Retrograde

"Mankind has long dreamed of reaching out to live on other planets, and with the establishment of the Mars Endeavour colony, that dream has become reality. The fledgling colony consists of 120 scientists, astronauts, medical staff, and engineers. Buried deep underground, they're protected from the harsh radiation that sterilizes the surface of the planet. The colony is prepared for every eventuality except one--what happens when disaster strikes Earth?"--...