Scientists aboard the International Space Station (ISS) have been left stunned to discover extra-terrestrial life in outer space.

They are stumped as to how to they got there but claim studies support the ability of the extra-terrestrials to exist in zero gravity, extreme temperatures, while being belted by cosmic radiation and despite a lack of oxygen.

The team of Russian experts stumbled across the startling find during a routine cleaning and polishing mission of the outside surface of the ISS.

“Results of the experiment are absolutely unique.” said the chief of the Russian ISS orbital mission Vladimir Solovyev, according to a report by Itar-Tass news agency.

View photos An astronaut on a space walk outside the International Space Station. NASA / Getty Images More

"We have found traces of sea plankton and microscopic particles on the illuminator surface.”

Using "high-precision equipment”, the team apparently made the discovery during a routine cleaning operation.

"This is particularly needed during long space flights," Solovyev said.

View photos The International Space Station orbits Earth. ESA/NASA/Getty Images More

"Plankton in these stages of development could be found on the surface of the oceans.”

"This is not typical for Baikonur. It means that there are some uplifting air currents which reach the station and settle on its surface," he was quoted as saying.

Morning news break – August 20