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According to some scientists, NASA may have inadvertently eliminated any possibility of finding life on Mars during the 1970s Viking mission. While no definitive evidence of life has been found on Mars thus far, there are lingering questions regarding the methods used during these early explorations which may have hindered the discovery of microbial life.
During the Viking mission in 1976, the landers conducted a series of experiments that were designed to detect biosignatures in Martian soil. One of the experiments involved using a gas chromatograph-mass spectrometer (GCMS) to identify chlorinated organics in the soil. However, at the time, the results were interpreted as contaminants from Earth, leading to a false negative result for biological signals.
It is now understood that chlorinated organics are indeed present on Mars, but the exact mechanisms behind their formation remain unclear. Some scientists believe that the method used to heat the samples during the GCMS experiment may have inadvertently destroyed any organic materials that were present, thereby masking the presence of potential life forms.
Other experiments conducted during the Viking mission, such as the labeled release and pyrolytic release experiments, may have also contributed to the potential destruction of microbial life on Mars. These experiments involved adding liquid to Martian samples and analyzing them for signs of metabolism or photosynthesis. While these experiments did produce positive signals, they also generated conflicting results that have left scientists puzzled.
Astrobiologist Dirk Schulze-Makuch of the Technical University Berlin in Germany has proposed that the methods used during the Viking mission, and subsequent missions, may have overlooked crucial indicators of life on Mars. He believes that the experiments may have inadvertently destroyed any potential evidence of microbial life by introducing water to samples that were adapted to arid conditions.
Schulze-Makuch suggests that future missions to Mars should consider the possibility of dry-adapted life forms that utilize unconventional sources of water, such as hydrogen peroxide. He argues that instead of solely focusing on liquid water as a potential habitat for life, scientists should also investigate hydrated and hygroscopic compounds, like salts, as possible indicators of microbial life on Mars.
In light of these findings, Schulze-Makuch has called for a new mission to Mars that is specifically designed to search for signs of life using updated technology and a better understanding of Martian conditions. Nearly 50 years after the Viking mission, scientists are still grappling with the possibility that they may have inadvertently eliminated any chance of discovering life on Mars.
Moving forward, it is essential that future missions to Mars take into account the potential presence of microbial life and use more sensitive methods to detect biosignatures in Martian soil. By learning from past mistakes and adapting our approach to exploring Mars, scientists may finally uncover the long-awaited answer to the question of whether life exists beyond Earth.
