Measuring positions, distances, and velocities of stars in known tidal streams would enable measurement of the Galactic potential to an accuracy of one percent.

Phase space discovery of new tidal streams, remnants, and substructure.

Accurate measurement of the distance to the Galactic Center

Measurement of the Galactic rotation curve

proper motions of M31, the Magellanic Clouds, and other Local Group Galaxies.

internal kinematics in the Magellanic Clouds and other Local Group galaxies.

kinematics and ages of young stars in star formation regions

measuring accurate distances for individual stars in star formation regions (Taurus-Auriga, Orion) too faint to be observed by Hipparcos.

calibrating the absolute luminosities of "standard candles" such as Cepheids and RR Lyrae stars.

Conservative detection thresholds predict approximately 9500 extrasolar giant planets in the OBSS catalog detected through astrometric wobbles out to 200 pc, of which 7500 would yield orbit solutions.

excellent temporal coverage would enable detection of 2000 giant planets through transit photometry

OBSS would detect more than 80 percent of near asteroids with a radius greater than 140 meter

would provide a warning efficiency above 90 percent for hazardous objects

would detect hundreds of new Kuiper Belt and trans-Neptunian objects