If an extraterrestrial civilization were to observe our civilization from afar, the most striking feature would probably be our ability to destroy our environment. Atmospheric pollution, a plastic continent, climate change, deforestation, mass extinctions of species... in the face of all this sad record, the degradation of the space surrounding our planet might seem anecdotal.

However, space has become indispensable for a considerable number of tools that we use without even thinking about it and whose degradation could have serious, even dramatic consequences. We should not wait for the day when an airliner crashes because a few centimetres of metal has destroyed a positioning satellite to realize that there is a real problem.

A team of British scientists has just sounded the alarm, saying that international regulation and investment are urgently needed to prevent space from being damaged as much as the oceans by human activity. 

"Space is becoming more and more accessible, and every country, university, company or even school is now able to build a satellite and launch it into space, and that's really exciting," says Sir Martin Sweeting, a professor at the University of Surrey. "Space tourism will initially be for the super-rich, but it will become increasingly affordable over time, just as air travel was in the last century," he continues. "But we have to proceed carefully, we don't want to create more debris, because the debris we already have is a big risk for future robotic or manned missions."

These are pieces of satellites or rockets that are wandering over our heads. They're the result of collisions or ejections of unnecessary parts during launches, such as first-stage parts. There are also satellites that are out of service. All this has accumulated over 60 years of space conquest to astronomical levels.

It is difficult to have precise figures on the number of these pieces of metal and plastic. NASA alone would follow in the 23,000 objects larger than 2 cm, but this is only the tip of the iceberg. Last year, at its 7th conference on the subject, the European Space Agency (ESA) estimated the total weight of spacecraft in orbit around the Earth at 8,000 tonnes, including the... 6,300 tonnes of decommissioned satellites and more or less large pieces!

According to some estimates, there are about 750,000 pieces larger than 1 cm and 166 million pieces larger than 1 mm. When we know that a piece of metal barely 5 mm thick can make a 40 cm bump in a solar panel, we can imagine the danger to space navigation of these clouds of debris moving at an average speed of 40,000 km/h.

The situation could become much worse with the multiplication of mini-satellites, the CubeSat. Researchers at the University of Southampton (England) have modelled the evolution of space traffic by adding these CubeSats, which tend to be sent in whole squadrons. According to their results, these new arrivals could increase the risk of catastrophic collisions (destruction of a satellite...) by 50%.

Under the impact of violent speed-related shocks, these objects of all sizes subdivide into smaller and smaller objects, thus increasing the risk of collision.

Indeed, in space everything goes very fast! The danger comes from the fact that an object, even a tiny one, launched at very high speed can do a lot of damage. A speck of dust thrown at several tens of thousands of kilometres per hour at the window of a manned flight can make a hole in it, causing an air leak and all the disastrous consequences one can imagine.

Even if this pollution is much less serious and urgent than the many others that can unfortunately be found on Earth, the symbolism is nevertheless cruel: even in space, man has succeeded in the feat of polluting his environment.