A clean room is an enclosed area where contaminants and pollutants are closely monitored and regulated. It’s where rockets go to be decontaminated before heading into space and space samples are stored so that the results of any later experiment or analysis are not compromised by the presence of terrestrial microbes.
NASA's Johnson Space Center (JSC) in Houston, Texas, has a NASA clean room with an ISO class 6 rating (class 1 is the cleanest and class 9 is the dirtiest) used to store Antarctic meteorites that came to Earth from other planets. It is currently under preparation to receive samples from Mars and the Bennu asteroid.
But it turns out this particular clean room isn’t so clean after all. Swabs from the floor and workbench reveal that JSC has been contaminated by a sneaky fungal infestation. The news was presented at the 49th Lunar and Planetary Science Conference held in Texas last week.
The researchers found between four and 28 cells in areas no bigger than a passport photo (51 by 51 millimeters or 2 by 2 inches). The figure was even higher inside a nitrogen-pumping air filter that had not been opened for almost 40 years. Fortunately, this was only on the outer parts of the filter so it is unlikely it infected any of the meteorites, which are stored in nitrogen-filled cabinets and protected by several more defenses.
Aside from the outside of the air filter, the level of terrestrial microbes at the center is on par with those in other clean rooms, including the NASA Jet Propulsion Laboratory in Pasadena, California, and the Kennedy Space Center in Florida. However, the bulk of the microbes in these other centers were bacteria.
In JSC, between 83 and 97 percent of the microbes at the meteorite lab were fungi, specifically from the genus Penicillium. This is problematic because fungi could easily infect the samples and adjust the chemical makeup of the meteorites, potentially skewing any experiments or analysis that later takes place.
So, why are there high rates of fungi here compared to other locations? It may be that previous tests haven't used the correct combination of food and incubation conditions to examine the swabs for fungi.
“I wonder if we’ve not found fungi in other locations because we weren’t looking for them,” said Aaron Regberg, who presented the findings.
“I’d characterize [the results] as eye-opening,” Marc Fries, who curates the cosmic dust collection at JSC and wasn't involved in the research, told Science Magazine. “It drives home this point that fungi are an important part of microbial contamination.”
[H/T: Science Magazine]