Space debris: a Swiss warning to the world

In this computer-generated image, satellites and debris have been greatly enlarged to make them clearly visible. However, the immediate surroundings of the land are very crowded. Keystone

A Swiss report to stakeholders says space debris is a real danger to orbital navigation, but there are ways to reduce it. Is it enough to deter the military from making space their playground?

This content was published on Dec 15, 2021 – 10:40

November 15, 2021. At an altitude of 480 kilometers above the vast Russian steppes, the Kosmos-1408 satellite exploded in silence, amid a barrage of debris of all sizes. The machine has been retired for almost 40 years, and has just been hit by an A-235 anti-ballistic missile, launched from the Plesetsk Cosmodrome.

480 kilometers perilously close to the orbit of the International Space Station (ISS). The seven crew members are immediately required to put on their suits and take refuge in emergency capsules that allow them to return to Earth in the event of a collision.

In the Pentagon, which condemns the “unconscious and dangerous” action, Moscow replies that everything was done according to the rules of security. Especially since there are two Russian cosmonauts aboard the International Space Station – one of them is the commander.

Collisions of all kinds

This achievement is not the first. China in 2007, the United States in 2008, and then India in 2019 already participated in this kind of show of force – every time on one of its satellites.

There are also accidental collisions. On March 22, 2021, the Chinese military satellite Yunhai 1-02 hit a segment of the stage of a Russian Zenit-2 rocket, launched in the 1990s, the worst confirmed orbital collision since February 2009, when the Russian (also military) satellite hit Cosmos 2251 Iridium 33, the US communications satellite.

Each of these events, whether voluntary or involuntary, increases by a few hundred the number of debris in low orbit (up to an altitude of 2,000 km). However, there are already 34,000, counting only those that ground-based radars can detect. There are also approximately 130 million small debris, which rotate at 20 times the speed of a rifle bullet, and are also capable of causing massive damage.


Today, space agencies, private satellite launchers, and academia are fully aware of this problem. At EPFL, we’ve been working on this since at least 2012, the birthdate of Project ClearSpace, which should be the first waste-collecting satellite.

But policymakers are not yet convinced of the value of investing in waste-cleaning solutions. At EPFL, Marie Valentine Florin, Director of the Center for International Risk Management (Iran’s Revolutionary GuardsExternal link), to Muriel Richard Noka, co-founder of ClearSparce, that there is no comparative study of different solutions and the costs involved. The task of carrying out this study will be entrusted to Roman Buchs, a young physicist who has just completed his master’s thesis on space debris management. the first TransferExternal link Released in Spring 2021, completed at the end of November with options for politicians and manufacturers.

“We targeted close to 400 people in space agencies and the private sector,” the author says, acknowledging that “the Chinese and Russians are hard to reach” and that countries — the elderly are not on the list.

“Normally, continues Roman Buchs, satellites must enter the atmosphere [et donc y brûler] A maximum of 25 years after the end of its operational life. But the rule is not binding, and therefore not sufficiently enforced. About 60% of the satellites are bowing to it, while we should reach at least 90%.”

Featherweight vs. hunting animals

However, there are more and more satellites. In recent years, countries no longer have a monopoly on access to space. The direction is the constellations in low orbit. It started at the end of the twentiethe Century with Iridium and Globalstar, for satellite phone. But these devices were hardly more than a hundred.

Using OneWeb, then Starlink (SpaceX) and Kuiper (Amazon), we go to thousands of satellites, supposed to bring fast internet to the whole Earth. Their operators made sure they took all necessary precautions, either by flying low enough to automatically retract orbit after a few years, or by equipping their machines with hardware intended to make it easier to be picked up by future space locomotives.

For Roman Buchs, these small satellite clouds aren’t really the problem. Essentially, it was the states that created the problem. Instead, the new constellations are the victims. They are small satellites weighing a little more than 150 kilograms. The real problems come from the entire stages of the missiles – especially the Russian – which can weigh up to nine tons and which were launched between 1980 and 2005”, explains the expert.

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Chaos Management

However, Romain Buchs does not believe in apocalyptic scenarios, such as Kessler syndromeExternal link, which would see the nearby space so crowded that any trip there would be impossible.

“We will never be able to get the small pieces of debris, and we will focus on the larger pieces, which risk colliding and creating thousands of additional little pieces. They are about 2,000 in low orbit. It’s enough to look for three or four a year to reduce the risk dramatically,” the physicist explains .

That is the goal of Project ClearSpace, which was born in EPFL and now bears the colors of the European Space Agency (ESA).who – whichExternal link). The Japanese also have a similar project (astralExternal link). And there will be others.

As for those who claim that it is enough to stop launches into orbit, they forget how dependent our world is on satellites. Roman Buchs recalls: “To take just one example, 26 of the 55 parameters used to measure climate change can only be measured from space.”

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