European innovation makes crowded orbits safe
The challenges of space debris and increased space traffic require a multi-pronged approach. ESA’s Space Safety Programme outlines activities in its Council Ministerial 2025 proposal to help bring order to Earth’s busy orbits while supporting European industry.
Space is increasingly getting congested. Tens of thousands of satellites will be hurtling around Earth over the next decade, accompanied by well over a million > 1 cm pieces of debris. Tracking debris and avoiding collisions are an ever more essential – and costly – part of spacecraft operations.
The proposed ESA Space Safety activities will in the area addressing the increasing space traffic:
Make the problem concrete
A first step is to increase our understanding of the debris (and active satellites) in the space environment. Then, we can develop technologies for efficient space traffic coordination, helping to mature technologies from concept to demonstration.
Activities are grouped into four areas:
- Risk management technologies: Improving tools and methods to better predict and manage the risks both in orbit and on the ground from space debris and the increasing space traffic, feeding into spacecraft design and operations.
- Capacity monitoring technologies: Continue developing ways to measure and manage how crowded space is becoming, reflected for example in the yearly ESA Space Environment report and its new Health Index, helping ensure long-term sustainability.
- Support technologies: Creating tools and demonstrating readiness of processes for the mitigation of space debris, safe reentries and protecting dark skies.
- Observation technologies: Upgrading ways to detect and track space debris (especially small pieces that are hard to observe) and using this data to improve models like ESA’s MASTER.
Two promising debris detection technology projects are being prepared to go into space. Their data will improve the modelling of small debris in our space environment, like ESA’s MASTER debris model:
VISDOMS-S – Space debris is very hard to observe in the size range from sub-mm up to cm, yet these tiny objects can be lethal for mission. Aiming to fill the blind spot is Verification of In-Situ Debris Optical Monitoring from Space (VISDOMS-S), a small demonstration project focused on the optical detection of very small debris from space. From its space-based vantage point it will be designed to detect debris between 1 mm and 1 cm in size.
Sailor – Looking at even smaller debris is Sail Array for Impact Logging in Orbit (Sailor), with a smaller beta version called Optimist planned to sail ahead and test the waters. Once in space, the Sailor spacecraft will deploy two very large sails of a 25 m2 each that will be inspected for any tiny holes made by sub-mm (and up to a few cm) space debris fragments by cameras and sensors on the sails.
Improve collision avoidance
Once potential collisions are identified, spacecraft must be able to respond quickly and efficiently. ESA is exploring innovative methods to enhance collision avoidance capabilities.
CREAM – A particularly rich area of innovation is automation, with technologies that can help satellite operators respond more effectively to collision risks. At the heart of ESA’s effort is the Collision Risk Estimation and Automated Mitigation (CREAM) project. CREAM aims to reduce the workload of operators, the number of false alerts and the response time of collision avoidance measures, while improving mission safety. In the future, the system could also be used for supporting the coordination among operators. A small demonstration mission is planned to proof the developed technologies in orbit.
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Laser Momentum Transfer – A promising concept in the longer run is laser momentum transfer, which could allow for non-contact nudging of debris or satellites. A small amount of momentum can be imparted through photons, subtly altering its trajectory. If successful, this technique could be especially useful for adjusting the paths of defunct satellites and other debris without requiring a manoeuvre from healthy satellites.
Prevent new problems
Draco –As satellites reach the end of their operational lives in a low orbit, they need to vacate their orbit and reenter into the atmosphere to make space for new satellites. Right now, little data is available about the precise satellite breakup process and its effects on the atmosphere.
ESA’s Draco mission will collect unique measurements during an actual reentry and breakup of a satellite from the inside. A capsule especially designed to survive the initial destruction and transmit the valuable telemetry will help guide the development and validation of new technologies to build more demisable satellites for safer reentries.
LEMO demonstrator –As humanity prepares for sustained lunar exploration and increased activity in cislunar space, the need for coordinating space traffic grows with it. LEMO will apply lessons learned in Earth orbit to detecting and tracking human-made objects in the Moon’s vicinity.
Ensure our future in space
ESA’s Space Safety Programme aims to safeguard the future of space exploration through understanding the problem and developing technologies for a more sustainable future in space. By developing critical technologies and fostering collaboration with European industry, ESA’s Space Safety activities ensure that space remains a place of opportunity – bringing order to chaos.