The landing is the most intense phase of the Perseverance mission which is scheduled to arrive on the Red Planet on February 18 at approximately 9:55 am KST. Especially since the maneuver is in automatic mode because Mars is far away from Earth (communication takes about 11 minutes) for this to be directed from the JPL command center. The EDL (“entry-descent-landing”) maneuver starts at 20,000 km / h on top of the thin Martian atmosphere and ends 7 minutes later with the rover stationary on the Martian surface. The lack of time has been described by NASA as a “7-minute panic”.
Ten minutes before it enters the atmosphere, the spacecraft leaves its cruise phase, which consists of solar panels, radios and fuel tanks used on a flight to Mars. Before entering the atmosphere, the vehicle fires small thrusters at the rear to re-shield itself and ensure that the heat shield is forward facing.
When the spacecraft enters Mars’ atmosphere, the drawn output slows it down considerably, but these forces heat it up considerably. The maximum temperature reaches 80 seconds after atmospheric penetration, increasing to about 1,300 ° C on the outer surface of the heat shield. As it begins to descend into the atmosphere, the spacecraft encounters more or less dense pockets of air, causing it to deviate from its trajectory. To compensate, it drives small thrusters on its rear hull that adjust its angle and lift direction.
The heat shield slows the firmness to 1,600 km / h, at which point supersonic parachutes are deployed.
Descending stages. Sincerely: NASA / JPL-Caltech
Zero on landing
Twenty seconds after the parachute is deployed, the heat shield separates and collapses. The rover is exposed to Mars’ atmosphere for the first time, and key cameras and equipment can start locking on the bottom surface. Its landing radar bounces signals off the surface to determine its height.
Using a special camera to quickly identify surface features, the rover compares them to an on-board map to determine where it is going.
In thin Martian environments, the parachute can only slow the vehicle down to about 320 kilometers per hour. To achieve safe speed, the fixture must be released from the parachute and activate the “Sky Crane” or descent stage. It is a type of jetpack with eight engines mounted on the ground. Once it is about 2,100 meters above the surface, the rover detaches from the rear hull and ejects the engine for the Decent stage.
The sky crane leaves perseverance. Sincerely: NASA / JPL-Caltech.
Sky crane maneuver
Twelve seconds before touchdown, about 20 meters above the surface, the Sky Crane lowers the rover onto a set of 6.4 meters of cable and in the meantime the rover unlocks its wheels in a closed position. As soon as the rover senses that its wheels have touched the ground, it quickly cuts the cable connecting it to the descent stage. This allows the Sky Crane to pull up quickly to make its own, uncontrolled landing at a strongly safe distance. Once free, the rover will spend many hours ensuring its integrity and these devices.