The US space agency Nasa landed a new robot on Mars after a dramatic seven-minute dive on the surface of the Red Planet.
The InSight probe aims to study the deep interior of the world and make it the only planet – apart from Earth – that has been examined in this way.
Touchdown confirmation came in at 19:53 GMT.
It ended with an anxious waiting in which the robot transmitted a series of updates on his descent.
NASA's mission control at the California Jet Propulsion Laboratory (JPL) exploded when it became clear that InSight was safe on the ground.
The agency's chief administrator, James Bridenstine, celebrated what he called "an incredible day". President Trump had phoned to offer his congratulations, he told reporters. And JPL director Mike Watkins said success should remind everyone that "to do science, we have to be bold and we have to be explorers."
InSight is now sitting on a vast plain known as Elysium Planitia, near the equator of the Red Planet. Before landing, NASA called it "the largest parking lot on Mars."
The first picture of this landscape came back very quickly, in a few minutes. It showed a blurred fish-eye view of the robot's surroundings.
The image was taken through the translucent cover of a camera positioned at the bottom of the probe. The dust raised on the descent obscured much of the scene, but it was still possible to distinguish a small rock, one of the probe's feet and the sky on the horizon.
A later photo captured by a camera on the InSight topside was much clearer.
What happened at the landing?
Like all previous landing attempts on Mars, the Insight's surface race – the first attempt since 2012 – was a tense subject.
Step by step and meter by meter, the robot reported his progress.
He had entered the atmosphere faster than a high-speed bullet, using the combination of a parachute, parachutes, and rockets to make a smooth stop.
InSight's first critical task at landing was to deploy its solar panels, which were saved for descent.
The robot had to start generating power to operate its systems and heat equipment in the below-zero temperatures that persist in the Red Planet. Notice of panel assembly occurred seven hours after landing.
One of the great achievements of the InSight mission so far has been the role played by the two suit-sized satellites that were sent to Mars along with the robot.
It was these mini-spacecrafts, called MarCO A and B, that transmitted the probe signals back to Earth during surface diving. The duo cost less than $ 20 million and their technologies will now be much more prominent in future interplanetary missions.
And as if to underline their capabilities, the smaller satellites also took a picture of Mars.
"Having brought all InSight data successfully during its exciting entry, descent and landing (EDL) – what you see before is an image taken at 4,700 miles from Mars, about 10-15 minutes after EDL," explained MarCO . chief engineer Andy Klesh.
What's different about the InSight mission?
This will be the first probe to devote its investigations to the understanding of the interior of Mars. Scientists want to know how the world is built – from its core to its crust. InSight has three main experiments to achieve this goal.
The first is a package of Franco-British seismographs that will be raised to the surface to hear "Marsquakes". These vibrations will reveal where the rock layers are and what they are made of.
A "soft" system led by Germany will excavate up to 5m in the ground to take the temperature of the planet. This will give you an idea of how Mars is still active.
And the third experiment will use radio transmissions to determine very precisely how the planet is oscillating on its axis. Deputy project scientist Suzanne Smrekar uses this analogy: "If you take a raw egg and a boiled egg and spin them, they sway differently because of the distribution of liquid inside." And today we really do not know if the nucleus of Mars is liquid or solid, and how big that nucleus is. InSight will give us this information. "
Why do we need to know that?
Scientists understand very well how the interior of the Earth is structured and have some good models to describe the beginning of this architecture at the birth of the Solar System, more than 4.5 billion years ago. But Earth is a data point and Mars will give researchers a different perspective on how a rocky planet can be assembled and evolve over time.
InSight chief scientist Bruce Banerdt said: "The little details of how the planets evolve are what we find to make the difference between a place like the Earth where you can go on vacation and sunbathe and a place like Venus where you burn in seconds or a place like Mars, where you'll freeze to death. "
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