- Could Earth bacteria survive on Mars?
- Spacecraft need to be sterilised
Bacteria commonly found on spacecraft may be able to survive the harsh environs of Mars long enough to inadvertently contaminate the Red Planet with terrestrial life, according to research published in the journal Applied and Environmental Microbiology.
The search for life on Mars remains a stated goal of NASA’s Mars Exploration Program and Astrobiology Institutes. To try and prevent the Martian surface from being contaminated by Earth microbes, spacecraft are subjected to sterilisation procedures.
But despite the efforts made to reduce the “bioload” on spacecraft, recent studies have shown that diverse microbial contaminations remain at the time of launch. And the sterile nature of spacecraft assembly facilities ensures that only the most resilient species survive, including acinetobacter, bacillus, escherichia, staphylococcus and streptococcus.
To see how well Earth microbes might survive on Mars, researchers from the University of Central Florida replicated Mars-like conditions in the laboratory — extreme dryness, low air pressure, low temperatures and UV irradiation.
During the weeklong study they found that Escherichia coli bacteria, a potential spacecraft contaminant, might likely survive but not grow on the surface of Mars … if it were shielded from solar UV irradiation by thin layers of dust or in UV-protected niches in spacecraft.
The researchers say that if long-term microbial survival is possible on Mars, then past and future spacecraft explorations could provide the microbial “seed” for contaminating Mars with terrestrial life. They conclude that “a diversity of microbial species should be studied to characterise their potential for long term survival on Mars”.
Adapted from information issued by American Society For Microbiology / NASA.