Optical frequency combs are a unique laser source that combine wide spectral coverage with high coherence, permitting high precision optical measurements. This project aims to develop the technology for a growing list of applications, with a particular focus on important applications that lie outside the optical metrology laboratory. By taking advantage of components developed for optical telecommunications, project physicists have developed robust frequency comb designs capable of high-performance operation in the field outside the laboratory. They have demonstrated how pairs of combs can be used for chemical analysis and developed open-path atmospheric sensing techniques capable of precise and accurate measurements of atmospheric greenhouse and trace gases. They have demonstrated new methods for precision optical time transfer that can transmit signals from next-generation optical atomic clocks across long distances and enable next generation optical clock networks. They have shown how frequency-comb based LIDAR can provide absolute ranging with high precision as well as surface profiling. Finally, they continue to explore areas where the accuracy and precision of frequency combs can provide new capabilities in metrology and sensing.