Microbes Can Outlast Space Itself, and That Changes Everything
How Long Can Life Wait?
How long can an organism stay inert and still come back to life? Experiments on the International Space Station show that Deinococcus radiodurans shielded from ultraviolet light can survive years of direct exposure to interplanetary space, and perhaps decades. That endurance shapes how we build probes to avoid contaminating Mars, lends support to lithopanspermia — the idea that life may have traveled from Mars to Earth inside rocks — and raises the tantalizing possibility of reviving microbes dormant for hundreds of millions of years.
They imply that live microbes from Earth have already reached Mars and are vegetating under the carapaces of landers.