Earthly microorganisms hitching a ride on spacecraft may be first to colonize Mars and other celestial bodies, scientists say.
Some microbes are able to survive the journey in the vacuum of space, which is fraught with temperature extremes and radiation, and they could become the first life on the Red Planet.
Furthermore, these microbes could make it difficult for human explorers to determine whether microbial life we find on other celestial bodies is actually native or something that we brought there ourselves, according to Space.com.
Spacecraft are already regulated so that only a certain level of microbial life – called the “bioburden” – can be transported on it. But three studies of the bioburden published in 2012 in the journal Astrobiology suggest that the threshold isn’t set high enough and too many microbes are being sent off into space.
Two of the studies also found that the spore-forming bacterium Bacillus pumilus SAFR-032, which has a high tolerance for ultraviolet (UV) radiation and the peroxide used to clean spacecraft, could survive in Mars-like conditions.
Researchers exposed the hardy bacterium to a simulated Martian atmosphere by using the European Technology Exposure Facility (EuTEF) mounted to the International Space Station.
Bacillus pumilus SAFR-032 survived for 18 months. Spaceflight experts told Space.com that a mission to Mars would take half that time.
The third study found that some rock-colonizing cellular organisms are also capable of surviving 18 months on the EuTEF.
Discovery of life on the moon, Mars or any other astronomical object could very well be a rediscovery.