2022/04/22
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in a nutshell
Our planet is surrounded by spacecraft that perform important tasks to survey our changing climate, provide global communications and navigation services, and answer important scientific questions.
But their orbits are churned with deadly debris from the past – fast-moving debris from defunct satellites and rockets trapped in orbit – threatening our future in space.
In 2002, the Interagency Debris Coordination Committee (IADC) issued Space Debris Mitigation Guidelines. The measures described in the guidelines dictate how space missions are designed, flown and retired in a way that prevents further debris generation. They are a big step towards protecting our critical orbit and have served as the baseline for space policy, national legislation and technical standards for 20 years.
Since 2016, ESA’s Space Debris Office has published an annual Space Environment Report to provide a transparent overview of global space activity and to demonstrate how these and other international debris mitigation measures will contribute to the long-term impact of spaceflight. We measure the extent to which we are improving sustainability.
Here are some of the key findings from the 2022 report:
detail
- More satellites are being launched today than ever before.
- This is driven by the increasing number and size of commercial satellite constellations in low earth orbit.
- Most, if not all, rocket bodies launched today are safely placed in compliant disposal orbits or removed from low-Earth orbit before breaking up into dangerous debris clouds.
- But today’s active satellites have to stay out of the way of objects that were launched decades ago and then fragmented.
- Not enough satellites are removed from the highly congested low-Earth orbit when they reach the end of their life.
- Advances in technology have improved our ability to locate and track small pieces of space debris.
- Our behavior in space is improving, but it’s still not sustainable in the long run.
Found over 30,000 pieces of space debris
The number of tracked space debris now exceeds 30 000
The amount of space debris in orbit continues to grow.
Over 30,000 pieces of space debris have been recorded and regularly tracked by space surveillance networks. As technology improves, we see the number of Unidentified Objects (UI) increasing. Due to the time elapsed between their creation and our observations, it is difficult to trace their origins to specific ‘fragmentation events’.
Based on the ESA model, the actual number of objects larger than 1 cm in size could exceed 1 million.
Small satellites; larger constellations
Satellite constellations are growing in number and size as technology becomes more reliable and compact
The 2020s ushered in a new era of spaceflight.
The technology required for large satellite constellations has rapidly become reliable and compact. As a result, the past two years have seen a significant increase in the number of commercial satellites launched into near-Earth space. The majority of them are small satellites weighing between 100 and 1000 kg.
Many of these constellations are launched to provide communications services around the world. While they offer great advantages, they pose challenges to long-term sustainability.
More satellites sharing rides
Space travel used to be lonely, but now many satellites are in orbit with rideshares.
Constellations are also changing the way satellites reach space. In 2021, a record number of rocket rockets will launch multiple satellites into orbit simultaneously. While this reduces launch costs per satellite, it often makes it more difficult for surveillance networks to locate and track individual objects.
Low Earth orbit is crowded
The number of close encounter alerts received by satellites in low earth orbit is increasing year by year.
Increased launch traffic and the long-lasting nature of space debris in low-Earth orbit have resulted in a significant number of close encounters, known as “couplings,” between active satellites and other objects in highly congested orbits. is occurring.
This plot shows the number of times common satellites experienced possible collision alerts at various altitudes in 2021.
At lower altitudes, satellites encounter smaller satellites and constellations more often. At higher altitudes, we often encounter debris objects left over from a few well-known and significant fragmentation events. This is shown in shades of blue in this plot.
Not all alerts require avoidance action. But as the number of alerts grows, it becomes impossible for spacecraft operators to respond to them all manually. ESA is developing automated systems that use artificial intelligence and other technologies to help operators perform “collision avoidance maneuvers” and reduce the number of false alarms.
we are making progress in several areas
Many rocket bodies launched today are being disposed of responsibly
One of the positive things about the debris environment is that many of the rocket bodies launched today to carry satellites into low earth orbit are being disposed of in a sustainable manner. Some will be burned up using a “controlled re-entry” into the Earth’s atmosphere, while others will be placed in orbits where they will naturally decay within 25 years.
Rocket bodies are the largest objects we send into space, and removing them from busy orbital highways reduces the chances of them exploding or splitting into many pieces of dangerous debris. .
At the end of the mission, more satellites should be responsibly scrapped
A growing number of satellites have completed their missions in low earth orbit and are being responsibly disposed of, but there is still work to be done. The rate of successful disposal attempts is increasing, but too much waste is adrift in critical orbits and unattended to be removed.
To reduce the growth rate of space debris, the removal rate of all types of space objects should reach at least 90%.
but there is more to do
Our current behavior could make some orbits less livable in the future
We may be more responsible for what we launch today, but our current efforts are not enough.
“Extrapolating” current behavior into the future shows how the number of catastrophic in-space collisions will increase if we do not significantly change how space objects are used to launch, fly, and dispose.
In the long term, this can lead to “Kessler Syndrome”. This is a situation in which the density of objects in orbit is high enough that collisions between objects and debris create a cascading effect, with each collision producing debris and increasing the likelihood of further collisions. At this point, certain low-Earth orbits become completely uninhabitable.
it’s time to act
The most effective way to avoid this situation is for more space stakeholders to follow IADC’s Space Debris Mitigation Guidelines. That means doing more to prevent orbital detonations, avoid orbital collisions, and safely dispose of spacecraft at the end of missions.
Another necessary step is to initiate an aggressive cleanup of the space environment. First, remove existing larger debris objects from crowded areas before they disintegrate into debris that threatens spacecraft decades later. In April 2022, the Copernicus Sentinel-1A earth observation satellite had to perform an evasive maneuver to avoid it. Fragments of a rocket launched 30 years ago.
ClearSpace-1 is the first mission to remove space debris from orbit. The spacecraft rendezvous with, captures, and safely unloads 112 kg of defunct rocket parts launched in 2013 for safe atmospheric re-entry.
ESA has purchased a mission-as-a-service from Swiss start-up Clearspace SA to demonstrate the technology needed for aggressive debris removal and develop a new sustainable commercial space vehicle dedicated to the removal of high-risk objects. Our precious and limited track highway as a first step to establish the sector.
Read the full 2022 Space Debris Environmental Report.
