What is space junk?

Space junk is also referred to as space debris, which includes all man-made objects in space that are no longer useful or have been discarded. These can be anything from defunct satellites, abandoned spacecraft, rocket stages, and fragments from past space missions.

The debris can range in size from large objects like old satellites, rocket bodies, and discarded launch vehicle stages, to small debris like paint flakes, screws, and bolts. These smaller objects are particularly dangerous as they travel at extremely high speeds and can cause significant damage to operational satellites or even manned spacecraft.

The accumulation of space junk in orbit poses a significant threat to future space missions and activities. As the number of satellites and space missions increases, so does the risk of collisions, which can create more debris and exacerbate the problem.



Moreover, the increasing amount of space debris can also pose a threat to life on Earth. If a large object falls back to Earth, it could cause significant damage to property or even injure or kill people.

Space agencies and private companies are working on developing methods to mitigate the problem of space junk, such as de-orbiting satellites at the end of their lives, using reusable rockets, and active debris removal technologies.

How much space junk is there?

How does space junk occur?

The entirety of space junk results from the launch of objects from Earth, and it remains in orbit until it re-enters the atmosphere.

Objects in lower orbits, typically a few hundred kilometers from Earth, have shorter lifetimes in space and can return to Earth within a few years. During re-entry, most of the debris or satellites burn up, preventing them from reaching the ground. However, objects or satellites placed in higher altitudes of 36,000 kilometers, like communication and weather satellites in geostationary orbits, can remain in orbit for hundreds or even thousands of years.

Space debris can also result from collisions or anti-satellite tests conducted in orbit. In the rare event of a satellite collision, it can break apart into thousands of new pieces, creating additional debris. Some countries, such as the USA, China, and India, have conducted missile tests aimed at destroying their satellites, which ultimately creates thousands of new pieces of hazardous debris.

How can we clean up space junk?

The United Nations has called for all companies to remove their satellites from orbit within 25 years after completing their mission. However, enforcing this request can be difficult since satellites can and often do fail. To address this challenge, numerous companies worldwide have proposed innovative solutions.

Some of these solutions involve the removal of dead satellites from orbit by dragging them back into the atmosphere, causing them to burn up. This can be accomplished in various ways, such as using a harpoon to capture the satellite, catching it in a large net, employing magnets to retrieve it, or even firing lasers to increase the satellite's atmospheric drag, leading to its eventual descent from orbit.

These techniques are solely applicable for larger satellites in Earth's orbit, and they are not suitable for picking up smaller pieces of debris like metal and paint flecks. In such cases, there is currently no feasible way to collect these objects, and we must rely on their natural re-entry into Earth's atmosphere.