Here is the Wikipedia article on these little guys. Tardigrade. They are one of the most resilient lifeforms on the face of this planet. "Tardigrades are able to survive in extreme environments that would kill almost any other animal. Some can survive temperatures of close to absolute zero (−273 °C (−459 °F)), temperatures as high as 151 °C (304 °F), 1,000 times more radiation than other animals, and almost a decade without water. In September 2007, tardigrades were taken into low Earth orbit on the FOTON-M3 mission and for 10 days were exposed to the vacuum of space. After they were returned to Earth, it was discovered that many of them survived and laid eggs that hatched normally."