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At present, the largest part of the catalogued space debris population consists of fragments originating from accidental explosions of spacecraft and upper stages, but it is expected that hypervelocity collisions involving large objects could become the primary source of new debris in the mid-term future. In this context, understanding the physical processes involved in spacecraft collisions is crucial, because these big impacts are one of the key drivers of the long-term evolution of the amount of space debris.

There is increased attention being given to safeguarding Earth's orbital environment, as reflected by the number of relevant regulations that are being set forward by national governments and international organisations. Among others, ESA has published a Space Debris Mitigation Policy for Agency Projects (ESA/ADMIN/IPOL(2014)2), supported by the corresponding ESA Space Debris Mitigation Compliance Verification Guidelines (ESSB-HB-U-002).

The main scope of this activity was to foster the exchange of expertise between the European Lidar Network (EARLINET) and Latin America Lidar Network (LALINET), and demonstrate the capability of joint research, setting the groundwork for GALION (The Global Atmosphere Watch Aerosol Lidar Observation Network) and future calibration/validation of ESA’s atmospheric satellite missions such as Aeolus and EarthCARE.

While the vast majority of space debris still stems from explosion events of satellites and rocket upper stages, current forecasts state that collisions, such as those between the Cosmos 2251 and Iridium 33 satellites in 2009, will play a dominant role in the mid-term future when a critical spatial density of satellites has been reached. In order to assess the risks emanating from space debris, a deeper understanding of the formation and residence time of breakup debris in orbit is essential for operational activities.