Does Mars have any moons

Nasa lands on Mars: In search of life

Illustration of the Nasa rover “Perseverance” landing safely on Mars Photo: NASA / imago

On Thursday the NASA rover "Perseverance" lands on Mars. So far, no extraterrestrial life has been discovered - but the evidence is increasing.

From Berlin, February 17, 2021, 4:30 p.m.

The weather forecast for Jezero crater on Mars? Gaining importance. Because on Thursday, February 18 at 9:50 pm German time, NASA lands with its next big thing, the “Perseverance” rover.

Well, the weather can at least be reliably assumed: the next thermometer is, roughly estimated via Google Mars, 3,200 kilometers away, in the stomach of the Mars veteran "Curiosity". It has been rolling around in the Gale crater for over 3,000 sols, i.e. Mars days of 24 hours and 39 minutes each. It is a pleasant late summer there with temperatures of down to minus 73 degrees at night.

Curiosity is slightly south of the equator, Perseverance will land slightly north of the equator. But the temperatures should be similar there, same climatic zone, only quite windy. And in the dunes there are probably the debris of the British probe Beagle 2, which crashed on landing in 2003.

The rover “Perseverance” is scheduled to land on Mars on February 18 at 9:50 pm German time Photo: JPL-Caltech / NASA

Since 1960 there have been 49 missions to Mars, including the failed probes and the two United Arab Emirates and China probes that recently entered orbit. Politically it is always about the vanities of nations to prove their engineering skills, scientifically about the eternal question: Is there such a thing as extraterrestrial life?

Not the smallest microbe

Nothing has been discovered yet, not the smallest microbe. But the evidence that something was or is on Mars is increasing thanks to generations of scientists whose job is this search.

Exactly four missions have and had the ability to prove life on board - or the remains of it that have slumbered in the ground for billions of years: the two Viking probes from NASA in the 1970s; Curiosity, which has been drilling small holes, taking soil samples and transmitting data since 2012; and after Perseverance "Rosalind Franklin" is to come in 2023, the rover of the European space agency ESA and the Russian Roskosmos.

"Rover" is an understatement at Perseverance, the thing has the dimensions of a small car. Three meters long, a tonne, the weather station on board is sophisticated. A bunch of cameras in my head that take 360-degree photos, 3D and in color, with zoom, plus microphones to record the muffled sound of the thin Martian atmosphere. A bread box-sized device with a folding basket design called the Moxie is to be removed from the CO2 the Martian air, of which it consists of 96 percent, extract oxygen. Just to show that it is possible.

By the end of the 2030s humans to Mars

On board the Perseverance rover: Ingenuity, a helicopter that is supposed to fly around autonomously Photo: JPL-Caltech / NASA / ap

Finally, Barack Obama promised to send people to Mars by the late 2030s. The landing system from Perseverance, with jetpack and ground penetrating radar, spontaneously and independently decides where exactly to drop the rover. Ingenuity is also on board, a helicopter with a 1.2 meter wingspan that is supposed to fly around largely autonomously. To show that this is possible in the thin Martian atmosphere.

Above all, the rover is one thing: a demo mission for the latest space technologies, writes NASA. In terms of the search for life, another part of the mission could be the breakthrough: Perseverance is supposed to take soil samples and seal them. The European space agency ESA is supposed to collect them with a robot sometime by 2031 and bring them to earth.

Daniel P. Glavin, astrobiologist, is part of the NASA team that is supposed to take the soil samples. He is Vice Director of Research Strategy in the Curiosity Team and has previously spent a few weeks looking for Mars meteorites in Antarctica. Life on mars? “I am still optimistic. For me the question is not whether, but where there is life on Mars, ”he tells taz. Curiosity made "significant discoveries".

Mars veteran “Curiosity” has been rolling around the Gale crater for over 3000 Mars days Photo: JPL-Caltech / NASA / Reuters

It has now been proven: The Gale crater was a lake 3.5 billion years ago. And one with perfect conditions for life. Not too sour, not too salty, with all the important elements, says Glavin. Even before Curiosity, it was considered fairly certain that Mars was a twin of Earth in its early stages.

Life as a real plague

Caroline Freissinet from the French Latmos Research Institute is one of the scientists who has been bending over the data that Curiosity transmits to Earth for years. Before she turned to astrobiology, she also did research on the microbiology of New Zealand sheep. "If life has arisen on a planet, you can never get rid of it, it's a real nuisance," Freissinet says in the video chat.

The Gale crater was a lake 3.5 billion years ago Photo: JPL-Caltech / NASA / Reuters

Today Mars is very dry, is grilled by ultraviolet radiation, water on the surface has so far only been found at the North Pole, frozen. "It may well be that life originated on Mars and, when conditions worsened, it has retreated to the warmer underground and lives in small pockets of water, where it gets its energy from minerals," says Freissinet.

And then there is Gilbert Levin, who Freissinet and Glavin - they don't say that directly - probably gets a little on your nerves. Gil, as they call him, repeatedly debates with Glavin and Freissinet. The man is a jack-of-all-trades who has already patented a low-calorie sweetener and a remedy for type 2 diabetes and much more. He started engineering at Johns Hopkins University in 1941 and is still in the space business.

Levin claims to this day that, together with his colleague Patricia Ann Straat, he discovered life on Mars in 1976. Together with a handful of other scientists, the two of them repeatedly published new evaluations of the old data in reputable journals such as Astrobiology.

