Bacteria common to spacecraft sent from the Earth may be able to survive the harsh environs of Mars, long enough to contaminate it with terrestrial life, research says.
The search for life on Mars remains a stated goal of National Aeronautic and Space Administration's (NASA) Mars Exploration Programme and Astrobiology Institutes.
To preserve the pristine environments, the bioloads on spacecraft headed to Mars are subject to sterilisation, designed to prevent the contamination of the Martian surface.
Despite these efforts, recent studies show that diverse microbial communities remain at the time of launch.
The sterile nature of spacecraft assembly facilities ensures that only the most resilient species survive, including acinetobacter, bacillus, escherichia, staphylococcus and streptococcus.
Researchers from the University of Central Florida (UCF) replicated Mars-like conditions by inducing desiccation, low temperatures, and UV irradiation.
During the week-long study they found that E. 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 dust or UV-protected niches in spacecraft, a UCF release said.
"If long-term microbial survival is possible on Mars, past and future explorations of Mars may provide the microbial inoculum for seeding Mars with terrestrial life," the researchers said.
"Thus, a diversity of microbial species should be studied to characterise their potential for long-term survival on Mars," they added.
The findings were published in Applied and Environmental Microbiology, published by the American Society for Microbiology.