NASA’s Perseverance rover to face ‘7 minutes of terror’ before landing on Mars

February 16, 2021 by No Comments

Following “seven minutes of terror” after it reaches Mars’ upper atmosphere, NASA’s Perseverance rover is expected to land on the surface of the red planet at 20:55 GMT on February 18. This is incredibly hard to do, with only about 40% of missions succeeding.

As a member of the team that built the European Space Agency’s Rosalind Franklin rover (we made the PanCam, the camera “eyes” of the rover), which will set off for Mars next year, I will be holding my breath during the landing. There’s so much at stake. Not only could the mission unveil some of Mars’ best-kept secrets, and be a key part of future exploration to return a Mars sample back to Earth, it could also have important lessons for landing Rosalind Franklin.

The appropriately named Perseverance soared into the Florida morning sky on an Atlas V rocket on July 30, 2020, in the midst of a global pandemic for Earthlings. This was the start of a nearly 500 million-kilometer journey to the red planet, with the car-sized rover, and a helicopter called Ingenuity, aboard.

Its destination is the Jezero crater – a 45km-wide basin, with an old, dry river delta, cliffs, dunes, and boulder fields – where it will search for signs of ancient, primitive life on the Martian surface. Of course, it’s not impossible it could find current life too if there is any. Perseverance will also collect samples that another mission will retrieve and return to Earth in the late 2020s. This will be the first attempt to take off from the surface of another planet.

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Landing sequence

The reason it is hard to land on Mars is that the atmospheric pressure is so low that spacecraft move through it at enormous speeds unless they are slowed down. What’s more, the landing has to be done autonomously, without real-time contact with Earth. The landing sequence for Perseverance is an improved, more accurately targeted version of the “Skycrane” technique, which safely landed NASA’s Curiosity rover in 2012.

The “seven minutes of terror” will start at 20:48 GMT when a protective “aeroshell” containing Perseverance, Ingenuity, and a descent vehicle called “Skycrane” enters the Mars atmosphere at 19,500 km/h. Just over a minute later, the aeroshell will reach its maximum outer temperature, 1,300°C, due to friction with the upper atmosphere. Luckily, the front of the aeroshell is a protective heat shield.

At 20:52, a 21.5-meter parachute will deploy, and the heat shield will be ejected. Two minutes later, the back part of the shell will separate too. The Skycrane, descending at 2.7 km/h and powered by eight throttleable retrorockets, will then lower the rover on 7.6m nylon cords, from about 20m above the ground. When its speed has slowed down to 2.5km/h and the rover touches the surface, the cords will be severed. At 20:55 GMT Perseverance should land while Skycrane flies off into the sunset to a safe distance.