Highlights • Analysis of new challenges raised to space debris mitigation by space cyber-attacks. • Mitigation measures should incorporate cyber security standard. • Platforms for space mitigation ought to be adapted to new circumstances. • Periodic review mechanisms ought to be established.

Abstract Growing possibilities and actual cases of cyber-attacks against space activities have brought about new challenges to overall space security and safety, aggravating, in all probability, the increasingly severe space debris problem. While space debris mitigation practices are recognized on both the international and national levels, their effectiveness differs, especially confronting space debris-generating cyber threats. Most current mitigation practices envisage only the debris-generating scenarios caused by internal reasons of the space objects, such as lousy design and manufacture, ignoring accidental disablements of space systems, collisions and break-ups caused intentionally by another party, which is the case of cyber-attacks against space activities. With more and more States finding it obligatory to adopt space debris mitigation measures, mitigating practice, if it has not evolved into, is at least on its way to customary international law. Facing new threats, some States and regions have already issued new policies to ensure the cyber-security of space activities, and further specific updates to the already outdated mitigating measures are also necessary. Incorporation in space debris mitigation practices of technical standards aiming to enhance space systems’ cyber-security standards, situational awareness, resilience, and physical robustness is thus of importance. It is also suggested that periodic review regimes and communication and coordination mechanisms between relevant standard-setting platforms be established in response to proliferating new risks in the space environment.