Since the world's first artificial satellite was launched into orbit in 1957, thousands of fragments of space debris of unused satellites and rockets have risked collision for satellites and spacecraft in Earth orbit.
In addition to meteorites, there are also human-made debris in orbit. These include unused satellites and spacecraft as well as launching platforms.
The collision of two satellites results in a large amount of space junk. Also, some countries such as the US, China and India could use missiles to destroy their own satellites, which causes thousands of fragments to spread into orbit.
Currently, orbiting space debris poses no major risk to exploration attempts but is seen as a major threat to other orbiting satellites.
Every year, all satellites, including those of the International Space Station (ISS), have to move out of the way of all incoming space junk to avoid hundreds of collisions.
The ISS has maneuvered to avoid space debris 25 times since 1999.
In 1957, the Soviet Union launched the first artificial satellite, Sputnik-1, into Earth's orbit.
Since 1957, more than 6,050 rockets have been launched. It has caused 56,450 trackable space objects in orbit.
About 28,160 of those objects remain in orbit and are tracked by the US Space Surveillance Network. Around 4,000 of them serve as active satellites.
More than 560 in-orbit fragmentation events have been recorded since 1961. Only seven of them were associated with collisions.
