Progress on SIM-Lite brassboard interferometer integration and test

Main brassboard Michelson interferometer components have been recently developed for the future flight phase implementations of SIM Lite mission. These brassboard components include two fine steering mirrors, pathlength modulation and cyclic averaging optics and astrometric beam combiner assembly. Field-independent performance tests will be performed in a vacuum chamber using two siderostats in retro-reflecting positions and a white light stimulus. The brightness and color dependence of the angle and fringe tracking performance will be measured. The performance of filtering algorithms will be tested in a simulated spacecraft attitude control system perturbation. To demonstrate capability of a dim star observation, the angle and fringe tracking CCD sensors are cooled to -110 C using a cold diode heat pipe system. The new feed-forward control (angle and path-length) algorithms for the dim star observation will be tested as well. In this paper, we will report the recent progress toward the integration and performance tests of the brassboard interferometer.