Russian Scientists say that they have found traces of sea plankton and other microorganisms on the surface of International Space Station، ISS.  
Baffled by the results of an experiment of taking samples from illuminators (windows) and surfaces of the Russian Segment of ISS، experts are in question on how they got there and survived، with lack of oxygen، freezing temperature. vacuum space and cosmic radiations.
Head of the Russian ISS Orbital Mission، Vladmir Solovyev said that the results of the experiment are unique.
Itar-Tass News Agency of Russia reports that such organisms can not only exist in such hostile conditions، but also، they can develop and sustain in such conditions.
They were found during cleaning and polishing of the ISS by “high precision equipment”، on the surface of ISS in the Russian Segment.
Itar-Tass further reported that، Vladmir Solvyev is not quite sure how the organisms appeared on the aircraft as they are not typical for Baikanour in Kazakhstan، from where the space station lifted off.
“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 said.
Launched in 1998  the International Space Station was intended to be a laboratory، observatory and factory in low Earth orbit. It was also planned to provide transportation، maintenance، and act as a staging base for possible future missions to the Moon، Mars and asteroids. In the 2010 United States National Space Policy، the ISS was given additional roles of serving commercial، diplomatic and educational purposes.