Unidentified Bacterial Strain Discovered Inside China’s Space Station

In October 2022, China launched the final module of its orbiting space station. Since then, it hasn’t just been astronauts aboard Tiangong—an unusual and previously unknown microbe has also been occupying low Earth orbit.

A group of scientists examined swabs collected from inside the Tiangong space station, revealing a form of bacteria not known to inhabit Earth. The discovery, published in the International Journal of Systematic and Evolutionary Microbiology, highlights the need to study the newly identified microbial strain to protect the health of the astronauts on board the Chinese space station.

The previously unknown microbe, named Niallia tiangongensis after the space station where it was discovered, has proven especially resilient, surviving in the harsh conditions of microgravity. Tiangong’s Shenzhou-15 astronauts swabbed a cabin on the space station in May 2023 as part of a survey by the China Space Station Habitation Area Microbiome Program. Follow-up studies of the swabs traced the newly discovered microbe to a strain that appears similar to Niallia circulans—a rod-shaped, spore-forming bacterium originally isolated from soil.
It’s not clear whether the strain evolved on the space station or had already evolved on Earth before hitching a ride to low Earth orbit.

The newly described species can break down gelatin for nitrogen and carbon, helping it endure harsh conditions by forming a protective biofilm. It also packs its essential chemistry into tough spores, allowing it to survive in extreme environments.

Last year, scientists uncovered a mutated strain of drug-resistant bacteria thriving under the harsh conditions of space aboard the International Space Station (ISS).
Although Niallia tiangongensis and its ISS counterpart are both space-faring strains, they differ in composition and function, according to the paper.

It’s not clear if the bacterium poses a threat to the Tiangong astronauts, but the scientists behind the discovery say further examination of the new strain needs to be carried out. “Understanding the characteristics of microbes during long-term space missions is essential for safeguarding the health of astronauts and maintaining the functionality of spacecraft,” the paper reads.