Image Credit: Scientific Frontline
Scientific Frontline: Extended "At a Glance" Summary
The Core Concept: A computational modeling tool that incorporates space debris collision probability directly into the earliest design phases of Earth-observation satellite missions.
Key Distinction/Mechanism: Unlike traditional workflows where collision risk is assessed only after a satellite is designed, this framework links performance requirements (such as image resolution and coverage) immediately with physical constraints (size, mass) and orbital debris density. This allows engineers to see how specific mission goals—like higher resolution imagery—increase or decrease the statistical likelihood of a collision before any hardware is built.
Major Frameworks/Components:
- Variable Linkage: Connects optical requirements (resolution) directly to satellite physical dimensions (cross-sectional area).
- Orbital Mapping: correlates specific altitudes (e.g., 850–950 km) with both debris density and necessary satellite size.
- Trade-off Analysis: Calculates the safety "cost" of higher-performance data, revealing that higher orbits may carry greater risk due to the need for larger, more vulnerable satellite bodies.
Branch of Science: Aerospace Engineering, Astrodynamics, and Space Sustainability.
Future Application: The tool is expected to be used by mission planners to design "constellations" (groups of satellites) that optimize data gathering while minimizing the creation of new space junk. Future iterations may also account for debris reentry impacts and long-term orbital decay.
Why It Matters: It addresses the "space sustainability paradox"—the danger that launching more satellites to monitor Earth's environment could ruin the orbital environment. with over 100,000 satellites predicted by 2030, this tool provides a necessary method to ensure space remains usable for future generations.
Researchers at The University of Manchester have developed a new way to design Earth-observation satellite missions that could help protect the space environment while continuing to deliver vital data for tackling global challenges, such as climate change, food production, supply chain vulnerabilities and environmental degradation.
Earth-observation satellites are increasingly relied upon to support efforts to meet the United Nations’ 17 Sustainable Development Goals (SDGs), providing critical data on issues like land use, urban development, ecosystems and disaster response. However, the rapid growth of satellite missions is also making Earth’s orbits more crowded and hazardous, increasing the risk of collisions and the creation of long-lasting space debris.
There are currently around 11,800 active satellites in orbit, but some predictions suggest that number could rise to more than 100,000 by the end of the decade. Collisions in space can generate large amounts of debris, threatening satellites, astronauts, and the long-term usability of key orbital regions.
The new model, which links satellite mission objectives with collision risk as a key first step in mission design, is presented in the journal Advances in Space Research.
John Mackintosh, PhD researcher
Lead author John Mackintosh, PhD researcher at The University of Manchester, said: “Our research addresses what is described as a “space sustainability paradox”, the risk that using satellites to solve environmental and social challenges on Earth could ultimately undermine the long-term sustainability of space itself.
“By integrating collision risk into early mission design, we ensure Earth-observation missions can be planned more responsibly, balancing data quality with the need to protect the orbital environment.”
Many applications that support the SDGs rely on very high-resolution satellite imagery. To achieve this level of detail, satellites often operate at lower altitudes, which reduces their field of view. Alternatively, they can operate at higher altitudes but must be larger and heavier to carry bigger optical systems. This increases their exposure to space debris and makes collisions more likely and potentially more damaging.
The new modelling framework allows satellite performance requirements and collision risk to be considered together during mission design, rather than being assessed separately or late in development.
The approach links mission requirements, such as image resolution and coverage, with estimates of satellite size, mass, the numbers of satellites in a constellation, and the level of debris present in different regions of low Earth orbit. This allows designers to explore how different mission choices affect both data quality and collision risk.
Dr Ciara McGrath, Lecturer in Aerospace Systems
Using the model, the researchers found that collision risk does not simply peak where debris is most concentrated - satellite size also plays a major role. For example, for a satellite designed to deliver 0.5-meter resolution imagery, collision probability was highest between 850 and 950 kilometers above Earth - about 50 kilometers higher than the peak in debris density.
The study also found that although higher orbits require fewer satellites to achieve coverage, those satellites carry a greater individual collision risk because they are much larger. Lower orbits need more satellites, but each one can be smaller and therefore less hazardous.
Dr Ciara McGrath, Lecturer in Aerospace Systems at The University of Manchester, said: “As satellite use continues to grow, our method offers a practical way to ensure that space remains safe, sustainable and usable for generations to come, while still delivering the data needed to address the world’s most pressing challenges.”
Katharine Smith, Professor of Space Technology at The University of Manchester, added: “The method could also be adapted for different Earth-observation systems and expanded to include more detailed space-environment impacts. In future work, we could account for how long debris fragments stay in orbit, how likely they are to hit other satellites, and the wider environmental effects of satellite re-entry. This would allow mission designers to evaluate trade-offs across the full sustainability picture.”
Published in journal: Advances in Space Research
Title: Collision risk from performance requirements in Earth observation mission design
Authors: John Mackintosh, Katharine Smith, and Ciara McGrath
Source/Credit: University of Manchester
Reference Number: eng021626_01
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