Through its CleanSpace initiative, ESA has been devoting an increasing amount of attention to the environmental impact of its activities, including its own operations as well as operations performed by European industry in the frame of ESA programmes. In its Technology Strategy, ESA identified 'Inverting Europe’s contribution to space debris by 2030' as one of the four technology development targets.

The performed de-risk study revealed that space players are aware of the D4D constraints that one day may be standard rules for Space Agencies. The need to acquire in-flight data is considered of primary importance. However, costs and benefits of in-flight experiments shall be compared. From the analysis conducted by VKI it emerged that recurrent low-cost experiments could be a winning strategy considering i) the intrinsic stochastic nature of the space-debris phenomenon; ii) the reduced measurement capabilities compared to ground experiments; iii) the high risk of a big single experiment.

We have continued our shock physics code calculation studies of DART-like impact events. This includes comparisons of iSALE and SPH code calculations, using a range of strength and structural properties. The effect of porosity was studied in detail by applying different crushcurves, representing materials with varying crushing strength. The crushcurve was found to have a large influence on the outcome, in particular the ejecta properties and momentum transfer.

The objective of the Landmark ClearSpace-1 mission will be to demonstrate the complete value chain of active debris removal by removing an ESA-owned object (a VESPA upper part orbiting at an altitude of 500 km) by 2025.

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.

The technical objective of this study was to understand the net effect of using deorbiting technologies like sails or tethers over the future debris population around Earth. In principle, indeed, these attractive technologies will support the compliancy to post-mitigation disposal guidelines, for small missions. However, the increased cross section also increases the collision risk.

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 increase of space debris means that active space debris removal is becoming more relevant. An active debris removal mission would have a positive effect (or risk reduction) for all satellites in the same orbital band. This leads to a dilemma: each space agency has an incentive to delay its actions and wait for others to respond. We model this scenario as a non-cooperative game between self-interested agents in which the agents are space agencies.

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.