The increasing reliance on Earth-observation satellites to monitor critical global issues – from deforestation and urban sprawl to disaster response and agricultural yields – is creating a surprising problem: a growing risk of collisions in orbit. Researchers at The University of Manchester have developed a new approach to address this “space sustainability paradox,” aiming to balance the benefits of satellite technology with the long-term health of the space environment. The core of their perform focuses on reducing space satellite crashes.
These satellites are vital for tracking progress toward the United Nations’ 17 Sustainable Development Goals (SDGs), providing crucial data on land leverage, urban development, ecosystems, and disaster response. However, the sheer number of satellites being launched, coupled with the debris already orbiting Earth, is raising concerns about the potential for cascading collisions – events where one collision creates more debris, increasing the risk of further impacts. This escalating threat could ultimately render certain orbits unusable, hindering future space-based observation efforts.
The Manchester team’s research, led by PhD researcher John Mackintosh, proposes a method for linking mission requirements – specifically, the desired image resolution and coverage area – with the size of the satellite and the total number of satellites deployed. The study highlights a key trade-off: larger satellites, while requiring fewer units to achieve the same coverage, pose a greater individual collision risk due to their size and the potential for creating substantial debris fields. Conversely, smaller satellites, while individually less risky, necessitate a larger constellation to provide comparable data, increasing the overall probability of a collision.
Understanding the ‘Space Sustainability Paradox’
Mackintosh explained that their research directly tackles what’s been termed a “space sustainability paradox.” He stated, “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.” This paradox underscores the need for a more holistic approach to satellite deployment, one that considers not only the scientific or commercial goals of a mission but also its potential impact on the orbital environment.
The researchers found that while higher orbits require fewer satellites to achieve adequate coverage, those satellites carry a greater individual collision risk because of their larger size. This is due to the longer orbital periods and the increased velocity of objects at higher altitudes, meaning even a small collision can generate a significant amount of debris. The size of each satellite, the study confirmed, greatly impacts the chance of collisions.
The University of Manchester’s Commitment to Sustainability
The University of Manchester has established itself as a global leader in sustainability research and practice. According to the university, This proves the only institution in the world to consistently rank in the top ten for social and environmental impact in the Times Higher Education Impact Rankings. In 2025, the university ranked number one in the UK and Europe, and number two globally, for its overall social and environmental impact. The university also placed in the top 10 in the 2025 QS World University Sustainability Rankings (as of December 2024). More information about the University of Manchester’s sustainability initiatives can be found on their website.
This commitment extends to actively contributing to the UN SDGs through research, learning, public engagement, and responsible campus operations. The university’s five research beacons – advanced materials, biotechnology, cancer, energy, and global inequalities – exemplify its pioneering work in addressing some of the world’s most pressing challenges. Over the past five years, researchers at the University of Manchester have contributed 21,571 research publications across all 17 SDGs, representing 4% of the UK’s total research output on these goals.
SDG 10 and Global Inequalities
Recently, The University of Manchester was appointed as the UN Academic Impact Vice-Chair for SDG10 research, focusing on reducing inequalities within and among countries. This appointment highlights the university’s dedication to addressing global inequalities and leveraging academic research to inform policy and practice.
The university’s approach to tackling the SDGs is multifaceted, encompassing research impact, student learning, public engagement, and responsible campus processes. A comprehensive report detailing these efforts is available for download, offering a deeper dive into the university’s contributions to sustainable development. The full report can be accessed here.
As the number of satellites continues to grow, and the reliance on space-based data increases, the work of researchers at The University of Manchester offers a crucial pathway toward a more sustainable future in orbit. The next step involves further refining these models and collaborating with satellite operators and policymakers to implement these findings in real-world mission planning and regulatory frameworks.
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