Space debris: Swiss alert to the world


In this computer-generated image, the satellites and debris have been greatly enlarged to make them clearly visible. However: Earth’s immediate surroundings are very crowded. Angular stone

Space debris is a real risk to orbital navigation, but there are ways to reduce it, says a Swiss report to affected parties. Will it be enough to dissuade the military from making space their playground?

This content was posted on December 15, 2021 – 10:40 am

November 15, 2021. 480 kilometers above the immense Russian steppe, the satellite Kosmos-1408 silently explodes, in a bundle of debris of all sizes. Retired nearly 40 years ago, the machine has just been hit by an A-235 anti-ballistic missile, fired from the Plesetsk cosmodrome.

480 kilometers is dangerously close to the orbit of the International Space Station (ISS). The seven crew members are immediately asked to don their suits and take refuge in the emergency pods that would allow them to return to Earth in the event of a collision.

At the Pentagon, which denounces an “unconscious and dangerous” act, Moscow responds that everything was done in compliance with safety rules. Especially since there are two Russian cosmonauts aboard the ISS – one of whom is the commander.

Collisions of all kinds

This weapons feat is not the first time. China in 2007, the United States in 2008 and India in 2019 had already engaged in this kind of show of force – each time on one of their own satellites.

There are also accidental collisions. On March 22, 2021, the Chinese weather satellite Yunhai 1-02 hit a piece of a Russian Zenit-2 rocket, launched in the 1990s. It was then the worst confirmed orbital collision since February 2009, when the Russian satellite (also military) Kosmos-2251 hit Iridium 33, an American communications satellite.

Each of these events, intentional or not, causes the number of debris in low orbit (up to 2,000 km altitude) to increase by a few hundred. However, there are already 34,000, counting only those that ground-based radars are able to detect. There are also around 130 million small pieces of debris, which spin 20 times the speed of a rifle bullet and are also capable of doing massive damage.

Alarm

Today, space agencies, private satellite launchers and academies are very aware of the problem. At the Escola Politécnica Federal de Lausanne (EPFL), we have been dealing with this since at least 2012, the birth date of the ClearSpace project, which is supposed to be the first garbage collector satellite.

But decision makers are still not fully convinced of the usefulness of investing in waste cleaning solutions. At EPFL, Marie-Valentine Florin, Director of the International Risk Governance Center (IRGCexternal link), points out to Muriel Richard-Noca, co-founder of ClearSparce, that there is no comparative study of the different solutions and the costs they entail. The task of carrying out this study will be entrusted to Romain Buchs, a young physicist who has just completed his master’s thesis on space debris management. a first reportexternal link will be released in spring 2021, complemented in late November by options for politicians and industrialists.

“We targeted about 400 people from space agencies and the private sector,” the author explains, while admitting that it is “difficult to reach the Chinese and Russians” and that the general staff are not on the list.

“Usually, continues Romain 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 comply, while we must reach at least 90%”.

Featherweight vs. giants

However, there are more and more satellites. For several years, states no longer have a monopoly on access to space. The trend is towards constellations in low orbit. Started at the end of 20and century with Iridium and Globalstar, for the satellite phone. But these machines were no more than a hundred.

With OneWeb, then Starlink (SpaceX) and Kuiper (Amazon), we moved on to thousands of satellites, supposedly to bring fast internet to the whole Earth. Its operators have ensured that they take all necessary precautions, whether flying low enough that deorbit occurs automatically after a few years, or equipping their machines with devices intended to facilitate their capture by future space tugs.

For Romain Buchs, these clouds of small satellites are therefore not really the problem. “Basically, it was the states that created the problem. The new constellations are rather the victims. They are small satellites, which weigh just over 150 kilos. The real problems come before entire stages of rockets – especially Russian ones – that can weigh up to nine tons and that were launched between 1980 and 2005”, specifies the expert.

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dealing with chaos

However, Romain Buchs does not believe in apocalyptic scenarios such as Kessler Syndromeexternal linkthat would see nearby space so confused that any flight would become impossible.

“We will never be able to collect the small debris, we will focus on the larger ones, which are at risk of colliding and creating thousands of additional small pieces. They are about 2000 in low orbit. It would be enough to get three or four a year to considerably reduce the risk”, explains the physicist.

This is the objective of the ClearSpace project, born at the EPFL and which now bears the colors of the European Space Agency (ESAexternal link). The Japanese also have a similar project (Astroscaleexternal link). And there will be others.

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

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