SIM is currently planned to be the first of the new origins missions. This
talk will describe the current status of the project and the observational
modes relevant to exoplanet detection and characterization. SIM directly
supports planet detection in a variety of ways. The most obvious is the
astrometric detection of planets. With a goal of 4 µarcsec astrometry
for global astrometry and 1 µarcsec for narrow angle astrometry, it
offers a bit more than a factor of 10 improvement over what is possible from
the ground using long-baseline interferometers. This paper will discuss the
two color technique for compensating for astrometric errors due to star spots
on main sequence dwarfs. In other areas, SIM is designed to provide a
technology demonstration of interferometric nulling for the future "planet
finder" mission. Nulling of a point source to 1¥10-4 at visible
wavelengths will require optical path stability comparable to 1¥10-6
nulling at 10 µm for the Planet finder mission. Last of all, this nulling
capability will enable SIM to study exo-zodiacal emission at visible wavelengths
at sensitivity many orders of magnitude better than what's possible from a
conventional large ground based telescope.
