Keeping aircraft safely separated is one of the core functions of air traffic management (ATM) today. As larger numbers of unmanned aerial systems (UAS) take to the skies, separation management becomes more important to avoid mid-air collisions. SPATIO is a three-year SESAR 3 JU project that addresses separation between unmanned air vehicles, in particular, strategic and tactical conflict resolution services and the relationship between separation and capacity in U-space airspace.