Satellites support navigation, communications, weather forecasting and scientific research. They share Earth’s orbit with inactive spacecraft, discarded rocket stages and fragments produced by explosions or collisions.
This debris travels fast enough that even a small fragment can damage an operating spacecraft.
Where debris comes from
Orbital debris includes human-made objects that no longer serve a useful purpose. Common sources include:
- Satellites left in orbit after their missions
- Rocket bodies and released components
- Accidental explosions caused by stored energy
- Collisions between orbiting objects
- Destructive anti-satellite tests
A collision can produce many new fragments, increasing the probability of additional impacts.
Tracking reduces risk but has limits
Radar and optical telescopes monitor known objects and help predict close approaches. Satellite operators may move a spacecraft when a conjunction assessment indicates an unacceptable risk.
Tracking becomes more difficult as objects get smaller. Some fragments are too small to follow reliably but still large enough to damage equipment.
Crewed spacecraft and some satellites use shielding against tiny impacts, but shielding cannot stop every object.
Prevention is more practical than cleanup
NASA’s debris-mitigation practices emphasize preventing new debris, reducing the chance of accidental explosions and planning what happens after a mission ends.
Possible end-of-mission strategies include:
- Lowering a satellite so atmospheric drag eventually removes it
- Moving spacecraft away from heavily used orbital regions
- Releasing stored energy from batteries and fuel systems
- Designing hardware that does not shed unnecessary components
ESA’s 2025 space-environment report warns that objects left in operational orbits can fragment and create debris that remains for years.
Why removal is difficult
Proposed cleanup methods include robotic capture, drag devices and spacecraft designed to move large derelict objects. Each approach faces technical, financial and legal obstacles.
Debris may be tumbling, structurally unstable or difficult to approach. Ownership also remains relevant: an object does not become legally unowned simply because it no longer functions.
Removing selected large objects could reduce future collision risk, but cleanup cannot replace responsible design and disposal.
Orbit is shared infrastructure
The effects of debris cross national and commercial boundaries. One operator’s failed spacecraft can threaten satellites belonging to many others.
Sustainable access requires accurate tracking, information sharing, enforceable operating standards and responsible end-of-mission plans. Earth’s orbital environment is finite, and protecting it is necessary for the services that increasingly depend on space.
Sources
- NASA Orbital Debris Mitigation: https://orbitaldebris.jsc.nasa.gov/mitigation/index.html
- ESA Space Environment Report 2025: https://www.esa.int/Space_Safety/Space_Debris/ESA_Space_Environment_Report_2025
- NASA analysis of debris mitigation, tracking and remediation: https://www.nasa.gov/wp-content/uploads/2024/05/2024-otps-cba-of-orbital-debris-phase-2-plus-svgs-v3-tjc-tagged.pdf