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This portal provides basic knowledge on astronomy and highlights current research projects and collaborations in Switzerland.

Image: ESO

Space debris

A computer-generated image of objects orbiting the Earth whose location is being tracked today. About 95% of these objects are space debris. The dots are scaled to the image size and not to the size of the Earth depicted. Their depiction is therefore too large when compared to the Earth.
A computer-generated image of objects orbiting the Earth whose location is being tracked today. About 95% of these objects are space debris. The dots are scaled to the image size and not to the size of the Earth depicted. Their depiction is therefore too large when compared to the Earth.Image: NASA
A computer-generated image of objects orbiting the Earth whose location is being tracked today. About 95% of these objects are space debris. The dots are scaled to the image size and not to the size of the Earth depicted. Their depiction is therefore too large when compared to the Earth.
A computer-generated image of objects orbiting the Earth whose location is being tracked today. About 95% of these objects are space debris. The dots are scaled to the image size and not to the size of the Earth depicted. Their depiction is therefore too large when compared to the Earth.Image: NASA

We humans have launched many rockets and satellites into space in recent decades. By no means all of this material has returned to Earth, burnt up or is still travelling through space in a safe and controlled manner. Tens of thousands of pieces of space debris are orbiting the Earth unused and uncontrolled, endangering active satellites, space stations and astronauts travelling in space. The most spectacular incident so far was a collision of two satellites. Iridium 33, an active telecommunications satellite, collided with the decommissioned satellite Kosmos 2251 on 10 February 2009. The impact speed was more than 40,000 km/h. The satellites shattered into more than 2000 pieces.

Satellites and launch vehicles

Space debris consists mainly of satellites and rocket stages that are no longer in use. Some parts that are no longer needed still contain fuel and explode. Others collide. Both have the same effect: the number of scrap particles is increasing. Military tests also create debris. Some states have weapons with which they can destroy objects in space - so-called anti-satellite weapons.

Objects are recorded and monitored

The most comprehensive catalogue of artificial objects in space is the US Space Surveillance Network Catalogue. All parts, functional and non-functional, that are relevant for space activities are registered here. However, not all data is accessible, as it also includes information on military satellites. The ESA is also working on compiling a catalogue of this nature.

Switzerland cleans up in space

Simulations show that if we do not actively retrieve parts from space, the number of collisions will increase. This will even happen if we ensure that no new space debris is created. This is because, as described above, the existing debris can explode or collide, multiplying the number of uncontrolled parts. Several projects exist which illustrate how space debris can be removed from orbits. The aim is always to slow down the debris so that it loses altitude and burns up in the atmosphere. Switzerland is very active in this area. It helps to localise the parts precisely by, for example, taking measurements at the University of Bern's Zimmerwald Observatory. And Switzerland also helps with the removal of existing waste. One ESA project with Swiss participation is RemoveDebris. This consists of a small satellite equipped with a harpoon and net that hunts for space debris. The Swiss Centre for Electronics and Microtechnology (CSEM) was an important partner in this project.
ClearSpace, an EPFL start-up, is leading the ClearSpace-1 project of the ESA Clean Space initiative. They are developing a device that will capture the rubbish with gripper arms and bring it into a lower orbit.

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