Space debris has suddenly moved from being a remote and theoretical threat to the ever-increasing new space age, where mega-constellations and short launch cycles dominate, to be regarded as a high-risk environment rather than an optional concern for sustainability. Research has just emerged at the University of Surrey that presents this problem through a surprisingly different prism: that of circular economies. Professor Michael Dodge commented on this new approach with, ‘I’ve never seen it put this way. This is something that should be explored further.’
1. A Rapidly Escalating Orbital Crisis
Ever since Sputnik 1 was launched in 1957, there has been a steady accumulation of human-made junk, but the rate has grown exponentially in the last few years. “There are now more than 50,000 objects exceeding 10cm and over 1.2 million objects ranging from 1 to 10cm that orbit the planet at speeds of up to 7 km/s,” ESA reports. “There are already close to 8,000 satellites from commercial constellations like Starlink in orbit, and several tens of thousands that have received permission for launch.” Even without further launches, there will continue to be an increased number of objects for centuries, and there have already been cases where missions have been stranded due to space debris, causing damage to the ISS.
2. Circular Economy Principles in Space
The paper by the Surrey team published in *Chem Circularity* discusses the aerospace industry in the context of the theme of “reduce, reuse, and recover” to counter the status quo of use and discard in space exploration. The overwhelming majority of space exploration craft are currently developed with no plans for recovery, thereby discarding precious material when the craft reach the end of their lifespan. The principal author of the study explained: “A sustainable space industry with the same levels of success as electronics or car manufacturing would be mirrored if the industry focused on designing for serviceability.”
3. Waste Reduction and Launch Frequency
“Reduction” begins with design. Multisatellite launch systems, high-performance materials, or “collision avoidance” strategies could lengthen mission life and slow launch rates. Space-based “servicing” activities, including fuel replenishment, maintenance, or subsystem upgrades, provide “continuing” operation capability without requiring launch and landing on Earth. Active debris removal orbits, including net capture strategies and laser propulsion, have been successful in lower earth orbit. Now, “Zero Debris” missions necessitate dispositioning as part of new mission design as defined by “circularity’s first principle.”
4. Reuse: Extending Hardware Life
Reusability is exemplified through the repeated use of the Falcon 9 launch vehicles owned by SpaceX, now having been reused more than 260 times. The capsules and satellites are now able to be refurbished, reused, or repurposed for other tasks. New concepts are now emerging for satellites that are to be reused and are capable of carrying out the task of debris removal or material harvesting. This is despite the fact that the safety standards enforced by the space industry are very high; thus, the need for non-destructive testing before reusing the components.
5. Recycling in Orbit and on Earth
Recycling is difficult in space, but it is becoming more accessible. Space stations have already been recycling water and air in closed-loop life support systems; in the future, satellites could recycle debris to produce the raw materials needed to build products. Back on Earth, deconstructing old satellites to recycle the metals, composites, and perhaps fuel could be used to fuel new product development. Designs to recycle satellites in orbit are also being considered.
6. AI and Digital Twins as Sustainability Enablers
Historically, the lack of data has made space sustainability a challenged field, and AI is set to transform this. With machine learning, the failure predictions of satellite parts can be done, and plans can be made independently by the satellite itself in order to avoid collisions. Digital twins can be utilized in space because they don’t need the same level of physical testing, thereby decreasing development waste. In ESA’s PhiSat-1 mission, AI is utilized on board satellites to filter out unnecessary images.
7. Integrating Circularity into the Whole System
In this regard, the need for a systemic approach cannot be overemphasized. This can be derived from the process of the ISS de-orbiting to understand how fragmented decision-making affects the issue of reusing and recovering. Closing the loop on the basis of design and decommissioning phases regarding missions can enable the greatest potential for the achievement of sustainability goals.
8. Policy, Regulation, and International Collaboration
Current policies primarily target mitigation of debris and never tackle the subjects of resource recovery and orbital circularity. The target of the Surrey group is the establishment of binding global policies that address both sustainability and resilience. Experience from the European Union’s Action Plan for the Circular Economy can demonstrate how policy agendas can push the industry towards adapting positively, and these elements can be replicated in space. This is especially the case since the orbit itself is global.
9. The Physical Space Environment Factor
Another challenge that circularity has to face is space weather. While events like the Carrington event-level geomagnetic storms may render satellites useless, create cascades of space debris, and impact Earth’s critical infrastructure, making it more robust by starting basic space physics research, space monitoring missions, and including near-Earth space into Earth’s critical infrastructure is necessary. The meeting point of orbital debris mitigation strategies, design for the circular economy, and the use of AI optimization is an opportunity for the future of space sustainability. However, this opportunity is more than the application of engineering creativity and is intertwined with the sustainability of our Earth itself.