Space Debris

Primary reference(s)

Committee on the Peaceful Uses of Outer Space (COPUOS), 2002. Inter-Agency Space Debris Coordination Committee. Space debris mitigation guidelines. Official report A/AC.105/C.1/L.260. Accessed 25 February 2025

United Nations Office for Outer Space Affairs (UNOOSA), 2007. Space Debris Mitigation Guidelines of the Committee on the Peaceful Uses of Outer Space. Accessed 18 June 2024.

Annotations

Key relevant UN convention / multilateral treaty

Debris Mitigation Guidelines of the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS) (UNOOSA, 2010)

United Nations International Telecommunications Union (ITU) Recommendation ITU-R S.1003-2 (ITU, 2010)

Drivers

The primary sources of space debris in Earth orbits have been:

1. Accidental and intentional break-ups which produce long-lived debris and
2. Debris released intentionally during the operation of launch vehicle orbital stages and spacecraft (UNOOSA, 2007, COPUOS, 2024).

Impacts

Debris of greater dimensions than a few centimetres pose a hazard to operational satellites, the International Space Station, as well as other space stations in orbit.   The hazard not only stems from the mass of the objects, but also from the relatively high speed at which debris travels in outer space with respect to satellites and space stations.  Relative speeds in the order of 10 to 15 kilometres per second are typical for space debris (NASA, 2024). The European Space Agency (ESA, 2024) indicates that impacts of debris of the size of 10 cm and above on a spacecraft will most likely destroy the spacecraft. 

The environmental impacts of space debris include light pollution and re-entry depositing alumina into the upper atmosphere, with changes to solar radiation that could affect the Earth’s climate. In addition, there are risks of interference with communications infrastructure and functioning. It can also affect the ability to observe space.

Multi-hazard context

The figure below summarises common interactions between space debris and other hazards. This information should be used with caution and not be solely relied upon in Disaster Risk Management, particularly as some interactions may not have been included. Note that hazardous events occurring together or locally in space or time may not necessarily cause, amplify, or be otherwise related to each other. Specific examples of multi-hazard context can be found in the ‘Hazard drivers’ and ‘Impacts’ sections above.

Multi-hazard diagram

Risk Management

The origins of international efforts to address the challenges posed by space debris started at the end of the 1980s. These efforts stemmed from the explosion of the second stage of an Arianne 1 rocket in low-Earth orbit, creating more than 400 large pieces of debris. The Inter-Agency Space Debris Coordination Committee (IADC) was officially adopted in Moscow in October 1993. At the highest international level of the United Nations and recognizing the need to address the risk of space debris, the United Nations General Assembly endorsed the recommendation of COPUOS that the Committee’s Scientific and Technical Subcommittee (STSC) consider an item on space debris (COPUOS, 2003).  Since then, the topic of space debris is a regular agenda item of this Subcommittee. The Subcommittee established a dedicated working group to develop a set of recommended guidelines based on the technical content and the basic definitions of the IADC space debris mitigation guidelines and, taking into consideration the United Nations treaties and principles on outer space. At the recommendation of the Sub Committee, the Committee elaborated the Space Debris Mitigation Guidelines of the Committee on the Peaceful Uses of Outer Space, which were endorsed by the United Nations General Assembly In its resolution 62/217 of 22 December 2007 (COPUOS, 2008).   

The COPUOS guidelines for space debris mitigation are (UNOOSA, 2010): 

Guideline 1: Limit debris released during normal operations: Space systems should be designed not to release debris during normal operations. If this is not feasible, the effect of any release of debris on the outer space environment should be minimized. 

Guideline 2: Minimize the potential for break-ups during operational phases: Spacecraft and launch vehicle orbital stages should be designed to avoid failure modes which may lead to accidental break-ups. In cases where a condition leading to such a failure is detected, disposal and passivation measures should be planned and executed to avoid break-ups. 

Guideline 3: Limit the probability of accidental collision in orbit: In developing the design and mission profile of spacecraft and launch vehicle stages, the probability of accidental collision with known objects during the system’s launch phase and orbital lifetime should be estimated and limited. If available orbital data indicate a potential collision, adjustment of the launch time or an on-orbit avoidance manoeuvre should be considered. 

Guideline 4: Avoid intentional destruction and other harmful activities: Recognizing that an increased risk of collision could pose a threat to space operations, the intentional destruction of any on-orbit spacecraft and launch vehicle orbital stages or other harmful activities that generate long-live 

Guideline 5: Minimize potential for post-mission break-ups resulting from stored energy: In order to limit the risk to other spacecraft and launch vehicle orbital stages from accidental break-ups, all on-board sources of stored energy should be depleted or made safe when they are no longer required for mission operations or post-mission disposal. 

Guideline 6: Limit the long-term presence of spacecraft and launch vehicle orbital stages in the low-Earth orbit (LEO) region after the end of their mission: Spacecraft and launch vehicle orbital stages that have terminated their operational phases in orbits that pass through the Low Earth Orbit (LEO) region should be removed from orbit in a controlled fashion. If this is not possible, they should be disposed of in orbits that avoid their long-term presence in the LEO region. 

Furthermore, the International Telecommunications Union launched in 2010 its Recommendation for Environmental protection of the geostationary-satellite orbit (ITU, Recommendation ITU-R  S.1003-2 12/2010)  https://www.unoosa.org/documents/pdf/spacelaw/sd/R-REC-S1003-2-201012-IPDF-E.pdf, Accessed 25 June 2024) outlining the following measures to minimize space debris: 

Recommendation 1: That as little debris as possible should be released into the GSO region during the placement of a satellite in orbit;  

Recommendation 2: That every reasonable effort should be made to shorten the lifetime of debris in elliptical transfer orbits with the apogees at or near GSO altitude;  

Recommendation 3: That before complete exhaustion of its propellant, a geostationary satellite at the end of its life should be removed from the GSO region such that under the influence of perturbing forces on its trajectory, it would subsequently remain in an orbit with a perigee no less than 200 km above the geostationary altitude; 

Recommendation 4: That the transfer to the graveyard orbit removal should be carried out with particular caution in order to avoid RF interference with active satellites. 

Additionally, there are efforts to design space debris removal spacecraft. However, these are in the experimental stage only. Public space agencies and private companies are engaged in such efforts. To keep track of the implementation of space debris mitigation efforts, several Member States of the United Nations elaborated a Compendium of Space Debris Mitigation Standards adopted by States and International Organizations. The compendium compiles information on any legislation or standards adopted with regard to space debris mitigation. The compendium was last updated in April 2024 (UNOOSA, 2024). ITU has also implemented a dedicated webpage compiling links to guidelines, policies, legislation, best practices, and other measures implemented by international and regional organizations, and Member States of the United Nations. 

Monitoring

There is no international early warning system established by the space community to address space debris. However, specific space agencies are implementing measures that have many of the elements of people-centred early warning systems.

The United States Space Surveillance Network tracks space debris, and when there is a credible threat (probability in the order of 1 in 10,000), the network will alert the International Space Station so that the station can implement manoeuvres to avoid collision (NASA, 2024).

In 2013, the European Space Agency (ESA, 2013) reported that the Consultative Committee for Space Data Standards (CCSDS) released the first standard message format for sharing collision warnings. The new standard allows space agencies from different countries or regions around the world to share warnings using standardized texts.