Exposing Microorganisms in the Stratosphere
The study transported Bacillus pumilus bacteria and their spores by helium-filled balloon to the stratosphere of Earth (~31 km above sea level) and monitored the ability of the microorganisms to survive in extreme Martian-like conditions such as low pressure, dryness, cold, and ionizing radiation.[3] If microbial metabolism, growth, or replication is achievable, independent of Earth's surface, then the search for habitable zones on other worlds should be broadened to include atmospheres.[3] Moreover, measuring the endurance of spore-forming bacteria that were previously isolated from spacecraft assembly facilities, may help predict their survival on the surface of Mars and enhance planetary protection procedures.[4] The microorganism tested was Bacillus pumilus (strain SAFR-032), a resilient radiation-tolerant spore-forming bacteria isolated from a clean room environment in a NASA spacecraft assembly.E-MIST and other science payloads attached to the balloon's gondola were returned to the surface under a parachute, where waiting researchers recovered the biological samples for analysis.