It’s called “forward contamination” in terms of inadvertently sending Earth bacteria to other worlds.
Indeed, fouling the nest of say Mars – perhaps a niche for microbial life – is a concern of NASA researchers.
New research published in the April issue of the journal Applied and Environmental Microbiology reports that bacteria common to spacecraft may be able to survive the harsh environs of Mars long enough to accidentally contaminate Mars with terrestrial life.
To preserve the pristine environments, the “bioloads” on spacecraft headed to Mars are subject to sterilization designed to prevent the contamination of the Martian surface.
Despite sterilization efforts made to reduce the bioload on spacecraft, recent studies have shown that diverse microbial communities remain at the time of launch.
While the sterile nature of spacecraft assembly facilities ensures that only the most resilient species survive, some do, including acinetobacter, bacillus, escherichia, staphylococcus and even streptococcus – a bacteria that causes strep throat.
Seeding Mars
Researchers from the University of Central Florida have replicated Mars-like conditions, including heavy doses of ultraviolet (UV) that reach the surface due to the red planet’s thin atmosphere.
During the week-long study they found that Escherichia coli, a potential spacecraft contaminant, may likely survive but not grow on the surface of Mars if it were shielded from UV irradiation by thin layers of martian dust or UV-protected niches in spacecraft.
“If long-term microbial survival is possible on Mars, then past and future explorations of Mars may provide the microbial inoculum for seeding Mars with terrestrial life,” say the researchers in the recent paper. “Thus, a diversity of microbial species should be studied to characterize their potential for long term survival on Mars.”
The Applied and Environmental Microbiology is a journal published by the American Society for Microbiology.
By Leonard David