Welcome to the web pages of the Origins Billion Star Survey (OBSS). OBSS is an astrometric satellite designed to determine with unprecedented accuracy the positions, distances, and motions of a billion stars within our galaxy. It is a collaborative effort between the U.S. Naval Observatory (USNO) and several other institutions. OBSS will measure stellar positions to less than 10 microarcseconds. (To put this angle in perspective, the width of a typical strand of human hair would subtend 10 microarcseconds if you were viewing it from a distance of 650-900 miles.)