2409 new objects were launched into space in 2022, that’s more than ever before.
Last year though, also saw a record number of satellites reenter Earth’s atmosphere.
The rising number of reentries is not necessarily a bad thing. Disposing of satellites efficiently is one of the most important things for keeping low-Earth orbits safe.
However, most objects reenter in an uncontrolled manner: they are switched off at the end of their mission and left to fall and burn up in Earth’s atmosphere.
There is good news though. Advancing technology has seen a recent increase in “controlled reentries” for rocket bodies. A controlled reentry allows operators to remove their hardware from protected regions more quickly and with greater control over where, when and how it reenters – and even lands – at the cost of allocating some fuel to do so.
By the way, just because an older satellite wasn’t designed to be controlled during its descent doesn’t mean it’s impossible to do so. In July 2023, our teams guided the Aeolus satellite to burn up over uninhabited regions in the Atlantic and Antarctica, even though the satellite was designed in the late 1990s with no intention to control it in this way.
Our planet is surrounded by spacecraft helping us study our changing climate, save lives following disasters, deliver global communication and navigation services and help us answer important scientific questions.
But these satellites are at risk. Accidental collisions between objects in space can produce huge clouds of fast-moving debris that can spread and damage additional satellites with cascading effect.
In this animation, find out how teams at ESA’s European Space Operations Centre in Darmstadt, Germany, take action to keep satellites safe after receiving an alert warning of a possible collision between an active satellite and a piece of space debris.
When the alert is raised, ESA experts determine the risk of a collision and plan a collision avoidance manoeuvre that can be used to get the satellite out of harm’s way if necessary.
Additional observations of the piece of space debris help the team better understand its path and the risk of collision. If that risk remains too high (typically 1 in 10 000), the planned manoeuvre is carried out to temporarily change the orbit of the satellite until the threat has passed.
Each manoeuvre comes at a price. They take skill and time to plan, cost precious fuel – shortening the lifetime of the mission – and often require instruments to be temporarily shut off, preventing them from collecting important data.
While most alerts do not end up requiring evasive action, the number of alerts is rapidly increasing. Hundreds are already issued every week. Several companies have begun to launch large constellations into low-Earth orbit to provide global internet access. They have great benefits, but could be a source of huge disruption if we do not change our behaviour.
In just a few years, our current methods for avoiding collisions in space will no longer be enough. To safeguard humankind’s continued access to space for future generations, ESA is developing technologies for an automated collision avoidance system.
We are Europe’s gateway to space. Our mission is to shape the development of Europe’s space capability and ensure that investment in space continues to deliver benefits to the citizens of Europe and the world. Check out https://www.esa.int/ to get up to speed on everything space related.
