Curiosity, NASA’s exploration vehicle that went to Mars in 2012
Advances in DNA technology make it possible to sequence virtually all the genes of these microbes and compare their genetic profiles with much more comprehensive databases.
An international team of researchers has identified 26 previously unknown bacterial species in NASA’s “clean rooms,” the name given to spaces designed to be some of the most sterile environments on the planet, used to assemble spacecraft and probes destined for other worlds.
The discovery, described in a May article in Microbiome, shows that even under extreme conditions of cleanliness, nutrient shortages and strict control of air and humidity, some microorganisms can persist for long periods.
Cleanrooms are a centerpiece of the so-called “planetary protection”: the set of measures designed to prevent terrestrial microbes from contaminating other celestial bodies, which could compromise life-search missions and alter extraterrestrial ecosystems.
“It was a moment to ‘stop and recheck everything’”, said the Brazilian Alexandre Rosadoco-author of the study and professor of Biosciences at King Abdullah University of Science and Technology (Saudi Arabia), speaking to . According to him, despite being rare, these bacteria were found in different clean room environments and demonstrated the ability to persist.
The microorganisms were detected in facilities at the Kennedy Space Center in Florida, where NASA assembled the Phoenix Mars Lander in 2007. During that period, a team led by Kasthuri Venkateswaran, senior scientist at the Jet Propulsion Laboratory, collected and preserved 215 bacterial strains from the floor of one of the assembly areas. The samples were obtained before the spacecraft arrived, during the assembly and testing process and, later, after moving to the launch pad.
At the time, available tools limited the rigorous, large-scale identification of new species. But 17 years later, advances in DNA technology have made it possible to sequence virtually all of these microbes’ genes and compare their genetic profiles with much more comprehensive databases, including surveys carried out in clean rooms in subsequent years. This approach made it possible to assess not only “who” is present, but also how often and for how long certain microorganisms reappear.
Genetic analysis revealed a set of survival strategies compatible with highly hostile environments. Among the adaptations found are genes associated with resistance to cleaning chemicals, the formation of biofilms, the repair of DNA damaged by radiation and the production of resistant dormant forms, such as spores. These characteristics can allow survival in microscopic fissures and “dead zones” that are less accessible to disinfection.
Now, if some microbes manage to escape routine controls in a clean room, there is the possibility — although not yet demonstrated — that organisms with similar adaptations can withstand part of the conditions of space travel and reach other worlds. But Rosado emphasizes that real survival will depend on factors not tested in the study, such as vacuum, intense radiation, extreme cold and high levels of ultraviolet radiation on the surface of Mars.
To address this uncertainty, the team is finalizing the construction of a “planetary simulation chamber” in Saudi Arabia, designed to expose these bacteria to conditions similar to those in space and on Mars, including low pressure rich in carbon dioxide, high radiation and large temperature swings. The first pilot tests are scheduled for the beginning of 2026.
