Whoopsie, NASA Might Have Accidentally Killed Life on Mars
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When the Viking 1 lander send down twin landers to study Mars in 1976, the results returned a negative result for the possibility of microbial life.
However, for years, scientists have argued that the Viking's experimental techniques might’ve killed hygroscopic microbes living on Mars with too much water.
While impossible to know for sure, this theory could be proven true or false if NASA sends another dedicated mission to detect biological life on Mars.
For nearly 50 years, NASA has been exploring the possibility of microbial life on Mars. That investigation began with the Viking 1 lander, which entered orbit around the Red Planet in the mid-1970s. The spacecraft released twin landers that eventually touched down on the surface of Earth’s celestial neighbor—the first U.S. spacecraft to pull off the feat.
These landers’ collective mission was a biological one: to detect life on another planet. The results that the landers sent home were… mixed, to say the least. Some experiments showed positive signs, while others—particularly their gas exchange experiment—did not. However, one instrument designed to detect organic compounds discovered chlorinated organics.
Scientists at the time dismissed this result as Earth-based contamination (which, according to NASA, was likely due to cleaning fluids). But experts have learned a lot about Mars over the intervening years. Curiosity and Perseverance, for example, have both confirmed the existence of indigenous organic compounds on Mars. And now, in recent years, some scientists—including astrobiologist Dirk Schulze-Makuch from the University of Berlin—suggest that the Viking landers may have accidentally killed life on Mars by applying too much water when examining samples. Schulze-Makuch elaborated on this theory in a recent essay published in the journal Nature, he previously argued this claim in a Big Think piece published last year.
The main problem with Viking’s techniques, according to Schulze-Makuch, is the assumption that life on Mars would behave like life on Earth, and would thrive in the presence of water. But he argues that microbes could’ve adapted to the hyperarid conditions on Mars, and that the water used in some of the analyses could’ve caused them more harm than good.
“Now let’s ask what would happen if you poured water over these dry-adapted microbes” Schulze-Makuch wrote for Big Think back in 2023. “Might that overwhelm them? In technical terms, we would say that we were hyperhydrating them, but in simple terms, it would be more like drowning them.”
One of NASA’s governing strategies in finding evidence of life on Mars is a “follow the water” approach. But that may stem from an Earth-centric bias toward the wondrous, life sustaining molecule. It could be possible to also discover microorganisms near hygroscopic compounds, or salts, as well. Schulze-Makuch advocates that future NASA experiments need to be more tailored to these considerations in the hope of finding life that thrives without access to immediate water.
Scientists have long speculated that the Viking missions found more than previously believed, and NASA will likely need to send another dedicated life-detecting mission to test these hypotheses and prove—once and for all—if Mars is truly devoid of life.
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