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.