "seven minutes of horror", as the US space agency Nasa calls it, the heavy probe of 608 kg at eight kilometers per hour must however slow down. It uses the fine atmosphere of Mars: the heat shield of the probe will heat up to 1500 degrees Celsius due to friction. Then a parachute unfurls, then twelve Landeraketen ignite – until the probe can finally sit on their three legs. This can be followed live at NASA via this link.

However, the landing process is not new: Insight is almost a twin identical to Mars' "Phoenix" probe, which had already been successfully launched in 2008 and had examined the ice cream. water and soil of our neighboring planet. Insight, on the other hand, pursues other goals: the end of nearly $ 830 million of the costly mission is almost on Mars under the skin. Insight means "Indoor exploration using seismic surveys, geodesy and heat transport". Or in German: internal exploration by seismic survey, survey and heat transport. Once Insight has landed, the probe will deploy a robotic arm to expose two measuring stations – from Europe.

One of them bears the name "Seis". The instrument looks like a small cathedral and is a mainly French project, but also involved in the Max Planck Institute for Solar System Research in Göttingen. Once placed on the surface, the seismometer measures even the smallest fractions of millimeter vibrations on Mars with the help of several sensitive pendulums. The objective is to know more about the internal structure of our neighboring planet: by badyzing the seismic waves propagating on Mars, the researchers hope to have new data on the nucleus, the surrounding mantle and the earth's crust. Similarly, scientists expect new discoveries about earthquakes, the activity of volcanoes and the frequency of meteorite impacts.

In contrast, the German Aerospace Center was responsible for developing the HP3 heat flux probe. It measures only 40 centimeters long, 27 millimeters in diameter and is almost a "mole": with the help of a hammer-hammer system, the probe penetrates the Martian soil and thus pulls a Tail-like measuring cable with temperature sensors. a thousandth of a degree are exactly. Within two months, the "mole" will be depressed five meters deep in the Martian soil. Every 50 centimeters, he pauses, heats up and measures how quickly the heat is absorbed by the Martian soil. The aim is to learn more about the properties of the rock, for example its degree of solidity or porosity, and to know if it is a good conductor of heat, such as metal, or a bad one like glbad . In the end, you want to extrapolate the data to the whole planet and make statements about how quickly the planet emits heat and its origin.

A third instrument, on the other hand, consists only of antennas: NASA records the shift in wavelengths of radio signals due to minimal fluctuations in the axis of rotation of Mars. This again reveals clues as to whether our neighboring planet is constructed as a hard-boiled egg with a solid core or rather as a raw egg with a liquid core.

Since capturing accurate data takes time, the mission is set up for two years. The probe is powered by two solar collectors with a total area of ​​seven square meters. In order to produce as much energy as possible, a landing site located about 600 km from the Rover Curiosity, near the Martian equator, was also chosen: Elysium Planitia. This vast plain without rocks or hills also offers ideal conditions for "watching" beneath the surface of the planet.

NASA is also trying something new with Insight. The probe sent two mini-satellites called Marco A and B the size of a briefcase during the trip. They reached Mars on their own trajectory. There, they must serve as a relay station for Insight. If the system succeeds, NASA will not have to wait more hours to get a first signal of life from the probe on our neighboring planet. On the contrary, the Marcos will be able to send data after only a few minutes. Future missions could then always start with their own CubeSats.

And why do you want to know more about the interior of Mars? It's not just about the red planet. Rather, we would like to know more about the formation of rocky planets when comparing data with the Earth. Basically, we understand the process: in the primitive solar system, rocks collided; they warmed up and merged with each other. It has become the nucleus of a planet surrounded by a mantle and a crust. After that, however, the planets developed differently. And you want to better understand this process with the help of Insight – so you can draw conclusions about possible distant lands around distant suns.