After centuries of wondering whether Mars is (or was) home to life, humanity may finally get some real answers as early as the next decade. With the planned 2028 launch of its ExoMars rover, dubbed Rosalind Franklin, the European Space Agency (ESA) could detect past or present life in situ up to two meters below the surface of Mars. If so, he could lead NASA for at least two years in astrobiology.
NASA is counting on the mission to return samples collected by the Perseverance rover to shed light on the possibility of life on Mars. But at the earliest, these samples are not expected to reach Earth until 2033.
Until the late launch of ESA’s Rosalind Franklin rover, all bets were off. But the ESA rover has many advantages to claim. The heart and soul of the ExoMars rover is the MOMA (Mars Organic Molecule Analyzer), which was built in collaboration between Germany, the United States and France.
The ESA spacecraft is expected to land in October 2030. Unlike NASA’s Perseverance and Curiosity rover, the Rosalind Franklin rover will rely primarily on solar energy to power its instruments during its nominal mission of about seven months. In good weather, the rover should be able to travel 70 to 100 meters while collecting core sediment samples. It will start collecting data as soon as possible after landing.
Did Mars have an ocean?
In particular, the ESA rover could answer the question of whether Mars experienced a northern ocean, the only ocean thought to have existed on Mars. In fact, the ESA rover’s landing site could be in the southernmost region of Oxia Planum in this possible ancient ocean.
“As far as we can tell, the entire area up to the north pole of Mars must have been flooded by tens of meters of water,” explains Jorge Fago, ExoMars project scientist, in his Mars office. Holland.
About four billion years ago, microbial colonies likely lived in some kind of hydrothermal system beneath the surface of Oxia Planum. Since Mars is thought to have been very volcanically active at the time, ash from volcanoes would have fallen to the surface of the ocean. When Mars lost its water and dried up, these microbial colonies turned into microfossils preserved by this sedimentary ash. Subsequent cold temperatures below the surface also contributed to their preservation.
Once Mars lost its surface water, Fago says, it got very cold. When digging 30 cm below the surface, the temperature is minus 15 degrees Celsius.
MOMA must first vaporize the compounds it collects so that they can be detected by the device’s mass spectrometer. Mass spectrometers measure the chemical composition and mass of a particular substance in the gaseous state. To do this, MOMA will use thermal or ultraviolet laser pulses to convert the chemical species of the samples into the gas phase. These chemical samples will then be analyzed in the gas phase aboard the ship to determine if they are biologically promising, in terms of composition and distribution.
Instead of thermal heat, MOMA will use a laser to separate the most important organic compounds from the minerals they were originally bound to. This will allow the team to avoid contamination of the samples with perchlorates, colorless, odorless salts, which can be an unwanted by-product of the type of heat required to perform this type of sample analysis.
“I think the probability of finding organic molecules is on the order of 100 percent,” says Fago. The probability that we will find something that sparks life is about 50%. »
What is the biggest scientific challenge for WOAgri?
Analyze the results, said Fred Gossmann, MMA principal investigator and planetary scientist at the Max Planck Institute in Göttingen, Germany. He explains, “If the identification of molecules exhibits a bit of ambiguity, then the meaning of ‘life detected’ is nuanced. Optimists will claim to have seen evidence of life, while pessimists will carefully seek non-biological explanations.” “We need both sides to get a coherent interpretation,” he adds. »
Will WOAgri provide proof of life?
“Evidence” is a big word, declared Mr. Guzman. As for the semantics of a virtual press conference after the reveal, he believes that rather than saying “This was life,” you should read the official statements instead: Right now, the only explanation for our findings is life; We can’t imagine any other way to achieve our results. »
Will WOAgri be able to distinguish between past and present lives?
According to Mr. Fago, present life will be recognized by the quantity and good state of preservation of biomolecules. When organisms are metabolically active, they can repair radiation damage, so we will have access to a high concentration of biomolecules.
What about a past life?
“The spores would have been dead long ago; their cell membranes would have burst and their chemical guts would have spilled into the geological record,” Fago says. Depending on how they were buried, they could be preserved, he adds.
“If we happen to find relics from the past, we need to be able to identify lots of independent biosignatures and do so iteratively with different samples,” he explains.
In short, it is a matter of creating a set of independent biosignatures.
“The key is to build a body of evidence that cannot be explained by anything other than biology,” Fago concludes.
Translated article from the American magazine Forbes – Author: Bruce Dormini
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