Page "Space Interferometry Mission" Paragraph 1

In addition to hunting for extrasolar planets, SIM would have helped astronomers construct a map of the Milky Way galaxy.

Other important tasks would have included collecting data to help pinpoint stellar masses for specific types of stars, assisting in the determination of the spatial distribution of dark matter in the Milky Way and in the Local Group of galaxies and using the gravitational microlensing effect to measure the mass of stars.