In an effort to keep outer space clean and junk-free, Russia and its partners plan to sink the International Space Station (ISS) in the ocean after its scheduled retirement in 2020, Russian Space Agency Roscosmos said in a statement on Wednesday.

"After it completes its existence, we will be forced to sink the ISS. It cannot be left in orbit, it's too complex, too heavy an object, it can leave behind lots of rubbish," said deputy head of Roskosmos space agency Vitaly Davydov.

The ISS was placed in Earth’s lower orbit in 1998 and is a joint project of space agencies from the United States, Russia, Europe, Japan and Canada.

Space junk can be disastrous for spacecrafts and satellites, according to astronauts. Mir space station was also sunk by Russia into the Pacific Ocean in 2001 when its 15-year life cycle ended.

Russia strives to lead in space exploration after NASA’s 30-year space shuttle mission ended on July 21 with successful landing of the final space shuttle, Atlantis.

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The International Space Station is pictured against the Earth in this image taken from NASA TV May 23, 2010. REUTERS/NASA TV