“Asteroid Ryugu Sample Contaminated by Earthly Microorganisms: The title is ”What It Means for Space Science’
A groundbreaking attempt to study pristine asteroid material has taken an unexpected turn: Terrestrial bacteria can be found in a sample from the asteroid Ryugu. This isn’t evidence of alien life, but it’s also a reminder of why it’s so difficult to ensure Earth contaminants don’t get in—even with the most extreme precautions.
**Asteroid Ryugu: **A window in the early Solar System
Japan’s Hayabusa2 mission, launched in December 2014, collected 5.4 grams of rock, pebbles, and dust from Ryugu – a carbonaceous asteroid about 200 million miles from Earth. These asteroids are believed to be primordial building blocks of the solar system, and studying them is like looking into … well … its origins. While fiery descents scar meteorites through Earth’s atmosphere and subsequent surface contamination, Ryugu samples were collected in space, making them much less likely to have been impacted by the same processes.
The specially designed capsule containing the samples was delivered to Earth in 2020. After making a soft landing at Australia’s Woomera Range Complex, the capsule was quickly relocated to an ultra-clean facility in Sagamihara, Japan. It had been in vacuum-sealed chambers and nitrogen-filled environments. Everyone took every precaution to keep the sample pure.
Contamination Discovery
But despite these extraordinary measures, Imperial College London researchers made a worrying discovery. In their sample of Ryugu, they identified organic rods and filaments that looked like microorganisms. Once they had exhaustively analyzed the samples, they confirmed that these microorganisms were, in fact, terrestrially derived and that the asteroid sample had become so while in space. The findings, published in Meteoritics and Planetary Science, underscore a troubling reality: Not even the best contamination controls will do.
Valid Reasons Why I Collected Pristine Samples
Asteroid samples like Ryugu are invaluable for understanding how Earth’s solar system evolved and where life on Earth came from. Previous analyses of Ryugu have detected organic molecules, furthering a theory that asteroid and meteorite impacts brought life’s building blocks to Earth. However, contamination can muddy these findings and make identifying terrestrial from extraterrestrial materials more difficult.
Of course, this isn’t the first high-profile asteroid sample return mission. In 2020, the OSIRIS-REx spacecraft grabbed material from asteroid Bennu; the samples will land on Earth by 2023. Ryugu’s discovery of organic matter does not mean Bennu’s also contaminated, but it suggests sample protection protocols aren’t perfect, and other missions may have trouble with the same issue.
This is a wake-up call for future space missions.
It’s a wake-up call to the scientific community that contamination of the Ryugu sample is a problem. In order for space agencies such as JAXA and NASA to further refine their techniques when acquiring pristine material, it must remain uncontaminated. However, as scientists continue to expand our scope of space exploration, being able to preserve the integrity of extraterrestrial samples will become so important for furthering our knowledge of the universe.
Looking Ahead
However, this setback will not negate the significant achievement of the Ryugu mission in helping researchers gain insight into the composition and history of these asteroids. Future missions, including possible Mars sample returns and lunar exploration efforts, will benefit from continued research into the sample and what was learned from the contamination.
Despite the tantalising prospect of unravelling some of the cosmos’s biggest secrets, asteroid missions have proved to be as difficult as they are exciting, as this discovery shows.
