Missions to solar system bodies must meet increasingly ambitious objectives requiring highly reliable soft landing, precision landing, and hazard avoidance capabilities. Robotic missions to the Moon and Mars demand landing at predesignated sites of high scientific value near hazardous terrain features, such as escarpments, craters, slopes, and rocks. Missions aimed at paving the path for colonization of the Moon and human landing on Mars need to execute onboard hazard detection and precision maneuvering to ensure safe landing near previously deployed assets. Other NASA applications include freespace optical communications, laser radar (LADAR), LIDAR, and time-resolved imaging. Commercial applications include automotive collision avoidance, gesture recognition, LIDAR, altimetry, neonatal imaging, time-resolved spectroscopy, fluorescent decay measurements, single-photon detectors, auto- and cross-correlation.