The team grew bacterial colonies in dishes and then turned down the heat, the pressure and the oxygen. Hyperbaric chambers reduced atmospheric pressure down to just 7 millibar, with many strains perishing as the conditions worsened. (Earth atmospheric pressure is about 1,000 mbar.) S. liquefaciens was able to survive at 7 mbar, freezing temperatures, low oxygen and increased carbon dioxide--just like the conditions on Mars. Interestingly, two known extremophile species did not make it.