A magnified image of the berry-shaped Tersicoccus pheonicis, a new species of bacteria discovered in NASA's clean rooms. NASA/JPL-Caltech Nasa does not need to travel to the stars to find new forms of life – it has discovered a new species of bacteria living in the special rooms used to build spacecraft.

The US space agency uses sterilised clean rooms to build spacecraft for missions to other planets to help avoid any contamination that may hinder the search for life.

These rooms are kept extremely dry, are cleaned with chemicals including bleach and have negative air pressure to keep out any contaminants.

Ultraviolet light and heat treatments are also used to kill off any life on objects that go in and workers are required to wear special suits.

However, Nasa has revealed that it has discovered a hardy new species of microbe that has is able to survive in this highly inhospitable environment.

The berry-shaped bacteria, called Tersicoccus phoenicis, is so unusual that it has been classified not just as a new species but also a new genus.

Scientists said they have now found the bacteria in two separate clean rooms – one in Florida where Nasa's Mars Phoenix Lander was constructed and at the European Space Agency's facility in Kourou, French Guiana.

"This particular bug survives with almost no nutrients," said Parag Vaishampayan, a microbiologist at Nasa's Jet Propulsion Laboratory in California.

"We want to have a better understanding of these bugs, because the capabilities that adapt them for surviving in clean rooms might also let them survive on a spacecraft.

"The same bug might be in the soil outside the clean room but we wouldn't necessarily identify it there because it would be hidden by the overwhelming numbers of other bugs."

Analysis of the new bacterium, which is about one micrometre across (0.00004 inches) is published in the International Journal of Systematic and Evolutionary Microbiology .

The name for the bacteria comes from Tersi, the Latin for clean, and coccus, which is Greek for berry.

Phoenicis is derived from the Phoenix Mars Lander, the spacecraft that was being constructed when the bacterium was first collected in floor swabs.

Nasa regularly conducts swabs and tests of its clean room facilities to monitor for the presence of bacteria.

It means that if a spacecraft does detect signs of life during a mission, it can be checked against the species known to inhabit clean rooms.

This allows scientists to determine whether they have found extraterrestrial life or a species from Earth that has hitched a ride.

Only species that are able to survive in harsh, nutrient poor conditions are generally found in clean rooms.

"Tersicoccus phoenicis might be found in some natural environment with extremely low nutrient levels, such as a cave or desert," said Dr Vaishampayan.