What if stars turned out to be space debris ? Today, millions of pieces of debris of different sizes orbit the Earth.
To avoid this potential scenario and solve the space debris problem, several innovative solutions exist.
What is space debris ?
For more than 60 years, humans launched satellites that have helped them understand what is happening around our planet. However, these satellites are also responsible for space debris, non-functional artificial orbital objects, which can have several origins.
Indeed, they can result from satellite malfunctions (such as end-of-life or breakdowns), the aging of protective coatings, or anti-satellite tests that cause explosions and fragment dispersion.
They can also result from rocket stages, the highest of which are left adrift in space or, more rarely, from the loss by astronauts of equipment such as a glove, a camera or a screwdriver. On January 2, 2025, even a Tesla car was discovered in orbit. It was launched into space in February 2018 by Space X, the company created by Elon Musk, aboard its Falcon Heavy rocket. Today, it is less than 240,000 km from Earth, even closer than the moon.
In space, debris can collide and the resulting impacts generate even more fragments, further expanding the cloud of space debris.
According to the CNES (Centre National d’Etudes Spatiales), the number of space debris larger than 1 mm is around 128 million. 1 Of these 900,000 are larger than 1 cm and around 34,000 are larger than 10 cm.2
The consequences of these debris on planet Earth
Today, space debris does not affect us directly. However, if nothing is done to counter this space pollution, in the future, humans will no longer be able to launch satellites. The reason : too much debris in space and therefore little room for human innovation. With an end to the signals necessary for telecommunications, Earth observation or even ongoing missions, life on earth would leap into the past.
This scenario, illustrated in the film Gravity, and not excluded by NASA, is called the “Kessler Syndrome”. This concept, introduced by American astrophysicist Donald Kessler, states : « the more debris there is in orbit, the more they will collide with objects or other debris, causing a chain reaction that will increase the number of debris exponentially. ».3
This is what happened on March 22, 2021. A Chinese military satellite (Yunhai 1-02) was violently hit by debris from an old Russian rocket from the 1990s (Zenit-2), causing an explosion.
Beyond the damage caused to active satellites, it cannot be ruled out that debris will make a comeback among us. Although re-entry heat destroys the majority of space debris before it reaches Earth, the fall of large space debris is a possible consequence. This happened at the end of 2024, in Kenya. A metal object approximately 2.5 m in diameter and weighing approximately 500 kg crashed onto farmland. The damage could have been considerable if it fell on a populated area.
Possible solutions
Experts meet every year to try to correct human error.
According to Luisa Innocenti, head of the Clean Space program at ESA (European Space Agency), « we have to stop polluting and then we have to pick up the waste, in other words the debris ».4
Several strategies can help limit space pollution, some of which, due to the lack of funding, are only at the project stage :
- Attach an outer casing « Whipple Shields » to the satellites, to protect them from possible collision.
- Create new generation satellites which would leave their orbit at the end of their life and self-destruct upon atmospheric re-entry.
- Passivate satellites at the end of their life, to discharge their batteries and avoid their explosions.
- Divert debris using a laser that puts pressure on space debris to reduce its speed and move it away from its orbit, so it can burn up in the atmosphere.
- Implement debris recovery techniques (robotic arm, space fishing net, space tugs, …)
For more information :
1- https://cnes.fr/dossiers/debris-spatiaux
2- https://cnes.fr/actualites/debris-spatiaux-un-risque-loupe
3-https://www.radiofrance.fr/franceculture/le-syndrome-de-kessler-pieges-sur-terre-2871600
