Lunar optical interferometerVarious design configurations of a lunar optical interferometer are examined to determine the interaction of science objectives and the architecture of an instrument that will have 10 microarcsec imaging resolution and 0.1 microarcsec astrometric accuracy. The imaging of the central energy source of AGNs, the discovery of earth-like planets around nearby stars, and the measurement of the proper motion of extragalactic objects to determine the isotropy of the Hubble expansion are some of the observations possible with a lunar interferometer. This interferometer with kilometric baselines and large collecting area will be able to make astronomical observations with angular resolution and sensitivity many orders of magnitude beyond orbital based or earth based instruments.