Overview:

The Space Interferometry Mission (SIM) will be an optical interferometer operating in an Earth-trailing solar orbit. In its final orbit the spacecraft will slowly drift away from the Earth at a rate of approximately 0.1 AU per year, reaching a maximum communication distance of about 95 million kilometers after 5.5 years. In its orbit the spacecraft will receive continuous solar illumination, avoiding the occultations which would occur in Earth orbit.

Objectives:

SIM PlanetQuest will address:

• Astrometric search for brown dwarfs, massive planets, and terrestrial planets around nearby stars.

• Search for newly-formed planets around young stars.

• Masses and evolution of stars in close binary systems.

• Accurate masses of low-mass binary stars.

• Internal dynamics and ages of globular clusters.

• Mass distribution in the halo of our Galaxy and its spiral structure.

• Dynamics of our Local Group of galaxies includig dwarf spheriodial galaxies and tidal tails.

• Proper motions of nearby active galactic nuclei and the question of binary black holes.

Instrumentation:

• A science interferometer with 9 meter baseline.

• Two guide interferometers with 7.2 meter baseline.

• Optics with 325 cm² collecting area.

• Operational limiting magnitude down to 20 at 20 µas.

• Terrestrial planet-finding astrometric accuracy of 1.12 µas (single measurement).

• Global astrometric grid accuracy of 3.47 µas.