A newly published study reveals that a bacterium discovered by NASA, known as Tersicoccus phoenicis, has the ability to enter a dormant state, leading scientists to consider the possibility that it may have inadvertently been sent to Mars. This microbe was first identified in 2007 in two NASA clean rooms, which are specifically designed to prevent contamination during spacecraft assembly, located over 4,000 kilometers apart.
Research published in the journal Environmental Microbiology explains that T. phoenicis can effectively “play dead” by entering a hibernation-like state when deprived of nutrients. Madhan Tirumalai, the lead author of the study and a microbiologist at the University of Houston, confirmed this finding, stating, “It is not dead. It was playing dead. It is only dormant.”
Survival in Extreme Conditions
The unique characteristics of T. phoenicis raise significant questions regarding its survival capabilities. NASA employs rigorous sterilization protocols in clean rooms, which include heating, chemical treatments, and radiation to eliminate microbial life. Despite these efforts, T. phoenicis not only survived but also evaded detection during subsequent sterilization checks.
In 2013, NASA announced the discovery of this bacterium, clarifying that it posed no health risks. However, the recent study aimed to delve deeper into its survival strategies. By depriving T. phoenicis of nutrients and placing it on sterile Petri dishes, researchers observed that it entered a dormant state within 48 hours. This dormancy lasted for seven days, even after attempts to revive it by reintroducing nutrients. The researchers later found that exposure to a specific protein could reactivate the bacteria’s biological functions.
Nils Averesch, a microbiologist at the University of Florida who was not involved in the study, noted, “The fact that this bacterium can intentionally suspend its metabolism makes survival on spacecraft surfaces or during deep-space cruise more plausible than previously assumed.”
Implications for Mars Exploration
The clean room where T. phoenicis was first identified was part of the preparations for the Phoenix Mars Lander, which successfully reached Mars. This raises concerns about the potential for Earth microbes contaminating other planets. While the idea is alarming, experts like Averesch suggest that the likelihood of T. phoenicis surviving on Mars is minimal. He stated, “Anything directly exposed on the Martian surface is unlikely to survive.”
There is also the possibility that T. phoenicis has evolved specifically to thrive in the sterile environments of spacecraft clean rooms, as it has not been found in other natural settings.
The findings from this study could also enhance cleaning protocols for NASA’s clean rooms. By understanding how to coax dormant bacteria back to activity, scientists may develop more effective strategies for ensuring that spacecraft remain free from contamination.
This research highlights the remarkable survival mechanisms of microscopic life forms, emphasizing that even the tiniest organisms possess extraordinary resilience. As exploration of other planets continues, understanding these microorganisms becomes crucial in preventing contamination and maintaining the integrity of scientific discoveries.
