We’ve deployed so many satellites into space over the last few decades that we now have a massive orbital junk problem. The European Space Agency (ESA) noted in its Annual Space Environment Report that more than 6,600 tons of space junk are currently floating about in Low Earth Orbit (LEO), between 100 – 1,200 miles (160 – 2,000 km) above our planet’s surface.
That’s up from an estimated 6,000 tons last noted in 2023, according to NASA. It’s a mostly invisible but massive problem, because “we depend on satellites as a source of information for our daily life, from navigation, to telecommunications, to services, to Earth observation, including defense and security,” ESA Director General Josef Aschbacher told DW.
Huge numbers of little pieces
Space junk comprises of various kinds of bits and bobs. There are objects created when a payload (like an operational satellite or calibration instrument) explodes or collides with another in space. Then there are objects intentionally released during the functioning of a payload, such as covers for optical instruments or astronaut tools. Rocket bodies, or the orbital stages of launch vehicles, as well as shrouds and engines, add to the problem. And then we have pieces created from on-orbit break-up events, such as collisions, explosions, and tear and wear of spacecraft.
Even tiny pieces of space debris, as small as a millimeter wide, can do major damage to spacecraft and satellites. According to Tiago Soares, lead engineer of ESA’s Clean Space Office, “a one-centimeter piece of debris has the energy of a hand grenade.”
Now consider the fact that there are at least 1.2 million space debris objects larger than 1 cm (0.4 in) in size zooming around our orbit right now. Each of these can collide with something else, and risk creating hundreds more pieces of debris in a chain reaction, which we call the Kessler effect.
What’s more, ESA’s debris modeling software tool, MASTER, shows that in the LEO range of around 340 miles (550 km) altitude, there’s now roughly as much debris as there are active satellites.
The amount of objects, as well as their combined mass and area, have been steadily rising since the start of the space age, leading to involuntary collisions between operational payloads and space debris. The increasing space traffic, fueled by miniaturization and large constellations further contributes to the potential for generating loose debris. And in 2024, there were several major fragmentation events, as well as several smaller ones. This has led to a large increase in objects in one year, with at least over 3,000 newly tracked objects.
Keeping space clean
At present, there are no international space laws in place requiring debris to be cleaned up in LEO. However, space agencies and industry bodies including the ESA have guidelines and recommendations around mitigating the generation of debris. Those include spacecraft design considerations like:
- Preventing the release of mission-related objects (like lens caps and deployment mechanisms)
- Using materials and components that minimize fragmentation risk during and after operations
- Incorporating reliable deployment mechanisms that don’t generate debris
- Designing spacecraft structures to minimize the chance of break-up from internal energy sources
- Including end-of-life disposal capabilities in the original design
- Creating passivation systems to neutralize energy sources (batteries, propellants) at mission’s end
- Designing spacecraft that can fully burn up during atmospheric re-entry
For its part, the ESA plans to have the ClearSpace-1 debris removal spacecraft remove the suitcase-sized PROBA-1 satellite (used for tech demonstrations) from orbit in 2028. Built by Swiss firm ClearSpace, it weighs about 112 kg and can grab space junk using four ‘claws.’ Tokyo-based Astroscale also offers debris removal services. Both companies have been contracted by the UK Space Agency to remove a bunch of non-operational British satellites by next year.
ClearSpace SA
If these plans actually work out, they’ll be among the first real space junk cleanup missions ever. Scaling such efforts to clear out even a fraction of the enormous quantity of debris in LEO will be difficult, and take ages.
Hopefully, as launches continue to become cheaper and more accessible, we’ll see more garbage removal in orbit – alongside ambitious plans to use satellites for things like global internet access and beaming solar power down to Earth.
Source: ESA