After a seven-month trip, NASA's InSight probe is about to reach Mars and, if the contact takes place, embarks on an unprecedented mission to map the interior of the planet.
The lander will point to one of the most boring parts of the planet's dusty surface, Elysium Planitia, a vast lava plain that the US space agency. UU It calls "the largest parking lot on Mars." The flat, rock-free extension was considered the perfect place for InSight to record the tremors triggered by "Mars earthquakes" and to measure the heat flow in the upper layers of the planet.
The $ 814 million (£ 633 million) mission will help scientists understand the Martian nucleus, cortex and mantle, enabling them to know for the first time how the planet formed at the dawn of the solar system 4.6 billion years ago.
The landing of a probe on Mars remains a sensitive issue for rocket scientists: only 40% of missions have been successful. NASA is the only space agency that has managed to land on the planet, most recently in 2012, when the Curiosity rover was brought to the surface by an "aerial crane". In 2016, the European Space Agency attempted to put a lander on Mars, but the Schiaparelli probe blew out its retro rockets too early and crashed to the ground.
The InSight lander is expected to land around 8 p.m. GMT on Monday, and it will be necessary for several critical steps to work perfectly. The spacecraft will launch into the thin Martian atmosphere at 13,200 mph, deploy a parachute and fire 12 retro-propellers to cushion its landing. NASA calls the phase of entry, descent and landing of its missions to Mars the "seven minutes of terror". The confirmation of the landing will be sent back to Earth through two experimental cube satellites that have tracked the probe to its destination.
On the surface of Mars, InSight (for Internal Exploration using Seismic Investigations) will use a set of instruments to study the internal structure of the planet. A seismometer deployed by a robotic arm will act as an ear to the ground and hear the tremors produced when the faces of underground rocks slide into each other along geological faults. Bruce Banerdt, the principal mission scientist at NASA's Jet Propulsion Laboratory in California, expects InSight to record from a dozen to 100 tsunamons of magnitude 3.5 or higher during the two-year landing module mission. The seismometer is so sensitive that it can detect vibrations smaller than the width of an atom.
Another instrument on board the lander is a spear-shaped heat probe, which will be inserted vertically into the ground and measure the speed at which heat escapes the planet. The interior of Mars is still cooling from the hot days of its assembly in the solar system, and when the heat leaves the planet, the surface shrinks and wrinkles.
A third InSight experiment will explode two radio antennas in the lander. Mission scientists can use them to track the position of the lander with extreme precision, and thus deduce how much Mars teeters on its axis as it orbits around the Sun. The wobbling amount reflects the size of the nucleus of the planet and whether it is molten or solid.
Lori Glaze, the interim director of NASA's planetary science division, said: "Once InSight is established on the red planet and its instruments are deployed, it will begin to collect valuable information about the structure of the deep interior of Mars, information that will help us understand the formation and evolution of all rocky planets, including what we call home. "