If we do find life on Mars, it would be good to know it isn’t something that stowed away on the trip from Earth.

That’s the goal of an ongoing study of microorganisms on spacecraft—including some that have been found to be surprisingly tolerant of extreme dryness, cold, and massive doses of radiation. “Could these organisms potentially survive on Mars?” asked Susan Childers, microbiologist and a research scientist in biology at Colby. “There are still a lot of unknowns.”

Those unknowns didn’t stop the journal Nature from writing about the research last month. Childers, whose expertise is the study of microbial life in extreme environments, is part of a team of scientists working to identify microorganisms that have survived NASA’s attempts at “bio-burden reduction,” the process of trying to make spacecraft if not sterile, then closer to it. The team—including researchers at the University of Idaho—is analyzing strains of organisms collected from the Mars rover Curiosity before its launch in 2012.

The project is ongoing and scientists don’t know if the organisms could survive the trip to Mars or could survive on the Red Planet if they make it there. They do know that some of the strains of bacteria are tougher than anyone expected. “You expect them to die after you expose them to a thousand joules of radiation,” Childers said. “Some of our guys are living after exposure to a thousand, even two thousand joules. We don’t know how or why, but hopefully later on we can address the question of what makes them that much more tolerant.”

Childers and other team members, including microbiologist Stephanie Smith at the University of Idaho, have been given access to microorganisms collected not only from Curiosity, the Mars rover, but from the Viking landers—probes sent to Mars in the 1970s. The researchers are identifying the strains of microorganisms and then subjecting them to a battery of tests, “so that, should they survive the flight, we’ll know who to look for.”

The project is in the third year of a three-year NASA-funded grant, and more funding is being sought. Childers said that if the next phase of the study is funded some of the work would take place at Colby, where samples of two of the strains from Curiosity are now stored.

Some tests are aimed at exploring the range of possible outcomes if a spore, which is a type of survival mode entered into by some microorganisms under stress, were to land on the surface, she said. “Would it, could it come out of that and potentially grow? Is it possible?” Childers asked. “Or maybe it would land in one of those briny pockets that, from what I understand, can seasonally flourish there. Then hunker down and wait until the next season?”

That, she said, with a scientist’s characteristic understatement, “would be pretty interesting.”—Gerry Boyle ’78