The quest to find answers to space's junk problem

Distribution of space debris around the Earth. Source: ESA.

Thirty-four thousand. This the number of objects that are larger than 10cm currently in orbit around the Earth. According to the European Space Agency (ESA), there are about 130 million objects that measure between 1 mm to 1 cm in space today, and 900'000 objects between 1 cm to 10 cm in size. The situation is alarming, as the number of active satellites and the consequent risk of collisions have increased exponentially in the last decade.

The environmental, legal and technical issues related to space debris management have become an international focus point,  and one that the International Film Festival and Forum on Human Rights (FIFDH) chose to discuss in an online debate last week. Experts and space engineers addressed the threat that failed satellites, rocket bodies or fragments represent for the practicability of the space environment.

In December, a Swiss start-up was selected to lead the world’s first mission to clean up space.  ESA signed a contract with the EPFL spin-off ClearSpace, with the mission slated to launch in  2025, as part of its Active Debris Removal/ In-Orbit Servicing (ADRIOS) programme. The company has been tasked with deorbiting a hefty piece of a Vega rocket left in orbit since 2013 - a  technical achievement that could transform the entire space industry.

Why this is important. Access to space and sustainability of space operations are strategic components of our societies, as our dependence on global internet access and telecommunications grows. An exponential increase in the number of satellites launched over the past decade has endangered the environment as the risk for collisions becomes more important. The latest ESA space environment report shows the increase of objects in space.

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Evolution of the space environment in terms of number of objects. Source: ESA.

“All satellites are destined to become debris, except those that come back,” said Christophe Bonnal, space debris expert at the CNES Launcher Directorate. “Each year there are more objects being launched than there are objects being deorbited. In 2020 only, a thousand objects were left in orbit.”

There is less debris being launched today than during the Cold War, as most satellites are active, Bonnal continues. If the regulations are applied correctly, when the time comes, the same satellites should be deorbited.

However, collisions do happen often, about ten every year, thus generating new debris and new risks. Even the smallest fragments have visible consequences as can be seen in the before and after picture of satellite Sentinel-1A’s solar array. Here, a millimeter fragment left a damaged area with a diameter of about 40 cm.


Some other collisions have far greater consequences. In 2009, for example, the Russian military satellite Kosmos 2251, which had been inactive for years, collided with the American communications satellite, Iridium33. As a result, both satellites were completely destroyed.

About 2’000 fragments have been orbiting the Earth ever since.

The notion of responsibility. A series of agreements and conventions have been drawn up over the years in an attempt to regulate space activities  including the UN 1967 Outer Space Treaty and the 1972 Convention on Space Liability.

“The launching state, whether the state owns the satellite, the infrastructures destined for the launch or serves as a launching territory, is responsible for the objects in space. There is no distinction between an operational satellite or a debris. Responsibility is the same,” said Benjamin Guyot, in charge of launch services contracts for the European Space Agency (ESA).

This means that the launching state remains responsible for the consequences of potential future collisions in space but also on the Earth, if these objects were to come back with destructive material results.

The notion of responsibility is also affected by the shift between governmental to commercial use of space. In the fifties and the sixties, the governments were the main customers of space assets. The Cold War was raging and countries were eager to spy on each other, Bonnal explains. In the eighties and nineties, commercial space applications, such as TV, geostationary or telecom satellites, started to develop.

Today, commercial applications and operators are competing in space and have become equally responsible actors in the process. The technologies have miniaturised and decreased in price significantly, and so has the cost of a launch.

In-orbit servicing. ClearSpace will lead a consortium of European companies building a spacecraft with four robotic arms, which in 2025 will capture   and take down the upper part of a Vespa (Vega Secondary Payload Adapter) and prove that cleaning up space is feasible.

Once the 100-kilogram object is captured, it will be brought down to the Earth's atmosphere to be decomposed. The high velocity at which it enters the atmosphere will trigger the consumption.

More than a technical achievement, the Swiss mission is a first step towards the development of major servicing activity in space, Bonnal adds. The aim is to set up a form of tow truck service that would help address the extreme traffic around the Earth and help to deal with the debris. The question remains on who would pay for this new service.

“There are no rules today,” says Guyot.“If the polluter-pays principles were to be imposed today, the missions would become highly expensive and refrain access to space to even more countries.”

This first mission will cost about €100m, says ClearSpace co-founder and CEO, Luc Piguet. The costs are high at this stage, but an important percentage of the investment is destined to non-recurring engineering costs. The idea is to reduce these costs in order to make the in-orbit service affordable to states and operators, through the technological developments and the operational modes.

The future. The ESA, The United Nations Office for Outer Space Affairs, states and private actors are bringing sustainability, space traffic management and coordination to the table. The problem is that competition is high and no one wants to take the first step, Guyot concludes.

“It is only when the space environment will become so polluted and so dangerous that states will start acting. It is also a ratio between the cost of the mission and the cost of deorbiting the objects. It will have to be done because we will not have a choice.”

International Geneva could possibly play its part with the United Nations and the International Telecommunication Union (ITU). And the neutrality of Switzerland is definitely a non negligible aspect in the sensitive negotiation process.

Looking ahead, technology is key. Destroying debris is not the only way forward. Companies are already examining the possibilities to reuse the space elements, although we are not there yet. It will probably be another twenty or thirty years until then, according to ClearSpace.