In 1976, the two NASA Viking landers reached a halt on Mars.
Their life detection experimental findings continue echoing throughout the scientific community — sparking an ongoing debate about a crucial question: Does life exist on Mars?
Today, a fresh study revisits and reassesses the outcomes of the Viking Biology experiments.
Perchlorate finding
The most notable alteration following those 1970s experiments was the identification of elevated amounts of perchlorate on Mars Perchlorates along with non-biological oxidizers account for the findings of the Viking missions, thus eliminating the necessity to assume the presence of life on Mars.
The recently published paper observes that “the finding of perchlorate on Mars by the Phoenix mission offers an explanation for the outcomes recorded by the Viking Lander missions. The thermal breakdown of perchlorates within the instruments' ovens could account for the absence of organic compounds detected. Additionally, the buildup of hypochlorite in Martian soil may also play a role.” cosmic ray The decomposition of perchlorate could account for the observed reactivity when nutrient solutions were introduced into the soil during the Viking Biology Experiments.
The document also notes, "a non-biological interpretation of the Viking findings does not rule out the presence of life on Mars."
Revisit the results
The recently published paper titled "Revisiting the Viking Biology Experiments on Mars" has been written by prominent Mars researchers. Christopher McKay Richard Quinn and Carol Stoker, both from the science division of NASA's Ames Research Center located near San Francisco at Moffett Field, California, along with a third author, have collaborated on this work.
The potential for upcoming Mars sample returns and future missions, possibly incorporating life-detection tools, prompts us to reconsider the outcomes of the Viking biology experiments," propose the researchers. "Although much has evolved since Viking touched down on Mars, certain aspects remain constant. One such unchanging factor over the last half-century is our comprehension of how life operates under frigid and arid conditions.
In communications with Christopher McKay, he mentioned It should be emphasized that our findings from the Viking mission do not indicate conclusively either the absence of life on Mars nor confirm its presence.
McKay stated that their main argument revolves around the idea that the Viking mission detected perchlorates and other oxidizing agents on Mars, "which were responsible for the responses observed in the Viking biological tests."
This implies that the outcomes from the Viking Biology experiments cannot be employed to support a strategy for ensuring astronauts' health and safety, nor to establish policies regarding the quarantine of samples and/or astronauts upon their return to Earth, under the assumption that there is no life on Mars.
New data
In their article published in the scientific journal *Icarus*, the three researchers highlight significant alterations due to missions sent to Mars. They state, "Undoubtedly, the most crucial novel information comes from the unexpected findings made by the Phoenix Mission They point out that Martian soil contains approximately 0.5% perchlorate. This extremely high level of perchlorate remains poorly understood; however, it has significant implications for the findings from the Viking missions.
In their publication, the researchers state that the findings regarding the perchlorate model and the subsequent inference that Viking failed to detect life in Martian surface soils will play a role in discussions about future missions involving sample returns or human expeditions to Mars.
The Outer Treaty bans 'harmful alterations to Earth’s environment due to the addition of extraterrestrial substances,' " McKay and his team point out. They also emphasize that additional experiments are crucial for gaining deeper insights into the chemistry of Martian soil and the potential existence of life on Mars.
Good targets
To summarize their research paper, they conclude that the perchlorate model for the Viking results "fails to confirm the absence of life." life on Mars , nor does it suggest that the ongoing quest for signs of life on Mars, whether in the past or present, is futile."
Certainly, as proposed by the research team, they firmly advocate for seeking evidence of current life in upcoming missions. Ideal locations include salt deposits and polar surface ice.
This latest study has been published in Icarus .
