Measures Against Space Debris: Mitigation, Tracking and Removal Strategies

Author: Space Economy Academy. In this article, we explore the most important measures against space debris, a growing problem that threatens satellites, spacecraft and the long-term sustainability of space missions.

Measures against space debris are becoming increasingly urgent. The growing amount of debris in orbit is one of the biggest dangers to satellites and spacecraft. If this trend continues, the rising risk and cost of sending expensive equipment, and even human life, into space will seriously affect the frequency and success of future missions. It is therefore a priority to curb this development by reducing the number of debris objects orbiting Earth and by taking effective action to reduce the risks they pose.

What Is Space Debris?

Space debris is defined as defunct human-made objects in space that no longer serve a useful function, particularly those in Earth orbit. These objects range from tiny fragments, such as solidified liquids expelled from spacecraft, unburned particles from solid rocket motors, and paint flecks, to large spacecraft, launch vehicle stages, and the vast amount of fragmentation debris produced when such bodies break apart.

Debris can be caused by a variety of events. Small parts may be accidentally released during satellite deployment or during orbital insertion manoeuvres. It may consist of satellites that fail to deploy properly, spacecraft that reach end of life, fragments produced by debris-on-debris collisions, impacts with spacecraft, or explosions onboard, such as battery failures. Several crewed and uncrewed spacecraft have already been damaged or destroyed by space debris.

Why Space Debris Is a Serious Threat

The number of tracked objects in orbit has grown dramatically. In addition to tracked satellites and larger fragments, there are vast numbers of smaller objects that are too small to monitor continuously but still large enough to cause severe damage. Estimates suggest there are tens of thousands of debris objects larger than 10 cm, more than a million between 1 and 10 cm, and many millions of smaller particles.

In Low Earth Orbit, objects travel at around 7 km per second. Because impact energy increases with the square of velocity, even a very small object can cause major damage to a spacecraft. This can render expensive systems useless, shorten satellite lifetimes, and create life-threatening situations for astronauts.

Another major concern is that collisions generate even more debris. When debris strikes another object, the resulting fragmentation can create a chain reaction that increases risk exponentially. With greater danger to spacecraft, the cost of space operations and launches rises. Existing satellites may also be forced to perform collision-avoidance manoeuvres, reducing fuel reserves and shortening their useful operational life. In the long term, if orbital risk becomes too high, access to space could become severely limited for years.

Main Measures Against Space Debris

So how can the space industry reduce the risk posed by space debris? There is no single solution. The most effective approach combines prevention, better tracking, and active remediation.

One possible measure is to minimise the risk of explosions after a satellite’s mission ends, for example by passivating the spacecraft and releasing stored energy sources. However, some of these processes can themselves generate additional particles, so they need to be handled carefully. Regulations are also being introduced at higher levels, such as requiring small satellites in Low Earth Orbit to deorbit within a defined time limit and discouraging the use of deployment systems that generate more debris.

Although efforts to reduce debris have seen some progress, they have not yet been sufficient to stop overall debris growth. In practice, the three broad categories of measures against space debris are:

• avoiding debris from being formed in the first place through mitigation,
• improving tracking and characterisation of debris,
• developing ways to remove existing debris through remediation.

Mitigation Measures Against Space Debris

Mitigation focuses on preventing new debris from being created. This includes better spacecraft design, safer deployment methods, passivation of satellites after mission completion, and stricter end-of-life disposal practices. Deorbiting defunct spacecraft more quickly is one of the most important and cost-effective mitigation methods, especially in Low Earth Orbit.

Recent analyses have shown that reducing deorbit timelines can significantly reduce long-term risk. Instead of allowing defunct spacecraft to remain in orbit for decades, shortening the disposal timeline can produce strong net benefits and help reduce the probability of future fragmentation events and collisions.

Tracking and Characterisation of Orbital Debris

Better tracking and characterisation are also essential measures against space debris. Improved Space Surveillance Networks and orbital data analysis allow operators to identify conjunction risks earlier, predict debris behaviour more accurately, and perform collision-avoidance manoeuvres when needed.

However, tracking alone does not solve the problem. It helps manage current risk, but it does not remove debris from orbit. This is why tracking needs to be combined with stronger mitigation and remediation strategies.

Debris Removal and Remediation Strategies

Debris remediation focuses on actively reducing the number of hazardous objects already in orbit. Recent cost-benefit studies have examined a range of remediation options, including moving debris, removing it, or reusing it in some way.

Contrary to earlier concerns that remediation would always require very high costs and long time frames before producing benefits, some studies suggest that certain remediation approaches may achieve net benefits in under a decade. Removing debris in the 1 to 10 cm range may produce benefits relatively quickly. Similarly, nudging larger debris objects away from possible collisions can generate benefits almost immediately by preventing fragmentation events before they happen.

Reusable spacecraft capable of forcing the largest debris objects down to Earth in a controlled way may also provide long-term benefits. For smaller debris, uncontrolled re-entry approaches may sometimes be less expensive than alternatives such as drag sails. Other ideas, such as recycling debris into propellant, are conceptually attractive because they could reduce the need for launching propellant from Earth, but the research and development costs remain high.

Cost-Effective Measures Against Space Debris

Recent policy and technology studies have highlighted two particularly important insights. First, debris remediation can be as cost-effective as tracking and mitigation in some scenarios. One of the most effective remediation concepts is just-in-time collision avoidance, where large debris objects are nudged away from potential collisions before fragmentation occurs.

Second, rapidly deorbiting defunct spacecraft appears to be highly cost-effective. Lowering the allowed deorbit timeline in Low Earth Orbit from decades to a much shorter period can generate significant benefits by reducing long-term exposure to risk. These measures against space debris are therefore not only technically relevant but also economically justified.

Why Long-Term Sustainability Depends on Action

By presenting detailed cost-benefit analyses, these studies aim to help governments and the space industry make informed decisions about which strategies and technologies to prioritise. Long-term sustainability in space depends on combining prevention, improved tracking, and active remediation in a coordinated way.

Without stronger and more widely adopted measures against space debris, the risks to satellites, spacecraft and future human spaceflight will continue to rise. The sooner these actions are implemented, the better the chances of preserving safe and affordable access to orbit.