The US space agency (NASA) has released an animation showing how its one-ton Perseverance rover will land on Mars on February 18.
The robot is sent to a crater called Jezero, where it will look for evidence of past life. But to undertake this science, he must first touch slowly.
The sequence of maneuvers required to land on Mars is often referred to as “seven minutes of terror” – and with good reason.
Both have to go in a frighteningly short space of time, or the mission that will arrive will dig a very large and very expensive new hole on the Red Planet.
Moreover, everything is autonomous.
With a distance in the day of 209 million km (130 million miles) between Earth and Mars, every moment and every movement you see in animation must be controlled by the computers on board.
It starts more than 100 km above the planet Mars, where the Perseverance rover will meet the first fragments of the atmosphere.
At this time, the vehicle, in its protective capsule, travels at 20,000 km / h (12,000 mph).
In just over 400 seconds, the descent system must reduce this speed to less than 1m / s at the surface.
Most of the work is done by a heat shield.
As the capsule plunges deeper into the Martian air, it becomes super hot at over 1000C – but at the same time, the firing dramatically slows down the fall.
By the time the supersonic parachute unfolds from the back of the capsule, the speed has already been reduced to 1,200 km / h.
Perseverance will go through the 21.5 m wide parachute for just over a minute, still washing that entrance speed.
However, the most complex phases are yet to come.
At an altitude of 2 km and while traveling at 100 m / s – the Perseverance rover and “Skycrane” separate from the housing and move away.
Eight rockets then light up on the cradle to bring the rover to a floating position just above the surface. Nylon cables are used to lower the multi-billion dollar wheeled vehicle to the ground.
But it’s not really that yet.
When Perseverance detects contact, it must immediately break the cables or be dragged behind the crane as the cradle flies to free itself at a safe distance.
The sequence looks a bit like the one used to put NASA’s latest rover, Curiosity, on the surface of Mars 12 years ago. However, navigation tools have been improved to put Perseverance in an even more precisely defined landing area.
Touchdown is expected in the late afternoon, local time, on Mars – just before 21:00 GMT on Earth.
It is worth remembering that on the day of landing, the time required for a radio signal to reach Earth from Mars will be about 700 seconds.
This means that when NASA receives the message from Perseverance that it has hit the top of the atmosphere, the mission will already be dead or alive on the surface of the planet for a few minutes.
The robot will record its descent on the camera and with microphones. Media files will be sent back to Earth after landing – assuming Perseverance will survive.
Read our guides for Perseverance (also known as the Mars 2020 mission) – where to go and what to do.
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