0 unwanted objects or material left in space by human activity, such as pieces of old or destroyed equipment:
The space station Mir became the largest piece of space junk ever to fall to Earth.
The computers' tasks include tracking satellites and space junk.
The objective, scientists say, is to gain insight into the effects of orbiting space junk on satellites.
Agencies that fly satellites must follow rules to dispose of them in ways that minimize space junk.
