A round-trip journey to Mars would probably kill a crew of astronauts, unless they had some futuristic defense against radiation from the sun and from galactic cosmic rays. Would microbes be hardy enough to survive? We may soon find out.

The Planetary Society, a nonprofit based in Pasadena, Calif., has packed a handful of miniature space travelers—bacteria, yeast, even tiny invertebrate animals—into a capsule on the Russian Phobos–Grunt spacecraft, expected to launch as soon as November 8. The experiment, called Phobos LIFE, for Living Interplanetary Flight Experiment, is designed to test the hypothesis that early life could have hopped from one planet to another on board meteoroids.

Phobos–Grunt will not only take microbes to Phobos and back, but will also scoop up soil samples and return them to Earth—an ambitious feat never before accomplished on another planet's moon. (Read more about the mission here.) If all goes according to plan, the round-trip will take three years.

Click here for a slide show of five Phobos LIFE passengers.