Orbital Debris: A Risk to Communications and Navigation

Orbital debris threatens communications and navigation satellites: a collision with a fragment can damage a spacecraft or disable it.

Orbital debris consists of defunct satellites and fragments of equipment that continue to move around Earth. Even a small fragment is dangerous at high orbital speeds; the more such objects there are, the harder it is to safely place and operate satellites.

How do collisions affect communications and navigation, and what measures can help reduce the risk?

How do orbital fragments threaten communications and navigation?

Orbital fragments threaten communications and navigation when they collide with working satellites: an accident can disable a spacecraft and produce new fragments.

Communications rely on satellite internet and other spacecraft in orbit, while navigation relies on GPS satellites. Damage to a satellite or the end of its operation can disrupt the service it provides; the consequences depend on which spacecraft is affected and what function it performs.

Why collisions can make the problem worse

When a satellite collides with a fragment, part of the spacecraft breaks apart, creating new fragments in orbit. These increase debris density in the same orbital region and pose an additional hazard to other spacecraft. This can trigger a chain reaction: each new collision leaves behind more debris.

The risk is not limited to communications and GPS. Debris can damage satellites used for scientific missions and complicate operations in the affected region. If the chain reaction continues, some orbital regions may become unusable, limiting both spacecraft launches and their operation.

How do collisions with debris damage active spacecraft?

Collisions with orbital debris damage active spacecraft: a fragment can puncture the hull or disable equipment. The Hubble Space Telescope has encountered debris; on one occasion, a fragment punctured its antenna.

This incident shows that debris is dangerous not only to satellites yet to be launched. Spacecraft already operating in orbit are also at risk: damage to an antenna can disrupt data transmission, while a malfunction in other equipment can interfere with a mission.

How damage affects services on Earth

If a satellite provides communications or navigation, damage to it can affect services that depend on its operation. These are the consequences of a specific spacecraft failing, not an inevitable shutdown of all communications or navigation systems.

The risk does not end after the first collision. The breakup of a spacecraft creates new fragments; as long as they remain in orbit, each one can collide with another satellite and increase the number of hazardous objects.

So damage to one spacecraft can have further consequences: the fragments remain a threat to other active satellites that communications and navigation depend on.

How are dangerous objects in orbit tracked?

Dangerous objects in orbit are tracked by comparing information about their position and movement with the trajectories of active satellites.

An object catalog helps track large fragments and assess where they are. Telescope observations supplement the catalog: they can identify debris that can then be included in assessments of the orbital environment.

How the risk of a close approach is assessed

For every potentially dangerous close approach, it is important to determine how the movement of the fragment and the satellite could lead to a collision. This assessment helps decide whether the spacecraft’s operation should be changed or its trajectory adjusted. The specific decision depends on the calculated risk and the satellite’s capabilities.

Catalogs and telescope observations reduce uncertainty in orbit assessments, but they do not provide complete control over every fragment. Monitoring helps detect a threat and prepare for a close approach; it does not change the fragment’s movement or remove it from orbit.

What measures can reduce the risk of orbital collisions?

The risk of orbital collisions can be reduced by preventing uncontrolled collisions between active satellites and debris, and by combining object monitoring with decisions by spacecraft operators.

Monitoring can identify a dangerous close approach, but does not itself change a satellite’s trajectory. The operator needs to assess the risk and decide whether to adjust the spacecraft’s movement. Connecting object tracking with operator action helps prevent new collisions and the creation of additional debris.

Coordination among operators

International coordination is important because orbital pollution can affect communications, navigation, and scientific missions. One operator’s decisions can matter to other spacecraft operating in the same orbital environment; sharing information about dangerous close approaches and coordinating action therefore makes practical sense.

Jin Xuan, Associate Dean for Research and Innovation at the University of Surrey, said: “There is now an opportunity to learn from other sectors.” The remark points to the possibility of bringing into the space industry coordination practices already used in other fields.

A practical step for operators is to take account of close-approach warnings and make decisions before a situation becomes uncontrolled. The more coordinated these actions are, the lower the chance that a collision will create new debris and increase the risk to communications, navigation, and scientific spacecraft.

Why is it legally difficult to remove someone else’s object from orbit?

Removing someone else’s object from orbit is legally difficult because ownership remains with the state or company that launched it. The Outer Space Treaty establishes this right of ownership even after an object stops working.

So identifying a dangerous fragment and being able to remove it are two different things. Orbital monitoring helps assess the risk of collision and take measures to keep an active satellite away from a dangerous close approach. But tracking does not grant the right to capture or move an object belonging to someone else.

Preventing collisions and clearing orbit

Collision prevention concerns trajectories: a satellite changes its movement to avoid encountering debris. Clearing orbit requires physically interacting with the object itself, so the ownership rights of the state or company that launched it must be taken into account.

Even if a technical method of removal exists, the owner’s consent remains a separate requirement. For any specific object, it is important to establish who owns it before planning to move or remove it.

Frequently asked questions