Traces of water, conditions for life and disaster: what Curiosity learned in 10 years on Mars

10 years ago in early August, the Mars Research Laboratory jet lander

landed on the surface of the planet.And equipped with scientific instruments, a robot the size of a car began its journey to Mars. He had to find evidence that, billions of years ago, the Red Planet had the conditions necessary to support microscopic life.

The rover was originally supposed to serveonly one Martian year (686 Earth days). But despite signs of wear and tear, the rover is about to begin an exciting new chapter of its mission and climb the Martian mountain, according to NASA.

Proof of the existence of water

Immediately after landing, the Curiosity roverdiscovered smooth, rounded pebbles that scientists believe once rolled downstream for a distance of several kilometers. The analysis showed that such structures could have formed in a river, the depth of which ranged from several tens of centimeters to a meter.

Later, when the research module gotto Mount Sharp, scientists have discovered that several hundred meters of the rock surface is petrified silt that has formed at the bottom of small lakes. Researchers believe that rivers and lakes have filled Gale Crater for at least tens of millions of years.

Further discoveries only confirmed the firstfinds. Apparently, water has existed on Mars for a long time, long enough for the formation of life. For example, in a recent study, scientists found chemical traces of long-term exposure to groundwater in bedrock from Gale Crater.

Dry river stream on Mars

Enlarged image of the ancient riverbed. Rocks on Mars (left) and rocks from a dried-up river on Earth (right)
Images: NASA, JPL-Caltech, MSSS

Was there life on Mars?

This is still unknown.No traces of dinosaurs or other large life were found on the Red Planet, apparently, if life once existed on Mars, then it did not have time to develop beyond simple microorganisms.

It is known for certain that the conditions on early Mars werefavorable for the development of living organisms. Curiosity has found sulfur, nitrogen, oxygen, phosphorus and carbon, key ingredients necessary for life, in a powder sample recovered from Sheep's Bed mudstone in Yellowknife Bay. Clay minerals and a small amount of salt were also found in the sample, suggesting that fresh, possibly drinking water once flowed here.

Despite confirmation of favorable conditions andnumerous samples, life on Mars has not yet been found. Scientists from NASA this year suggested that the reason is that the missions are looking for in the wrong places. A new study has shown that under the influence of solar radiation, amino acids in the upper layers of regolith on the Red Planet decay. This means that traces of organic life must be sought at a depth of more than 2 m.

First detection of organic carbon

In late 2014, NASA scientists confirmeddiscovery of organic carbon on the surface of Mars. It is part of the complex molecules that are the building blocks for living cells. Organics were found at once in several samples obtained by the rover on Mount Sharp and on the plains surrounding it.

This discovery also does not confirm the presence orpast existence of life on Mars. But it says that once there were all the original "ingredients" for life. In addition, the find showed that the conditions on Mars make it possible to preserve organic matter.

First, the rover recorded a tenfolda surge of methane, an organic substance, in the atmosphere around a rock sample. Chemical analysis of the powder obtained from this material confirmed the presence of other carbonaceous substances. Unfortunately, the rover's limited capabilities make it impossible to accurately identify which molecules were found.

Scientists will be able to better study the chemical composition after samples of Martian soil are brought to Earth.

The first sample of rock drilling. Image: NASA, JPL-Caltech, MSSS

Active methane in the atmosphere

Tunable laser spectrometerequipped with Curiosity, in 2013 for the first time detected seasonally varying background levels of atmospheric methane. The device's sensors showed that in a few months from the end of 2013 to the beginning of 2014, it increased 10 times.

The discovery of methane on Mars was a milestone inexploration of the planet, because it can be produced, for example, by living organisms or as a result of chemical reactions between rock and water. It is not yet known what exactly leads to the formation of methane on the Red Planet and why its amount is constantly changing.

For example, in 2013, Curiosity sensors showed that the average concentration of this gas in the atmosphere was about nine parts per billion, and in 2019 there were already three times more.

Possible sources of methane. Image: NASA, JPL-Caltech

Another amazing discovery is thatAtmospheric methane appears to appear at night but disappear during the day. The researchers made this assumption by comparing the data of the instruments of the rover and the space satellite Trace Gas Orbiter, developed by the European Space Agency.

Scientists believe that there is no wind on Mars at night,so Curiosity, which explores the planet's atmosphere in its "off-duty" time, detects traces of gas released from the soil. During the day, the Martian atmosphere is turbulent, and methane dissipates to such an extent that it becomes elusive even for the most delicate instruments. Therefore, the orbiter, which needs sunlight to operate, does not find traces of the gas.

Radiation dangerous to humans

Already in the process of flying to Mars,the research module made its first discovery. The instrument's radiation sensors have detected two types of radiation that pose a potential health hazard to astronauts in deep space.

One of them is galactic spacerays. This is a stream of particles thrown out by supernova explosions and other high-energy events outside the solar system. Others are solar energy particles associated with solar flares and coronal mass ejections.

Analysis of the data obtained by the rover will help design a manned mission to Mars in such a way as to avoid dangerous consequences for its participants.

The climate catastrophe that changed the atmosphere

A study by Curiosity is the firstshowed that Mars had a denser atmosphere in the past. This is evidenced by the isotopic composition of the main elements of the Martian "air" - hydrogen, carbon and argon.

For example, Curiosity discovered that the Martianthe atmosphere contains about four times the light stable isotope (argon-36) compared to the heavier one (argon-38). This means that Mars is actively losing its atmosphere and most of the lighter isotopes have been lost in the upper layers of the planet's gaseous envelope.

Thanks to this discovery, researchers have developed and launched a new mission into Mars orbit, MAVEN, which should answer questions about what happened and whether our Earth is waiting for a similar outcome.

Selfie of the Curiosity rover. Image: NASA, JPL-Caltech

For 10 years, the Curiosity rover has repeatedly performedhis main task - he showed that before on Mars there were all the necessary conditions for the existence of life. In addition, he has collected enough data to prepare new missions that will more specifically study various features of the Red Planet.

But do not put an end to the rover itself.In April 2022, NASA decided to extend the rover for another three years. During this time, he must climb the mountain and explore the sulfate-bearing layers, which provide a unique insight into the history of water on Mars.

On the cover: artistic image of Curiosity. Source: NASA, JPL-Caltech

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