The primary focus of this effort is the development of a custom photon counting ROIC design for space optical communications. NASA?s Space The primary focus of this effort is the development of a custom photon-counting ROIC technology for use in space optical communications. NASA?s Space Communications and Navigation Program Office identified optical communications as an important technology for NASA missions, allowing enhanced volume and quality of data returned from the farthest reaches of space to be achieved in preparation for future human deep-space exploration missions. Although several missions have validated optical communications from low-Earth and geostationary orbit, the unique challenges of deep-space optical links still require separate risk-retiring technology demonstrations before implementing inner-orbit communication. The innovation will also enable a variety of other low-light-level and time-resolved imaging applications?including lunar and planetary hazard-avoidance and landing systems, automated rendezvous and docking in space, and in situ instrumentation.Time-resolved ROICs are at the core of optical communication and laser detection and ranging (LADAR) systems. On Earth, free-space optical communication transceivers are required to enable reliable two-way datalinks. Increased functionality in LADAR receivers enables adaptive cruise control, surveillance, restricted-area event alerts, object identification, day-night-rain-fog imaging, aviation takeoff and landing, mid-air refueling, terrain mapping, autonomous navigation, smart-intersection monitoring and control, unmanned ground vehicles, unmanned air systems and vehicles, machine vision, hazard material detection and handling, and underwater 3D imaging.