After collecting the microbe samples from inside the International Space Station, Whitson transferred them from petri dishes to test tubes within the Microgravity Science Glovebox. This is the first time such a task has been performed in space.

NASA

“Once we actually got the data on the ground, we were able to turn it around and start analyzing it,” said Aaron Burton, NASA biochemist and the project’s co-investigator. “You get all these squiggle plots and you have to turn that into As, Gs, Cs, and Ts.”

These four letters — representing Adenine, Guanine, Cytosine, and Thymine, respectively — are the only four bases that make up every strand of DNA for every living organism that we know of. By analyzing how these bases are arranged within a DNA strand, scientists are able to identify which organism the DNA came from.

“Right away, we saw one microorganism pop up, and then a second one, and they were things that we find all the time on the space station,” said NASA microbiologist Sarah Wallace.