Space debris

Space Debris

Space debris, also called space junk or cosmic debris, are old human-made things floating in space near Earth. These include broken satellites, pieces from old rockets, and tiny bits made when things crash or break apart. Even very small pieces, like paint flakes, can be dangerous because they move very fast.

These pieces of space debris can damage satellites, space stations, and other spacecraft. For example, the International Space Station has special shields to protect it from tiny bits flying by. Sometimes, bigger pieces are so risky that the space station has to move to avoid a crash.

There are many of these pieces floating around. As of April 2025, there were over 40,000 objects big enough for people on Earth to track. But there are also millions of smaller pieces that we can’t track, and they can still hurt satellites and other spacecraft. Scientists and space agencies are trying to find ways to track these pieces and maybe clean some of them up, because space debris is a big problem for anything that travels into space.

History

Space debris began to build up in Earth's orbit when the first artificial satellite, Sputnik 1, was launched in October 1957. Before that, natural pieces from Earth may have already been in space. After Sputnik, groups like the North American Aerospace Defense Command (NORAD) started tracking objects in space, such as satellites and parts of rockets.

Over time, more pieces of debris appeared because of explosions in space, sometimes from old rocket parts breaking apart. As technology improved, scientists could track these pieces better. Today, many pieces of space debris remain in orbit, and people are working to understand and manage this growing problem.

Characterization

As of January 2019, there were over 128 million tiny pieces of space debris smaller than a centimeter. There were also about 900,000 pieces between 1 and 10 centimeters in size, and around 34,000 larger pieces.

Low Earth Orbit (LEO), the area of space closest to Earth, holds most of the space debris—about 85%. Many satellites orbit here and pass each other often. This can lead to collisions. When two satellites collide, they create even more debris, which can make it risky for other satellites. Scientists worry that too many collisions could make some parts of LEO too dangerous for satellites to use.