Expert Comment: From frontier to feedback loop - Why space must become circular

Dr Yige Sun

Space is no longer an empty frontier; it is now essential infrastructure, and like all infrastructure, it carries environmental consequences. But rapid commercial expansion raises a pressing question: can the space economy become circular before congestion makes it brittle?

Why has space become so crowded?

For decades, space missions have followed a linear model: launch, operate, discard. This approach was tolerable when launch frequency was low and orbital density manageable – but this is not the case now.

Orbital space is governed largely by voluntary guidelines. Disposal rules lack enforcement, and liability frameworks designed for state-led missions struggle to address today’s commercial, multi-actor environment.

Launch costs have fallen sharply over the past decade, with the cost of reaching Low Earth Orbit (LEO) plummeting from roughly $54,500/kg during the Space Shuttle era (1981-2011) to approximately $1,400/kg with the SpaceX Falcon Heavy in 2018, a 95% reduction. This has brought us into the era of the ‘mega-constellation’ - perhaps best illustrated by Starlink. As of late 2025, Starlink comprised approximately 9,400 satellites - a staggering 65% of all active satellites in orbit and roughly 52% of all mass in LEO.

With thousands of operational satellites in LEO and tens of thousands more planned, the problem is not merely aesthetic clutter. It is systemic risk. According to the European Space Agency (ESA), as of January 2026, there were about 14,200 active satellites in orbit, yet these are shadowed by over 54,000 tracked debris objects (greater than 10 cm) and an estimated 1.2 million dangerous fragments between 1cm and 10cm (with another 140 million between 1 mm to 1 cm).

Orbital debris travels at speeds of up to 10 km/s (10 to 20 times faster than a bullet), with collision speeds reaching 14–15 km/s. This means that even small fragments carry destructive energy. ESA’s Space Environment Health Index currently sits at a concerning level of 4, far exceeding the threshold of 1 required for long-term orbital sustainability.

Despite these risks, orbital space is governed largely by voluntary guidelines. Disposal rules lack enforcement, and liability frameworks designed for state-led missions struggle to address today’s commercial, multi-actor environment. This encourages risk externalization: operators deploy rapidly and long-term stewardship becomes a secondary cost.

Durability is sustainability

On Earth, circular economy principles seek to decouple growth from resource depletion through reuse, repair, remanufacture and material recovery. In orbit, this means shifting from disposable satellites to serviceable, upgradeable and recoverable assets. Recent research estimates that recovering and reusing orbital debris could unlock a net material value of between $570 billion and $1.2 trillion.

The Satellite Applications Catapult’s In-orbit Servicing, Assembly and Manufacturing (ISAM) test bed. Credit: Satellite Applications Catapult.

My recent work with Mr Gary Cannon and Mr Mike Curtis-Rouse at the Satellite Applications Catapult establishes that serviceable satellite and spacecraft architectures - modular systems, traceable material interfaces and robotic-compatible access points - can significantly extend operational lifetimes and enable in-orbit upgradeability. This work provides a critical link between high-level UK policy ambitions, such as the National Space Strategy (2021) and the Rendezvous and Proximity Operations Regulatory Sandbox (2025), and the actionable engineering principles required for serviceable system design. Sustainability is not an end-of-life correction, but a core requirement embedded at the design inception. By addressing these vulnerabilities early, satellites can be transformed from disposable units into maintainable infrastructure assets.

Life-cycle thinking must begin before launch. The environmental footprint of a satellite is embedded in material extraction, cleanroom fabrication and launch emissions. These decisions must be integrated at the architecture stage rather than retrofitted later.

Additionally, there is a burgeoning market for approaches that harness in-space manufacturing; reusing and servicing satellites already in orbit and – in the future - manufacturing new materials directly in space that benefit from the microgravity environment. This sector generated $4.4 billion in revenue in 2023 and is projected to grow at a compound annual growth rate of 20% from 2024 to 2032.

Beyond hardware: The governance challenge

There is a burgeoning market for approaches that harness in-space manufacturing; reusing and servicing satellites already in orbit and – in the future - manufacturing new materials directly in space.

But the challenge is not merely engineering; it is institutional design.

Legal frameworks built in 1967 (Outer Space Treaty) and 1972 (Liability Convention) were not designed for proximity operations, robotic servicing or shared orbital infrastructure. Governance lag creates uncertainty for investors and discourages adoption of circular practices.

Without regulatory clarity, circular practices remain voluntary, allowing competing actors to externalize costs. A circular space economy requires enforceable disposal norms, transparent debris tracking, clearer liability allocation and incentives that reward life extension over replacement.

The economic logic for circularity is already clear. As satellite deployment accelerates, congestion imposes a ‘debris tax’ through increased manoeuvres, insurance premiums and shortened operational lifetimes. In 2025 alone, Starlink satellites executed approximately 300,000 collision avoidance manoeuvres, a 50% increase from 2024, demonstrating the immense fuel and management burden of a hyper-congested environment. The World Economic Forum projects that debris-related costs could reach $42.3 billion over the next decade if unmitigated. Circular design reduces exposure to these risks by stabilising the shared orbital environment.

Space is the next internet

Space has evolved into a critical layer of global infrastructure. Infrastructure that cannot circulate resources, manage risk and renew itself ultimately collapses under its own growth.

Much like the early internet, space activity is now expanding beyond its initial boundaries in LEO, with lunar communications networks, logistics platforms and resource extraction under active discussion. If linear extraction models are exported beyond Earth before circular governance frameworks mature, congestion and conflict risks may scale with expansion.

Sustainability in space is not about slowing innovation. It is about preventing systemic fragility.

Space is no longer an experimental domain. It has evolved into a critical layer of global infrastructure. Infrastructure that cannot circulate resources, manage risk and renew itself ultimately collapses under its own growth.

Space circularity is therefore not environmental idealism. It is strategic self-preservation.

You can read the report ‘Technical Considerations for Serviceable Spacecraft’ co-authored by Dr Yige Sun, here.

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