A new approach to the rapid search for life can uniquely detect it with just one tool. It is already on board both active American Mars rovers. However, NASA may not want to take advantage of this opportunity.
NASA actively pursued the task of detecting extraterrestrial life in the 1970s and 1980s. Viking devices conducted a number of analyses for this purpose, most of which gave a formally positive result, although most scientists concluded that it was false. However, some scientists believe otherwise and believe that life on the Red Planet was found just then.
That situation highlighted the difficulty of finding life with a limited amount of scientific equipment. While in most cases a biologist can find a living organism using only a microscope, automation does not have such capabilities. She needs as a sign something that does not require intelligence, which can be detected without mental effort.
Therefore, the authors of the new work, which they published in the npj Space Exploration edition, tried to find a simpler and tougher marker of life. They are intact polar lipids, a special category of lipids from the cell walls of many terrestrial bacteria and archaea. They found that pyrolytic gas chromatography mass spectrometry can confidently detect even very small traces of these molecules in heated material containing live or very recently dead bacteria, archaea, or eukaryotic cells.
The result of the heating was monoglycerides. These molecules are quite well detected, and with a low error rate, and there will be no ambiguities in the interpretation of their detection.
It is important to note that there is a device for such spectrometry on board Curiosity and Perseverance, NASA's active Mars rovers. Theoretically, this means that the equipment already available on the fourth planet can be "taught" to unequivocally find life there. Since intact polar lipids disintegrate literally a few hours after the death of a living organism, such tests will not be able to mistake an ancient Martian organism for the one that lives on Mars today.
"Curiosity has been on Mars for 13 years, but who says you can't teach an old dog new tricks?" one of the authors of the paper noted in comments to the media.
From a practical point of view, this is important, since the preparation and sending of new scientific equipment to Mars is a matter that takes many years. It will be possible to use the devices already deployed there in just months. Unfortunately, despite the optimism, there is a serious possibility that NASA will not want to use this method for current Mars rovers.
Space experts, including former NASA employees, have already noted that the agency has avoided sending automatons capable of finding modern life there to Mars since 1976. And those vehicles that were nevertheless sent to the fourth planet deliberately carried equipment to detect existing life — only traces of the past. This is a conscious policy of the organization, the reasons for which are summarized in the links above. Staying within its framework, it will not be possible to use new scientific work. On the other hand, it is difficult to rule out that NASA will abandon its policy of avoiding the search for modern life on the fourth planet.
