Abstract: The LISA Mission proposal was selected by ESA’s Science Program Committee (SPC) for the L3 Cosmic Visions launch opportunity, and is currently in a Phase A mission formulation study. An essential component of the instrument is a set of optical telescopes that make precision displacement measurements between pairs of proof masses that are flying drag-free in three separate satellites. We discuss the key requirements on the telescope, the current design, and discuss progress toward solving some…