A power system flexibly distributes power among phased array antenna apertures of a satellite (or other type of platform). By allocating the power provided by a power source among the apertures, if one aperture is not providing useful coverage (due to orientation, light traffic volume, aperture operating frequency and/or polarization, etc.), power being supplied to that aperture may be reallocated to one or more other apertures that are providing useful coverage. To flexibly allocate power among the apertures, power amplifiers and attenuators associated with each antenna element are adjusted to provide a wide range of RF output powers with high efficiency at all output power levels. By increasing power allocation efficiency, the size of the satellite power source may be reduced while appropriate power is still provided.