The DPA Title III objective of the Phase 1 effort is the development and production of an affordable and reliable modular, Next Generation Star Tracker Systems (NGSTS) that uses advanced domestically-produced Complementary Metal Oxide Semiconductor (CMOS) detectors, with a capability that is equal to, or better than the specifications of DPA Title III Advanced CMOS Capability Project (see the STELLAR spec). For this purpose, the US Government (USG) considers a modular NGSTS to be capable of meeting a range of capabilities (i.e., environments, sensitivities, update rates, etc.), for a range of space-borne Medium-Accuracy Star Trackers (MAST: 1-20 arcsec), with the potential to also meet High-Accuracy Star Trackers (HAST: <1 arcsec) specifications, for both commercial and USG space applications, all from a single basic system design. A MAST designed to target a majority of the global technical requirements with a common architecture and/or footprint, is considered to be the baseline for the modular NGSTS design. Customization of electronics, software, optics, detectors, structure, etc. from baseline design will be required to meet specific program requirements.