Space decontamination, an issue beyond us, but nevertheless crucial

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The increase in space traffic, particularly due to the arrival of new private players and the democratization of space technologies, results in an exponential increase of the number of objects orbiting the Terre. This situation will pose serious security problems if it is not quickly taken into account.

The main danger lies in collisions between satellites and space debris. They occur at very high speeds (between 7 and 16 km/s) and the collision of a single object can generate a multitude of additional debris, creating a domino effect and worsening the problem. This process is called the de Kessler’s syndromenamed after the American astrophysicist NASA having first alerted to this problem in 1978 (Donald J. Kessler).

Currently, we can only observe objects in orbit larger than 10 centimeters from the ground. There are approximately 35,000 objects larger than this size in orbit, of which 9,000 are active satellites with 5,200 satellites Starlink and 600 OneWeb. The number of space debris larger than 1 millimeter is estimated at around 128 million. The risk of collision is particularly high in certain areas, such as low Earth orbit, where most satellites are concentrated.

Preventative measures: deorbiting satellites

France has established itself as one of the pioneering countries in the fight against the proliferation of debris space. In fact, since 2008, the law relating to space operations laid the foundations for a proactive approach, requiring French operators to respect a certain number of rules to limit their environmental impact.

To prevent the creation of new debris, it is, for example, essential to deorbit satellites at the end of their life. This operation, complex and expensive, requires reserving part of the satellite’s energy to propel it into the Earth’s atmosphere so that it disintegrates thanks to the friction of theair.

Many satellites launched in the early years ofspace age were unfortunately not desorbed and today constitute “swords of Damocles” in orbit, increasing the risk of collisions and constituting a reserve of small, untraceable debris in the event of fragmentation.

How to capture and remove space debris?

Start-ups and companies, particularly in France, are working on the technological building blocks to get closer to this debris, to synchronize their trajectory with that of the space vehicle coming to pick them up, to catch them and finally to deorbit them. The operation is complex and expensive.

Today there are some projects to«active debris removal» (ADR, “active debris removal”) in progress. We can cite the project ClearSpace-1 of the’European Space Agency (ESA) which aims to deorbit in 2026 a piece of the 112 kilo stage of the Vega launcher.

The company Japanese Astroscale has also been developing ADR activities since 2013, with a number of in-orbit demonstrations already carried out. Her Adras-J mission, launched on February 18, 2024, aims to get closer to a third stage of Japanese H-2A launchers put into orbit in 2009 and to synchronize with this stage to validate the final rapprochement phase. Astroscale has recently set up an office in France to develop part of its activities in France. The French start-up Dark also focuses on debris interception with innovative solutions.

The activity is growing, but needs a commercial anchor in order to really “take off”. Today, only States finance this theme. It is therefore not yet profitable from an economic point of view to collect debris. To resolve this dilemma, we would need to be able to give value to debris by valuing their recycling and their reuse.

We could also try to estimate the economic cost of a collision and the large quantity of debris generated which will disrupt space operations. This shortfall triggered by inaction must be compared to the cost of the intervention of cleaning. But it is very difficult today to estimate and construct these economic models.

To remedy this problem, the idea of ​​a breakdown service, towing and repair of satellites in orbit, capable of capturing space debris, is considered. This system would be based around multifunctional spacecraft. In addition to repairing broken satellites, these craft would capture debris at the end of their repair missions, returning it to Earth’s atmosphere to disintegrate. This economic model has the advantage of generating income, thanks to the repair service and the potential valorization of materials recovered from debris.

Create an economic model that builds on current regulations

Regulation can help this economic model. The strict rule requiring that all objects put into orbit must be de-orbited at the end of their life with a probability of 100% effectively requires “systems” to be available to pick up broken down space vehicles. The analogy with breakdown packages on highways Is not far.

It would then become cheaper to pay a breakdown service to come and recover a broken down vehicle rather than having the recovery capacity yourself. This can promote a economy virtuous which cleans objects recently put into orbit, but also recovers objects from historic missions and which bother us today.

Necessary international cooperation

However, challenges remain. Development technological capturing and deorbiting space debris is still underway. In addition, an international legal framework is necessary to define the responsibilities and obligations of the actors involved.

In order to face this global challenge, France calls for concerted international action. Collaboration between nations is essential to develop effective technological and legal solutions and guarantee the security ofspace for future generations.

In conclusion, the establishment of an economic model for space depollution is a crucial issue to guarantee the security and sustainability of thespace exploration. Although there are challenges ahead, international collaboration and technological innovation can help overcome them and ensure a sustainable future for space.

Pierre Yesterday is an expert in space debris and responsible for the Tech 4 Space Care initiative at National Center for Space Studies (CNES).