The researchers sandwiched dry layers of three kinds of biological test ingredients, including bacterial endospores, endolithic cyanobacteria, and epilithic lichens, into rocks analogous to rocks from Mars. They then simulated the shock pressures Martian meteorites experienced when they were ejected from Mars and determined the ability of the organisms to survive the harsh conditions.
But not, like, the conditions of centuries to millenia in space. Which is also kind of important to the scenario.
STARGAZING: All I see are the lights of a billion places I'll never go. --Howard Tayler, Schlock Mercenary