A groundbreaking revelation suggests NASA's Viking missions in the 1970s might have unknowingly destroyed potential evidence of microbial life on Mars.
The Viking landers, which were the first US spacecraft to touch down on the Martian surface, conducted experiments to detect life. However, scientists now believe the methods used in these experiments may have inadvertently killed any microorganisms present in the soil.
NASA's Viking Experiments May Have Destroyed Martian Life Evidence
Astrobiologist Dirk Schulze-Makuch from the Technical University Berlin recently revisited the Viking data, raising concerns about the impact of these tests on potential Martian life.
The experiments assumed that life on Mars would behave similarly to life on Earth, requiring significant amounts of liquid water to thrive, Science Alert said.
Soil samples were treated with water and nutrients, aiming to detect signs of metabolism, growth, or reproduction.
However, Mars is much drier than Earth, and any microbial life on the planet may be highly adapted to survive in extremely arid conditions. Schulze-Makuch explained that exposing such organisms to large amounts of water could overwhelm and effectively "drown" them.
He compared it to rescuing a dehydrated person in the desert by placing them in the middle of the ocean—a well-intentioned act with disastrous consequences.
The Viking landers conducted four main experiments. One of these, the gas chromatograph-mass spectrometer (GCMS), heated soil samples to analyze their composition but may have incinerated any organic material.
Another experiment, the pyrolytic release test, detected signals of possible life, which were stronger when less water was added. This result supports the idea that Martian microbes might be adapted to dry environments, utilizing salts to extract moisture from the atmosphere.
Martian Microbes May Thrive on Salts, Scientist Challenges Old Theories
Schulze-Makuch's hypothesis, first proposed in 2007, suggests that Martian life might incorporate hydrogen peroxide to survive the planet's harsh environment.
He argues that the Viking results could align with this theory and highlights the need to refine future experiments based on Mars' unique conditions.
As NASA and other space agencies plan new missions to the Red Planet, Schulze-Makuch urges a shift in strategy. According to Business Standard, instead of "following the water," scientists should focus on locating hydrated and hygroscopic compounds like salts, which might harbor dry-adapted microbial life.
Nearly 50 years after the Viking missions, this revelation underscores the importance of designing experiments that respect the ecological realities of extraterrestrial environments. A dedicated life-detection mission, informed by these insights, could finally answer the question: does life exist on Mars?
