Keywords:interferometry; metrology; Space Interfermoetry Mission (SIM)
Publisher:Pasadena, CA : Jet Propulsion Laboratory, National Aeronautics and Space Administration, 2004
Citation:ICSO 2004 5th International Conference on Space Optics, Toulouse, France, March 30, 2004
Abstract:
The Space Interferometry Mission (SIM) requires fringe measurements to the level of picometers in order to produce astrometric data at the micro-arc-second level. To be more specific, it is necessary to measure both the position of the starlight central fringe and the change in the internal optical path of the interferometer to a few hundreds of picometers. The internal path is measured with a small heterodyne metrology beam, whereas the starlight fringe position is estimated with a CCD sampling a large concentric annular beam. One major challenge for SIM is to align the metrology beam with the starlight beam to keep the consistency between these two sensors at the system level while articulating the instrument optics over the field of view