Of the 15,900 or so orbital objects classified as space junk, about 6.300 objects were left over by Russia, it says.
All in all, a total of 17,000 manmade objects were orbiting the Earth on October 31, 2014, experts of the institute's ballistic center say. Only 1,300 objects in that number are active-duty space probes.
The rest of objects - carrier rockets, non-operating satellites and debris of various other vehicles - belong to the category of space junk.
“Among the active-duty probes, the US grouping consisting of 427 items is the biggest,” the report says. “Russia has 129 probes and China has 123.”
The US has left over 4,570 objects in orbit and China has left about 3,660 objects.