Solovyev was quoted as saying by Itar-Tass: "The results of the so-called 'Test' experiment are unique. On the surface of the [ISS] windows we found traces of marine plankton - the microparticles - that will become the subject of further studies." While the experiments on the matter were finalized last year, it is still unclear how the microparticles could get all the way to the ISS, Solovyev said.
"[Plankton in] such phases of development is found on the surface of the ocean. It isn't characteristic to Baikonur," he explained, referring to Baikonur Cosmodrome in Kazakhstan from where crew and cargo deliveries to ISS are launched.
"It turns out that there are some rising air currents, which settle on the surface of the station" Solovyev added. The former cosmonaut, who spent nearly a year in orbit back in the 1980s, said that outer surface of ISS is "heavily contaminated" by the waste products from engines of the arriving spacecraft, atmospheric discharges from the station during spacewalks by the crew and other factors. We are currently conducting special operations to be able to somehow to polish and clean up the windows [at the ISS]. This is especially important during long space flights," Solovyev concluded.