Creare and Embry-Riddle Aeronautical University (ERAU) propose to complete the design, development, and testing of an ultra compact star tracker specifically intended for small satellites such as the CubeSat platform. Our design is based on proprietary "folded optics" technology previously developed by ERAU for use in military and commercial optical applications that require a compact footprint and high performance. Furthermore, the design utilizes recent advances in high pixel count CMOS imaging sensor technology. The folded optics design is superior to conventional refractive optics in miniature star trackers because (1) the compact footprint is achieved without sacrificing accuracy; (2) the light-gathering aperture is much greater, leading to better sensitivity; (3) the aperture geometry makes the shielding baffles smaller; and (4) the imaging sensor can be shielded efficiently from cosmic radiation. During the Phase I project, we demonstrated a pointing accuracy of the order of 1 arc second testing a brassboard model of our design. We furthermore completed the design, performed analysis to determine the optimal design parameters, and confirmed the brassboard sensitivity and resolution. In Phase II, we will fabricate the optimized design, test the prototype in the laboratory and in the field, and deliver the prototype to NASA so that NASA can fly the prototype on a NASA high-altitude balloon mission.