ESA Press Release
In brief
Spacecraft orbit our planet, carrying out important work to study and provide global communication and navigation services. They also help us answer important scientific questions.
But their orbits are churning at deadly fragments of past Fast-moving fragments of rockets and satellites that are no longer in use trapped in orbit that threaten our future in space.
In 2002, the Inter-Agency Debris Coordination Committee (IADC) published the Space Debris Mitigation Guidelines. These guidelines outline how to design, fly and dispose of space missions so that there is no further debris. These guidelines were a major step towards protecting our orbits and have been the basis for space policy, national legislation, and technical standards for over two decades.
ESA’s Space Debris Office published an annual report in 2016 Space Environment Report to provide a transparent overview of global space activities and determine how well these and other international debris-reduction measures are improving the long-term sustainability of spaceflight.
These are some of the key findings from the 2022 report.
In-depth
- Today, more satellites are launched than ever before.
- This is due to the growing number and scale commercial satellite constellations in low Earth orbit.
- Most rocket bodies today are placed in safe disposal orbits, but not all, before they can become dangerous debris clouds.
- However, active satellites have to avoid objects that were launched decades back and have been broken into pieces.
- At the end of their lives, not enough satellites are removed to low-Earth orbits that are congested.
- Technological advances have made it possible to track and spot smaller fragments of space debris.
- While our space behavior is improving, it is still not sustainable over the long-term.
We’ve spotted more than 30 000 pieces of space debris
Space debris continues to grow.
Space surveillance networks regularly track more than 30,000 pieces space debris. We are seeing more unidentified objects (UI) as our technology improves. Because of the time that has passed between their creation, and our observation, it is difficult for us to trace their origins back to a specific place. fragmentation event.
Based on ESA models the true Number of objects greater than 1 cm in diameter is likely over one million.
Smaller satellites; larger constellations
The 2020s marked the dawn of a new era for spaceflight.
The technology required to create large satellite constellations has become more reliable and compact. In the last two decades, there has been an increase in the number of satellite constellations. Exceptional increase in the number of commercial satellites launched to near-Earth space, with the vast majority being smaller satellites weighing between 100 – 1000 kg.
Many of these constellations were launched to provide communications services around the world. These constellations have many benefits, but they will be a challenge for long-term sustainability.
More satellites are sharing a ride
Constellations are also changing how satellites enter space. 2021 saw record numbers of rocket rockets carrying multiple satellites into space simultaneously. This reduces satellite launch costs, but can make it more difficult for surveillance networks and to keep track of individual objects.
Low-Earth orbits are becoming increasingly crowded
The increase in launch traffic and the long-lasting nature of space debris in low-Earth orbit is causing a significant number of close encounters, known as “conjunctions”, between active satellites and other objects in heavily congested orbits.
This plot shows how many times a typical satellite at different altitudes was alerted to a collision during 2021.
Satellites are more likely to encounter constellations and satellites at lower altitudes. Satellites at higher altitudes encounter debris objects that are left over from a limited number of important fragmentation events.
Not all alerts need evasive action. Spacecraft operators will find it increasingly difficult to respond to all alerts manually as they increase in number. ESA is working with other technologies to develop automated systems that use artificial intelligence. collision avoidance manoeuvresReduce false alarms.
In some areas, we are making progress
One positive note for the debris environment is that many rocket bodies launched today to deliver satellites into low-Earth orbit are disposed of sustainably. Some are burned using a Controlled reentry into Earths atmosphere, while others are placed in orbits that naturally decay within 25 years.
Rocket bodies are the largest objects that we send into space. Their removal from busy orbital highways decreases the likelihood of them exploding or fracturing into dangerous debris.
There is still work to do on satellites that are nearing the end of their missions in low-Earth orbit. While a growing number of disposal attempts succeed, too many satellites remain in orbits that are critical to their removal.
To limit the growth of space debris, we must have a minimum of 90% success rate in removing all types of space objects before we can begin cleaning it up.
But we must do more
Although we are more responsible for what we launch today than we were yesterday, our current efforts are not sufficient.
If we don’t make significant changes in the way we launch, fly, and dispose of space objects then an extrapolation from our current behavior into the future will show how the number of fatal in-space collisions could increase.
Kessler syndrome could develop over the long term. This is when the density of orbit objects is high enough that collisions create a cascade effect. Each crash generates debris that increases the probability of more collisions. Certain low-Earth orbits could become inhospitable at this point.
It is time to act
This situation can be avoided if more space actors follow IADCs space debris reduction guidelines. prevent in-orbit explosionsAvoid in-orbit collisions. Spacecraft should be safely disposed of at the end of their mission.
It is also important to begin actively cleaning up the space environment. This includes removing larger debris objects from busy areas before they can become debris that could pose a threat to spacecraft for decades. In April 2022 the Copernicus Sentinel-1A earth observation satellite had to make an evasive maneuver in order to avoid being damaged. A fragment of a rocket like this was launched 30 year ago.
ClearSpace-1 will be the first mission to remove a piece of space debris from orbit. The spacecraft will rendezvous to, capture, and safely bring down a 112kg rocket part that was launched in 2013. This will enable safe atmospheric reentry.
ESA will purchase the mission from Clearspace SA, a Swiss start-up, to demonstrate the technologies required for active debris removal. This is a first step towards establishing a new commercial sector in space dedicated specifically to the removal of high-risk objects from our limited orbital highways.
The 2022 Space Debris Environment Report is available in its entirety.