The current generation of Mars rovers may have trouble confirming any signs of ancient life on the Red Planet because their scientific instruments aren’t up to scratch, according to research published February 21 in the journal. nature communications (opens in a new tab).
In the study, the researchers conducted tests on sedimentary rocks in the Red Stone region of Chile’s Atacama Desert, one of the oldest and driest deserts on Earth and a geologic analogue of ancient sites on Mars that two NASA rovers found. are currently exploring. The same team of researchers previously discovered that the Red Stone clays are inhabited by a previously unknown mix of ancient and modern microorganisms dubbed the “dark microbiome.”
Using four instruments that are on current or future Mars rovers, the team studied Red Stone samples and found them incapable of detecting organic material. Only genetic sequencing, a procedure that can only be done in a laboratory on Earth, was able to find evidence of microbial life in the samples, but even then, it was barely detectable.
Therefore, any ancient organic material and microorganisms that exist in the Martian rock record could be “difficult, if not impossible” to detect in their current locations with existing technology, the researchers concluded. The new research highlights that, apart from sending more advanced rovers to the Red Planet, the only way to demonstrate unequivocal signs of life on Mars is to send samples back to Earth for DNA analysis.
“The possibility of getting false negatives in the search for life on Mars highlights the need for more powerful tools,” said the study’s lead author. Armando Azua Bustos (opens in a new tab)research scientist at the Center for Astrobiology (CAB) in Madrid, said in a statements (opens in a new tab).
Therefore, scientists can develop more sensitive and complex instrumentation for Mars rovers or bring back samples to Earth. Each option carries risks and benefits, the authors added.
“You have to decide whether it is more advantageous to have a limited analysis capability on the surface of Mars to interrogate a wide variety of samples or to have limited samples to analyze with the wide variety of state-of-the-art instruments on Earth.” co-lead study author Alberto G. Fairen (opens in a new tab)planetary scientist and astrobiologist at Cornell University, said in the statement.
There are currently three rovers on Mars. NASA’s Curiosity rover landed in Gale Crater on Mars in 2012 and recently found its the best evidence so far for water and waves on the Red Planet. Since 2021, NASA’s Perseverance rover has been exploring an ancient river delta in Jezero Crater looking for signs of ancient microbial life in the rock record. The rover is currently preparing samples that will be collected by a spacecraft and returned to Earth for in-depth analysis, though the challenging mission is still in its early stages.
In May 2021, Curiosity and Perseverance joined China’s Zhurong rover, which touched down on the Utopia Planitia plain and quickly found evidence of water. That rover isn’t looking for signs of ancient life, though.
Meanwhile, the European Space Agency plans to launch its delayed ExoMars mission in 2028 to land its rover rosalind franklin on the clayey plain of Oxia Planum.
“This European rover will carry a drill with the unprecedented ability to reach a depth of 2 meters (6.5 feet) to analyze sediments better protected against the harsh conditions of the Martian surface,” Fairén said. “If biosignatures are better preserved at depth, which we hope, there will be more abundance and diversity, and better conservation of biosignatures, in those deep samples.”