Engagement strategy provided to USSPACECOM component forces to achieve specific military objectives against a ballistic missile attack. It defines hostile target priorities, provides assets to defend, and allocates SDS resources to be employed. A number of DEOs may reside in a particular Preplanned Response Option (PRO). However, default DEOs (those believed to be best suited to counter the threat initially) will be automatically processed and executed when Defense Activation Authority (DAA) is given by USCINCSPACE.