Science promise and conceptual mission design for SAFIR: the single aperture far-infrared observatory

We report on completion of the SAFIR Vision Mission study, as organized by the NASA Science Mission Directorate. This study resulted in a focused baseline design for this large aperture space observatory that capitalizes on architectures being actively developed for JWST and other missions. Special opportunities for achieving thermal performance of this <10 K telescope are reviewed, as well as efforts to understand capabilities and needs for focal plane instrument and I and T on this large (10 m-class) telescope.