Viking probes on Mars

Back then, in 1976, the two NASA probes Viking 1 and 2 landed on Mars. Levin was the chief scientist of an experiment that was supposed to look for life: the Viking probes took soil samples, provided them with a nutrient solution, warmed them up carefully and checked whether something in the soil was consuming the solution and exhaling gases. And that happened over and over again. The rest of the data was contradicting itself. For NASA and a large part of the scientific community, that was far too thin for the big sensation.

Mars surface: a photo taken by Viking probe 2 in 1976 Photo: Ho New / Reuters

The taz asked Levin to conduct investigative research as early as 2017: "Why did NASA ignore the simple scientific principle of repeating the experiment from then in order to validate or discard it?" He recently wrote in an email to the taz Freissinet and Glavin told him that Curiosity discovered kerogen, a mixture of organic matter. This can only be explained by the disintegration of former life. For example, petroleum is a kerogen.

Caroline Freissinet almost sounds angry when you talk to her about Levin's claims. Apparently he turns the word around in her mouth: She told him that they had found evidence of so-called alkenes in the Martian soil in the curiosity data. These could once have been fatty acids found in living cells. But they could also just have come about by chance on primordial Mars. Levin makes the claim that NASA discovered fatty acids.

A "smelly, musty mud"

In all debates about life on Mars it is important to know: “Organic” substances are all types of simple or complex molecules based on carbon. Something like that can be found everywhere, including on asteroids. The same applies to kerogen, writes Glavin. Its existence is no proof of life.

Such organic matter could be a “stinking, musty mud”, but it was mouse dead, says Fred Goesmann. He is a physicist at the Max Planck Institute for Solar System Research and chief scientist of the MOMA, the instrument in the ESA rover Rosalind Franklin that could prove life. Start is in September 2022, landing on June 10, 2023. "The exact landing date somehow necessarily results from the orbital dynamics of the planets, I didn't understand it either," says Goesmann.

He doesn't know Levin personally, but he is certainly a likeable guy and definitely has one point: No matter what chemistry has been thrown together on earth, the Viking data has not yet been sufficiently reproducible without biological processes - but neither with.

“The search for life is a piece of puzzle work. As long as no hamster hops past us in front of the camera on Mars, nobody will believe that we have found anything anyway. ”And is Mars alive? It is important to him to find out. “But I tend to come from the handicraft corner and I'm happy when someone says to me: 'You can't do that on Mars,' and then it works,” he says.

Is there life on Mars? Microscope image of a Mars sample from NASA's Phoenix Mars Lander Photo: Ho New / Reuters

Traces of life at a depth of 2 meters

Goesmann speaks of a scientifically spectacular project that could complete the evidence of a once animate Mars: The Rover Rosalind Franklin will search the subsurface of Mars for life. “We'll end up where there was once loamy, clayey stuff,” he says.

This has been protected under lava for a few billion years since the early phase of Mars and only recently exposed for planetary time scales, perhaps 30 million years. "We dig up to two meters into it, traces of life could be preserved there," he says. "That would then be something different than this fuzzy chemistry that we have found so far."

The mass spectrometer on board the rover can examine the samples in such detail that possible order structures and patterns can be seen in the molecules that only leave life behind, no matter what it once looked like. Even if, according to NASA, Curiosity should not officially look for life, probably in order not to suspend the expectations of the mission too high: the old veteran could have found something like that too. But it doesn't. Not a “smoking gun when it comes to life,” says Glavin.

Perseverance, on the other hand, can search for chemical compounds by X-raying the Martian soil. But that only shows "how the stuff glows in the ground when it is irradiated," says Goesmann. Details that help in the search for life can hardly be found, he says.

Epochal search, decisive mistake

And the two space agencies Esa and Nasa probably made a mistake that was decisive for the epoch-making search when designing their two rovers Rosalind Franklin and Perseverance: If there is still microbiological life, it is most likely in the protected underground where Goesmann drills into it. It would be a dream if these deep soil samples were also sent to Earth for precise analysis, says Freissinet.

But that doesn't happen, Rosalind Franklin is too small to take the device for packing soil samples with her in addition to a drill: It is, completely ecologically, powered only by solar cells. On Perseverance, equipped with a powerful plutonium-238 battery, there was again no room for a drill with all the demo technology. So NASA only packs samples from the surface. The Europeans should then collect them with a completely new robot that has yet to be constructed. And so it happens that science will wait 10 years, until 2031, for soil samples from Mars to come to Earth - and they could say little because they come from the surface that has been grilled with UV rays.

Meanwhile, Gilbert Levin is involved in the "International Committee against Mars Samples on Earth" because he fears that extraterrestrial microbes could contaminate the earth. Glavin is more concerned that the samples will not arrive safely. Goesmann sees it this way: NASA has been announcing for 50 years that it will be creating Martian samples on earth in 10 years. Let's see. Maybe Elon Musk will take care of that too. He recently promised to send people to Mars in 2024.

Model of the "Rosalind Franklin" - the rover is being developed by the European space agency ESA Photo: Stephen Chung / imago

This is not a good idea for Goesmann: "As soon as people stalk Mars, it is irrevocably contaminated with terrestrial microbes," he says. And then the riddle of whether life arose on Mars independently of Earth might never be solved. But if that were the case, then it will probably also live everywhere else in space where the conditions are right: there should be up to 300 million Earth-like planets in our galaxy alone, the Milky Way.