Shenzhou-20 was grounded after a particle under 1 mm punctured a window, prompting an uncrewed rescue return. Orbital debris is growing rapidly—ESA estimates >15,100 tonnes of launched material and millions of fragments that travel at ~7.6 km/s. Proposed removal concepts (harpoons, nets, service constellations, laser "brooms") face technical, environmental and political hurdles. Stronger governance, transparent data-sharing and scalable removal technology are needed to prevent future high-cost losses or casualties.
Space Debris Crisis: Will a Catastrophe Finally Force Global Action?
Artist's illustration of space junk orbiting Earth. | Credit: NASA
China’s routine crew rotations to the Tiangong space station were interrupted when engineers discovered a crack in a Shenzhou-20 re-entry capsule window caused by orbital debris. Ground analysts determined that a particle smaller than 1 mm had penetrated the glass layers, prompting officials to launch an uncrewed rescue return—Shenzhou-22—to bring the crew home rather than risk a standard crewed re-entry.
Why a Millimetre Matters
At typical low Earth orbital velocities of about 7.6 km/s (~17,000 mph), even millimetre-scale particles carry huge kinetic energy. That explains how a sub-1 mm fragment could puncture a thick capsule window and create an unacceptable risk to astronaut safety. As more launches—both governmental and commercial—increase the congestion in orbit, such strikes are likely to become more frequent.
How Big Is the Problem?
The European Space Agency (ESA) estimates more than 15,100 tonnes of human-made objects have been launched into space. Current estimates include roughly 1.2 million objects between 1 cm and 10 cm and about 140 million fragments
Notable Debris-Creating Events
Past incidents demonstrate the scale and persistence of the threat: China’s 2007 anti-satellite test that destroyed Fengyun-1C produced an estimated ~3,500 pieces; the 2009 collision of Kosmos 2251 with an Iridium satellite generated ~2,400 fragments; and Russia’s 2021 destruction of Kosmos 1408 created an estimated ~1,787 pieces, of which roughly 400 remain in orbit. These events remain hazardous for years to decades.
Technical Fixes—Promise and Limits
Several debris-removal ideas are being explored, but most are unproven at scale:
- Harpoons: Designed to snag large objects, but firing creates recoil risk and could produce more debris if not precisely controlled.
- Nets and Capture Arms: Can capture and de-orbit targets; however, single-use chaser missions are costly and fuel-intensive.
- Service Constellations: Proposed constellations of servicing satellites that regularly remove debris could be efficient long-term solutions but require major upfront investment and coordination.
- Laser Brooms: Ground-based lasers could nudge small fragments to lower orbits so they re-enter, but the technique is untested at scale and raises concerns about atmospheric effects and dual-use (weaponization) risks.
Governance and Geopolitics
Tracking and sharing orbital data are complicated by national security and commercial secrecy. China’s space program is overseen by its military, and many states treat certain satellite details as classified. The primary legal framework, the 1967 Outer Space Treaty (117 parties), established baseline principles but did not anticipate today’s crowded, commercialized orbital environment. Voluntary groups such as the Inter-Agency Space Debris Coordination Committee provide technical cooperation but cannot enforce binding obligations.
Why Policy Matters
Without stronger governance—transparent inventories, binding debris mitigation rules, and agreed enforcement—technical solutions alone will struggle to keep up with the rate of debris creation. Current ESA guidance recommends that satellites be de-orbited within 25 years of mission end, but compliance and practical recovery methods for small satellites (including cubesats) remain limited.
What Needs To Happen
Experts argue that preventing future debris and scaling removal require three complementary actions:
- Stronger international norms and binding rules to require end-of-life de-orbiting and accountability for fragmentation events.
- Investment in tested, scalable removal technologies and in-orbit servicing infrastructure rather than one-off retrieval missions.
- Improved transparency and data-sharing between nations and commercial operators, with safeguards for legitimate security concerns.
Bottom line: Orbital debris is an accelerating global hazard. It threatens satellites, human spaceflight and the long-term sustainability of space activities. Absent coordinated global action—legal, technical and diplomatic—the risk of high-cost satellite losses or even loss of life will grow, and may ultimately force a crisis-driven response.
