How DLR deals with space debris

Space debris

Earth is surrounded by a cloud of debris – a DLR database shows both the number and the position of objects in space.
Credit:
DLR, AIUB

Space debris, or space junk, refers to all human-made objects in space that no longer serve any purpose, such as decommissioned satellites, rocket bodies or small components of these such as paint and varnish particles, screws, nuts and other small parts. The amount of space debris has increased significantly over the decades because of the space activities of various nations.

Approximately 45,000 objects larger than ten centimetres in diameter are regularly detected and catalogued. In addition, it is estimated that more than 1.2 million fragments of space debris between one and ten centimetres in Earth orbit. Because of high orbital speeds of several kilometres per second, collisions with even these small objects can cause severe damage to satellites, up to and including their complete destruction. This threatens the failure of important applications in communication, navigation, Earth observation, weather forecasting or the defence sector. In addition, avoidance manoeuvres are costly and consume propellant, which shortens satellites' operational lifespan. Orbital debris also poses a risk on Earth, as fragments can strike the planet's surface if they do not burn up in the atmosphere.

Should there eventually be too many pieces of debris in orbit, a phenomenon called the Kessler syndrome could occur. This refers to a cascading series of collisions, involving small or large pieces of debris and active or defunct satellites, with each collision generating more debris – leading to more collisions. As a result, individual orbital regions could become completely cluttered with debris, rendering them unusable for spaceflight for a long time.

Observing, removing and preventing space debris

DLR researches technologies for sustainable spaceflight and space debris mitigation. As part of this work, DLR space research investigates robotic technologies for extending the operational lifetime of satellites in space, as well as to actively capture and remove of space debris.

The best form of prevention, however, is to minimise the risk of failure or destruction of a space object from the outset, and to ensure that objects remove themselves from orbit independently at the end of their operational lifetime. Reusable launch systems and deorbiting technologies make important contributions here. For all satellite operators, it is essential to know which objects are close to their own satellites, so as to detect and avoid potential collisions in good time. This space situational picture, which the German Space Agency at DLR produces together with the Bundeswehr (German Armed Forces) at the Space Situational Awareness Centre, forms the basis for planning avoidance manoeuvres. To this end, both active objects and space debris are continuously tracked and catalogued.

Finally, we are active in international bodies working on regulatory measures to prevent space debris. At the same time, DLR researchers ensure that internationally recognised mitigation measures are considered and implemented in their own projects. As a signatory to the European Space Agency's (ESA) Zero Debris Charter, we are committed to the safe and sustainable use of space. This also means that no debris should be left in space after a mission has ended.

The following background pages offer an overview of our research activities and present technological solutions for satellite operations, robotics, debris detection, space weather and servicing.

Background articles

Space safety and security

Space infrastructure is the invisible backbone of our modern civilisation. Satellites not only enable global communication, navigation and weather forecasting, but also support areas such as disaster management, agriculture and transport. At the same time, the threat to this infrastructure from human-made and natural hazards is growing.

Observation of space objects

Detecting satellites and space debris, and determining their orbits precisely and reliably, helps to preserve space as a usable resource in the long term. To this end, we at DLR develop and use various methods and systems. Using highly accurate imaging techniques, we classify, identify and observe space objects, allowing us to detect changes in their flight behaviour, signs of ageing and structural changes at an early stage.

Removing space debris

Space debris poses a growing threat to spaceflight, as decommissioned satellites and debris resulting from collisions are increasingly cluttering Earth's orbits. This clutter increases the risk to active spacecraft and can also, in rare cases, pose a threat to people on the ground if debris that has not completely burned up during re-entry into the atmosphere falls to Earth.

Political initiatives and international guidelines

DLR is involved in several international bodies concerned with the regulation of space activities and mitigation of space debris. Two of these are of particular importance in an international context: the Inter-Agency Space Debris Coordination Committee (IADC) and the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS). The German Space Agency at DLR works within these bodies and ensures that the guidelines agreed there are implemented in German missions.

FAQ - questions and answers

The German Space Agency at DLR's FAQ page. The agency is actively involved in international committees and deals with a wide range of issues relating to 'space debris'.