Surprising results from recent asteroid missions have highlighted the importance of testing planetary defence strategies in space, according to scientists participating in the joint ESA/NASA Asteroid Impact and Deflection Assessment (AIDA) collaboration. The unexpectedly large crater on asteroid Ryugu created by the JAXA Hayabysa2 impactor, together with the sand-like behaviour of material on its surface, further motivate the need to determine the effectiveness of proposed deflection techniques for an asteroid on a potential collision course with Earth. Implications are being discussed this week at the EPS-DPS Joint Meeting 2019 in Geneva.