Space debris

In early 2021, IRGC started a new project on assessing and managing risks related to space debris, in collaboration with the EPFL Space Center (eSpace) and EPFL Space Innovation. Addressing space debris is imperative for ensuring the sustainable use of space.

The problem

Space debris refers to anything non-functional left in space by humans. Pieces of debris can be as large as a bus-sized defunct satellite or as small as a paint flake. They include lost or abandoned spacecrafts, objects released during normal operations such as rocket bodies, lens caps, fairings and bolts, and fragments resulting from collisions and explosions.

There are currently almost one million of these uncontrollable debris objects larger than 1 cm, each bringing with it the danger of functional damage to operational satellites. This problem has been studied and discussed for the past 30 years but remains a source of concern, especially as space activities intensify. The forecasted increase in space traffic coupled with weak compliance with international space debris mitigation guidelines could dramatically increase the risk of in-orbit collisions. This could trigger a cascading effect if the number of objects in orbit goes above a tipping point, after which collisions among the debris and with operational satellites would generate more debris than the natural decay process can eliminate, threatening the safety of space operations.

While the issue of space debris might not seem dire to those of us on the ground, many vital services such as communication, navigation, banking transactions, environmental monitoring and weather forecasts all rely to some extent on space-based infrastructures.

Risk assessment

Estimating the risks posed by space debris is a complicated undertaking due to:

  • the complexity of the models used to predict collision risks and the long-term evolution of the space debris population;
  • uncertainty regarding the future of space activities and decisions taken by space actors;
  • ambiguity in the way that various actors in the space economy behave when confronted by the risk.

Risk management

Some options for space debris mitigation and remediation do exist but are costly. Their implementation requires cooperation between actors, willingness to share costs and a real motivation to act. Such motivation is currently missing, due to a lack of international regulation and liability, lack of incentives for collective action, and limited risk of reputational damage. Some regulations and guidelines exist, but overall response strategies have thus far been too modest. There is also a general perception that the costs of mitigation and remediation largely exceed the space debris related costs faced by satellite operators. But how true is this? The problem of space debris is marked by the possibility of catastrophic chain interactions, making collaboration in risk governance a critical priority.