NASA’s Viking was the first American spacecraft to land on Mars and returned images of craters, huge volcanoes and gigantic canyons. In the 1970s, NASA launched two identical robots – Viking 1 and Viking 2, each equipped with landers and orbiters – to head for the Red Planet. After the mission, NASA announced that they found no signs of life. But one scientist is almost certain they may have unwittingly stumbled upon alien life and dismissed it, Live Science reported.
“After landing on the Red Planet in 1976, NASA’s Viking landers may have sampled small, dry, hardy life forms hiding inside Martian rocks,” suggested Dirk Schulze-Makuch, an astrobiologist at the Technical University of Berlin in an article on Big Think. He said he and fellow scientist Joop Houtkooper are reevaluating the results of Project Viking.
“If these extreme life forms had existed and continued to exist, the experiments conducted by the lander could have killed them before they were identified because the tests would have overwhelmed these potential microbes,” Schulze-Makuch wrote, according to Live Science. He added that microbes that survive in similar conditions live on Earth and could therefore also live on Mars.
The Viking robots performed four experiments on Mars: a gas chromatograph mass spectrometer (GC-MS) experiment for organic or carbon-containing compounds in Martian soil; a Labeled Release (LR) experiment to test metabolism by adding radiotraced nutrients to soil; a pyrolytic release (PR) experiment for carbon fixation by potential photosynthetic organisms; and a gas exchange experiment to monitor gases.
The results of these experiments were mixed. In both the LR and PR experiments, they found small changes in gas concentrations, which indicated that some metabolism was taking place and therefore there could be life on Mars. GC-MS also found traces of organochlorine compounds. However, the results were rejected by scientists who thought that the experimental instruments had been contaminated by cleaning solutions that contained chlorine. And when the gas experiment gave a negative result, the idea of ​​life on Mars was avoided once and for all.
But Schulze-Makuch had other ideas, since most of these experiments required adding water to Martian soil samples. Using the example of a 2018 study on the Atacama desert, which found that microbes die due to the presence of water, he hypothesized that the use of water in these experiments must have killed the microbes that were hiding inside the soil samples taken from the red planet.
Additionally, Alberto Fairén, an astrobiologist at Cornell University and co-author of the 2018 study, told Live Science that he “totally agrees” that adding water to the Viking experiments may have killed potential hygroscopic microbes that could have harbored signs of life on Mars.
Schulze-Makuch, Houtkooper and Alberto were not the only ones who believed that life had been discovered on Mars. One of the principal investigators of NASA’s experiment that sent the Viking landers to Mars, Gilbert Levin, has repeatedly said over the years that the Viking experiment revealed life, according to CNN. Levin published an article in Scientific American stating, “I am convinced that we found evidence of life on Mars in the 1970s.”
“NASA has already announced that its 2020 lander will not include a life detection test,” Levin wrote, “in accordance with well-established scientific protocol, I believe efforts should be made to conduct life detection experiments on the next mission to Mars . possible.” He proposed that the LR experiment be repeated on Mars. “(In the 1970s) NASA concluded that LR had found a life-mimicking substance, but not life… inexplicably, in the 43 years since Viking, no none of NASA’s subsequent Mars landers carried a life detection instrument to follow up on these exciting results.”
However, recent NASA missions provide somewhat conflicting results. In 2007, NASA’s Phoenix lander, successor to Viking, found traces of perchlorate on Mars. Perchlorate is toxic to plants and microorganisms. On the other hand, NASA’s 2020 Perseverance rover found organic matter on Mars in the form of sediments that suggested the existence of “salt lakes” somewhere on Mars. This is possible because, according to NASA, Mars was a wet planet billions of years ago and also had a lake. However, despite all these hypotheses, there is currently no solid evidence to suggest the existence of life on Mars.