Space junk is a major problem. Some of it is very large, such as burnt-out rocket stages, dead spacecraft, and a few tools lost during spacewalks. However, most of it is much smaller.
Collisions with large pieces of junk can disable or even destroy a spacecraft, as happened to the French Cerise spacecraft in 1996. Smaller debris can also cause major damage or threaten a spacewalking astronaut.
When the Hubble Space Telescope’s solar panels were brought back to Earth in 2002, they were peppered with impact craters up to 8 mm across.
Today, telescopes and radar are monitoring more than 12,000 pieces of junk down to 10 cm in size. Many millions of pieces are too small to be recorded, such as flecks of paint and dust.
Normally, these would not be a threat, but in space, debris travels at high speed. Even dust particles act like tiny bullets. ESA is tackling the debris problem in various ways. The Columbus lab on the International Space Station is protected by special shielding.
The European Space Operations Centre (ESOC) watches space debris very closely. It uses a 1 metre telescope in the Canary Islands and a radar system based in Germany. Microscopic debris is also monitored by ESA’s Proba-1 satellite and an ESA experiment on the International Space Station.