Astrometric planet searches with SIM PlanetQuest

SIM will search for planets with masses as small as the Earth's orbiting in the `habitable zones' around more than 100 of the nearest stars and could discover many dozen if Earth-like planets are common. With a planned "Deep Survey" of 100-450 stars (depending on desired mass sensitivity) SIM will search for terrestrial planets around all of the candidate target stars for future direct detection missions such as Terrestrial Planet Finder and Darwin. SIM's "Broad Survey" of 2100 stars will characterize single and multiple-planet systems around a wide variety of stellar types, including many now inaccessible with the radial velocity technique. In particular, SIM will search for planets around young stars providing insights into how planetary systems are born and evolve with time.