News that Salmonella bacteria came back from a trip to outer space deadlier than before sparked headlines earlier this fall. It might seem like fodder for a science-fiction thriller, but such temporary changes are par for the course when bacteria encounter new environments—and researchers have seen it before without the need for a rocket ship.

“These are not mutated bugs from space,” emphasizes Cheryl Nickerson of Arizona State University, who led the team that sent the cultures onboard the space shuttle in September 2006 and reported the work in the Proceedings of the National Academy of Sciences USA. “The bacteria aren’t doing anything new.” Instead, she says, the space environment acted to “globally reprogram how the bacteria regulated the expression of their genes” and thus the levels of various proteins, enabling the bacteria to adapt to the changing conditions.