Life has a remarkable way of emerging in unexpected places, often testing the patience of scientists who strive to keep certain environments unchanged for research purposes. This is precisely what happened with samples taken from the asteroid Ryugu a few years ago.
Contamination of samples. An analysis of a rock sample from Ryugu recently revealed the presence of microorganisms of terrestrial origin. Despite the rigorous precautions taken to prevent biological contamination, some microorganisms managed to infiltrate the sample.
The findings of the study were published in Meteoritics & Planetary Science.
Sample A0180. The contaminated sample was designated with the code A0180. It’s part of the dust and rock samples collected in 2018 by the Hayabusa2 probe, which is operated by the Japan Aerospace Exploration Agency.
Hayabusa2 was the first mission to successfully return samples from an asteroid and the first to bring extraterrestrial material back to Earth, excluding lunar missions.
The panspermia hypothesis. Preventing biological contamination is crucial during asteroid sample-return missions. This meticulous approach is essential for investigating the potential presence of life or remnants that might indicate its existence. The search for evidence of life in the asteroids of our solar system is vital to exploring the panspermia hypothesis.
Panspermia suggests that life or key compounds necessary for its development, like amino acids, could survive the rigors of space travel while “riding” on asteroids. This implies that life could originate on one planet in the solar system and transfer to another through a series of asteroid impacts.
Life broke through. Scientists won’t likely find clues about the origin of life in our solar system in sample A0180. The recent sample analysis revealed that, despite efforts to prevent contamination, it had been infected by microbial life from Earth.
During their study, researchers discovered rods and filaments of organic matter, possibly “filamentous microorganisms” similar to those found on Earth. Studying these microorganisms’ population changes led the team to estimate that these prokaryotic organisms have a generation time of 5.2 days.
Preparing the sample. Population statistics indicated that biological contamination likely occurred during the preparation of the sample. Given the resemblance between the microorganisms found in the sample and known terrestrial organisms, scientists rule out the possibility that they were already present on the asteroid when the sample was collected.
From Ryugu to Bennu and beyond. The recent findings are concerning, not only because this particular sample was contaminated but also because they highlight the inadequacies in our planetary protection efforts. These efforts aim to prevent Earth microorganisms from spreading throughout the solar system via spacecraft and vice versa.
If everything goes according to plan, space agencies in the U.S., Europe, and China might bring back Martian soil samples in less than a decade. This would represent a significant milestone in space exploration and the search for signs of extraterrestrial life. It’ll be crucial for its study to ensure that terrestrial microorganisms don’t contaminate these samples.
Moreover, maintaining other important space samples in pristine condition will be essential for maximizing the information scientists can extract from them. This is the case for the asteroid Bennu sample collected by NASA’s Osiris-REx, the largest of its kind.
Image | JAXA et al.
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