Astrobiologists plan a stratospheric hunt for microorganisms that could have seeded life beyond Earth.
The search of life in extreme environments on Earth is going to the edge of space. NASA scientists and engineers are planning to launch a balloon to the upper atmosphere to retrieve samples of microorganisms.
"This is really the last ecosystem on the planet to be explored. There's just not much known," said microbiologist David Smith, a recent University of Washington PhD graduate who will be joining NASA full-time in January.
Smith heads a project called Microorganisms in the Stratosphere, or MIST, designed to fly a balloon to the upper atmosphere to collect microorganisms. The goal of the mission is to determine the concentration of cells in the stratosphere and figure out what percentage are alive.
"There's very little doubt in my mind they're there," Smith told Discovery News. "But can we detect them? Can we build instruments to detect things that are in such low concentrations? You're pretty much at the edge of space."
If microorganisms are detected, scientists would then want to know where they came from, how long they were they airborne and if the radioactive environment caused any DNA mutations.
Earlier studies found that living organisms can reach the outer fringes of Earth's atmosphere, but how long they remain viable is unknown.
Smith believes that if microorganisms can survive the intense ultraviolet radiation in the stratosphere, they may be able to withstand transport to other bodies in the solar system.
"If there are microorganisms all over the atmosphere, they may be escaping and I think it's likely that there's Earth-life all over the solar system," Smith said. Collecting and analyzing samples from the stratosphere also would be good practice for looking for life beyond the home world, whether those organisms are terrestrial in origin or indigenous to another planet.
"Contamination is always going to be a concern with this work. It's going to be the same when we look for life on Mars. You're going to have to prove that you didn't bring microbes with you on your instruments. You have to put in layers and layers and layers of control," Smith said.
Beyond the search for extraterrestrial life, surveying microbial populations in the upper atmosphere also would help researchers understand how pathogens spread between the continents and where rain forms.
"Dust and microbes can be transported long distances around the world by atmospheric winds," University of Florida researcher Andrew Schuerger wrote in an email to Discovery News.
"Understanding how microbes can be moved in global dust plumes will give insights into the role of global dust on the movement of pathogens and non-pathogens between continents," he said.
In addition, some microbes have been shown to enhance the formation of ice crystals in clouds, which can lead to rain. A better understanding of where these microbes are located would help scientists create better computer models to predict rainfall.
MIST is targeted for launch from NASA's Wallops Flight Facility in September.
David Smith in front of the Mt. Bachelor Observatory, where atmospheric samples are collected. Andrew Schuerger, University of Florida