Mars rover Perseverance has landed

The Mars rover “Perseverance” will use its robotic arm to take rock samples and search for biological signatures.

NASA / JPL-Caltech

Late on Thursday night, the Mars rover “Perseverance” landed safely on the surface of the red planet. Landing on our neighboring planet is complex, so the venture, despite NASA having succeeded a few times, was anything but a sure success.

But this time too, luck and skill ensured a successful landing at NASA. Signals from the rover reached the control center exactly as planned on Thursday night, until finally, at 9:56 p.m., it was said with great relief: “landing confirmed.” Soon after, NASA engineers were able to present the first image in which the new rover captured a rather uncomfortable environment with onboard cameras.

Perseverance is the largest, heaviest and most complex rover ever to be sent to Mars.

“‘Perseverance’ is our robotic astrobiologist,” Thomas Zurbuchen, NASA’s Swiss chief of science, said in a webcast media talk in late January. For the first time, the US authorities sent one of their rovers to Mars with a very special task. After the previous missions were mainly focused on the search for favorable environmental conditions for life, now the focus is for the first time on the search for traces of previous lives.

Search for primitive life

This is a dream come true for astrobiologists. They knew for a long time that the red planet, today a lifeless, dusty and icy desert landscape, must have been much more attractive, covered by rivers and lakes. However, for at least as long, the researchers speculated that primitive life must have existed on the planet at that time. So far they have not been able to find any evidence of this. “Perseverance” – translated: perseverance or endurance – now you are ready to change that.

Before that, however, the vehicle, which weighs more than a ton, had to land safely on the planet. In view of the thin Martian atmosphere with its unpredictable winds, this is not an easy task: in 17 landing attempts to date, less than half of the probes reached the ground undamaged; only the Americans were successful. Zurbuchen, therefore, views the landing as one of the most difficult endeavors humanity has ever undertaken. And it says, “Success is not guaranteed.”

It is not surprising with the maneuver that “Perseverance” expected: the probe hit the Martian atmosphere at almost 20,000 kilometers per hour. Slowed down by air friction, the probe heats up to 1200 degrees Celsius. Open a brake chute and keep slowing down. At 320 kilometers per hour, the probe finally cuts its parachute and swings toward the target on eight downward-pointing brake motors. Then, 20 meters above the ground, let “Perseverance” lower to the surface with nylon ropes, like under a crane. The rover is supposed to land softly on Martian soil, at maximum walking pace.

Old lake as a landing site

Using very similar technology, NASA successfully brought its “Curiosity” rover to Mars nine years ago. However, many things were different this time: “perseverance” is not only more difficult, your landing site is also much more challenging. The mission administrators chose a dry lake for their search for life, which was once almost as large as Lake Constance. In it you can find remains of a branched and irregular river delta, sandy patches, boulders and steep cliffs. “This is a great place for science, but from a landing perspective I see one thing above all else: dangers,” NASA engineer Allen Chen, responsible for the landing, said beforehand. “It will be a great challenge.”

Those responsible for the mission, which cost almost 2,500 million Swiss francs, cannot intervene; Mars is too far away for that. Given a distance of 180 million kilometers from Earth, each signal takes more than eleven minutes to reach the control center. With the help of cameras, radars and stored maps of Mars, the mother probe of “Perseverance” determined its position independently. She should decide for herself when to open the parachute and at what target the brake rocket should be aimed.

After the happy landing, “Perseverance” won’t start looking for traces of life right away. Rather, a technological experiment is planned first: the first powered flight in the atmosphere of another planet. NASA engineers have prepared a small helicopter called “Ingenuity” (German: ingenuity). It is supposed to show that, in principle, flights are possible in the thin Martian atmosphere, which corresponds to only one-hundredth the density of Earth’s air. And it should show that helicopters can one day support tried and tested explorers – or even replace them.

Analysis with camera, laser and X-ray machine

There is still a long way to go. Once the helicopter blows off steam, “Perseverance” must go on a long journey. NASA researchers have planned a distance of 25 kilometers for the next few years: across the bottom of the ancient lake, through the river delta and along the beach, where waves once lapped up the shore. The rover is supposed to be on the lookout for sediment that may once have been created by microorganisms. The model is so-called stromatolites, lumpy lumps of lime that were formed by bacteria 3.5 billion years ago and are still found in many places.

The rover can analyze its samples with a microscope camera, a laser and an X-ray machine. Earth-based astrobiologists don’t want to leave it that way, they want to apply the full potential of their laboratories to potential findings. Therefore, “perseverance” must drill through some of the rock and store these drill cores, each the size of chalk, in a container. A few years later, the plan is for another rover to come and pick up the box. Then a rocket will launch the samples into orbit around Mars, and another probe will take them there and bring them back to Earth, sometime in the next decade.

“That sounds complicated and it is,” says Lori Glaze, NASA’s head of planetary research. However, above all, the project is long. And you need something that undoubtedly brings with it “perseverance”, even in name: perseverance and perseverance.

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