Researchers from the US and India working with the US Space Agency have discovered four types of bacteria on the ISS, three of which are completely unknown.

Cyns Ellert said three "unknown" bacteria were found between 2015 and 2016, the first on a board inside the ISS, the second in the dome, and the third on the dining table.

He added: "The fourth bacteria were known, found within an ancient filter returned to Earth in 2011."

All four strains belong to the soil and freshwater bacteria family and help stabilize nitrogen and plant growth.

The researchers said that the fourth bacteria is previously known and is called "Methylorubrum rhodesianum," explaining that the remaining bacteria species are "unspecified" and do not belong to the known species.

They were named: IF7SW-B2T وIIF1SW-B5 وIIF4SW-B5.

The team, led by University of Southern California geneticist Swati Belani, proposed the new species "Methylobacterium ajmalii," named after the most beautiful Khan, a renowned Indian biodiversity scientist.

Some might wonder how these bacteria got into space?

The simple answer is that astronauts living at the space station have been growing small amounts of food for years. So, it's not surprising that we find "beneficial" microbes inside the soil.