Most of the space junk floating in space consists of non-functional satellites, sent rocket stages, fragments from the disintegration and collisions of other satellites and rockets, and other mission-related debris such as lost equipment.

According to the European Space Agency the number of space debris in orbit, estimated by statistical model, result as follows: 34.000 objects greater than 10 cm; 900.000 objects from greater than 1 cm to 10 cm and more than 120 million objects from greater than 1 mm to 1 cm. And the total mass of all these objects in Earth orbit is more than 9400 tonnes.

Space junk is the result of space exploration. As long as humans launch objects into orbit with rockets, space debris is inevitable.

It is with the so-called “Space Surveillance Networks” (SSN) that all debris in space orbiting the Earth are constantly monitored. These are mechanical radars, ground telescopes and sophisticated space based optical sensors that detect, track and catalogue space debris. Then, a Space Surveillance and Tracking (SST) system also exists to detect space debris, and it is used to determine and predict the orbits of these objects.

In 2019, the European Space Agency (ESA) called for experts to submit a solution for clearing space debris from space. The Swiss start-up ClearSpace was selected and in a joint initiative with the ESA is now planning to send a satellite-size claw device in orbit to intercept a 100 kg fragment of an old European Vega rocket, called Vespa, left over from a launch in 2013. The launch of this particular "retrieval device" is scheduled for 2025 and will represent the first real clean-up mission on the planet. The ESA said that it would provide “key expertise” and funding for the mission, while ClearSpace would cover the rest of the cost through commercial investors.

The time has come to find solutions to eliminate the space junk that has been accumulating in Earth orbit for years due to our continuous space exploration. The solutions must not only consist of collecting and eliminating space junk, but also, and above all, involve techniques and technologies that make space missions themselves safer and “cleaner”.

According to the ESA (European Space Agency), there are about 7200 satellites in the space and almost 4300 are still functioning.

Space junk poses a serious problem which can intensify if nothing is done to reduce it. This is why it is necessary to prepare missions to collect the pieces which pose the major threats to new satellites. Cleaning space is no longer optional, it is a necessity and it is also our responsibility to ensure future generations can continue benefiting from space infrastructure and exploration.

The extreme ultraviolet radiation and the impact of micro-particles in space erode the surfaces of space objects, creating minuscule fragments of debris.

Our technology today is not capable of creating shields able of protecting our spacecraft (as it does in the famous Star Trek television series). However, we have managed to develop techniques that allow astronauts to protect the spacecraft they are travelling in from potential bombardment and, thus, impact, by small space debris (space junk) orbiting around the Earth at very high speeds. This is possible with a special coating vesting the outer surfaces of spacecraft called Whippie shields. These screens (shields) are mainly made of multi-layer flexible fabric, i.e. woven ceramics and also aluminium. When the striking particles collide with the spacecraft, the Whipple shields vaporize the particles into plasma and, although the plasma can spread over the surface of the space shuttle quickly, it is still too diffused to create damages to the space shuttle itself.

There are more than 28,000 objects detected and tracked in space today, and mostly we are talking about the largest debris. In the last ten years the number of satellite launches has increased ten-fold bringing the number to more than 600 per year. The rapid increase in the amount of space debris represents, without any doubt, a serious threat to the safety of all future space activities. This is why it is necessary to find solutions to eliminate space junk.

Space debris removal techniques are currently under development to reduce space junk. The European Commission is funding a program aimed at reducing space junk. It will not be possible to get rid of all the objects orbiting Earth but removing a large amount of space junk would make it safer to launch and maintain satellites and would also make missions safer than it is at present. Other initiatives are also under development and this might represent an opportunity for private investors.