Potential NASA Commercial Applications: This high accuracy tracker can be used for precision pointing of the large telescope. Its field of view is much wider than the fine guidance sensors (FGS) currently employed by HST and JWST. The JWST FGS, for example, has a field of view of only 0.04 x 0.04 degrees. With such a small field, fainter guide stars need to be used which then drives the sensor sensitivity and noise requirements. For the interferometric star tracker proposed, the angular sensitivity is defined by the angular period of the grating LSI, which can be independent of the field of view. This allows a wide field sensor to achieve similar level (milliarcsecond) of pointing performance, which then allows the use of brighter guide stars reduce the demand on sensor sensitivity. Another application is as reference sensor for laser beam pointing: A celestial reference based beam pointing eliminates the need for having a ground based beacon for return beam pointing which significantly reduces the operational complexity (power, pointing, regulatory compliance) and improves link performance (no round trip delay). OPC has also been funded recently for a study by JPL to investigate if its interferometric star tracker can be used for a spinning spacecraft. The study findings have shown the feasibility of adapting the interferometric tracker to provide accurate attitude information for a rapidly spinning spacecraft.