The only thing I got out of it is that lichen can survive in space for a certain amount of time. Anything beyond that is just speculation.
On one of the space pings, someone figured out that our Voyager spacecraft, launched in the ‘70’s, would take just short of 100K years to reach Alpha Centari, the closest star outside of our solar system at present speed had they been aimed for an intercept course.
I find it hard to believe anything would survive the time, vacuum, cold and radiation for anything approaching that amount of time.