Earth may need to protect itself against its own satellites in orbit.

The 7th European Conference on Space Debris, being held by the European Space Agency (ESA) in Germany, is discussing what to do about the 750,000 objects larger than 1cm are orbiting Earth at average speeds of 40,000km/h.

These are mostly made up of satellites for telecommunications.

But thousands of pieces of debris are also in orbit due to collisions and explosions between them.

The ESA say impacts between these objects delivers roughly the energy equivalent to the explosion of a hand grenade.

It says consequences for operational satellites could be "severe".

The geostationary ring is one of the most congested regions in space - this is the only orbit in which satellites move synchronously with Earth. The average distance between two objects here is only 190km | Image: ESA/ID&Sense/ONiRiXEL

About 18,000 of these pieces of debris are large enough to be regularly monitored to avoid collisions.

The ESA say the majority of these objects are the result of more than 250 explosions.

The agency say: "With the increase in the number of objects in space, experts believe that collisions among these objects, some of which have already occurred, might become the primary source for new fragments in orbit.

"Experts have proposed countermeasures that would mitigate this problem. However, significant challenges are faced by spacefaring organisations to implement these measures."

The ESA Conference on Space Debris is the largest gathering in the world on the topic hearing from leading scientists, engineers, managers, space operators, industry, academia and policy-makers from all major space-faring nations.

Talks will address issues like the current practice in implementing debris avoidance measures, the removal of debris and the deployment of several thousand satellites for telecommunications.