This paper describes technology breakthroughs in solid divert propulsion that provide extensive mission flexibility to theater missile defense (TMD) interceptors over previous solid propellant divert systems. TMD interceptors must cover large battlespaces to minimize the total number of launchers and deployed missiles. They must defend against a broad set of targets, from short to long ranges. Effectiveness against current and emerging TMD targets is ensured when a fully controllable Divert and Attitude Control System (DACS) is used to maneuver the interceptor to impact. Operational requirements demand this DACS use solid propellant for user safety and cost minimization. Aerojet has recently accomplished several technology breakthroughs which demonstrate a solid DACS can be built with the mission flexibility of a liquid. This DACS called EXCELS (Endo, eXo, Controllable, Extinguishable, Lightweight, Solid), is the industry's first truly controllable solid DACS. Aerojet's EXCELS DACS has been under development since 1991 with IR&D funding Since then, four key development tests have been performed that validate the technology. Results are summarized in this paper. Aerojet is now supporting the BMDO, Navy and Army with contracts to further develop the EXCELS DACS for the SM-3 Block 2 Risk Reduction effort and the Atmospheric Interceptor Program (AIT). DACS development progress made on these programs in Winter and Spring 1998 are included in this paper.