Chinese scientists report that they’ve found a novel bacteria on the Tiangong space station, but can’t confirm if it evolved on the station itself or on Earth before hitching a ride skyward. Similarly, a separate study shows that NASA’s clean room—used for the Phoenix Mars lander mission—also contained 26 novel bacteria species. The first case concerns China’s Tiangong space station. Around 20 percent the size of the International Space Station (ISS), Tiangong similarly conducts experiments in fields ranging from physics to biotechnology and beyond—at last count, the station has enabled some 180 scientific investigations. In Tiangong’s case, scientists can’t be sure if this novel bacteria evolved while on the space station, or if it came to be on Earth and simply hitched a ride via rocket.