ASYRIO is a development program, carried out at CASA's facilities under an ESA (ESTEC) contract. The objective is the technological development of reconfigurable microwave devices, and their application to an antenna system for communications satellites with flexible-coverage illumination and reconfigurable missions. The associated hardware consists of an antenna-feed demonstration model, and a set of space-qualified reconfigurable components. These are to be capable of operation in space conditions, and reconfigurable through software control from an earth master station. A scenario has been tried for the second generation of Spanish-telecommunication satellites. This scenario is the fundamental input for antenna-system requirements. It presents supranational-coverage characteristics. It is for use where a flexible mission is needed or desired; detailed analysis of each particular case shows the more-appropriate reconfiguration implementation. A multibeam-reflector antenna has been accepted as the baseline for a high-gain-antenna definition, with a fixed-parabolic reflector, and a reconfigurable multibeam-feed subsystem. Reconfigurability is accomplished by the variable components assembled in the feed beam-forming network. The feed-demonstration model that supports the Spanish mission has been designed, manufactured, and tested, both electrically and thermomechanically, to verify its compliance with space geostationary environmental conditions during and after launch.