Steven Griffin (Boeing), Christopher Wood (Air Force Research Laboratory)
Keywords: guidestar, telescope, vibration, jitter
Abstract:
A sodium guidestar will be incorporated into the AEOS 3.6 m telescope and is scheduled for completion in early 2014. The optical path of the guidestar includes a beam expander and transfer optics ending with a relatively large elevation flat before the laser beam is launched into the sky. The elevation flat is cantilevered off the elevation axis to maintain boresight with the telescope. While this simplifies alignment, it introduces a challenging structural dynamics problem since vibration of the cantilevered optic translates directly into guidestar jitter. Initial measurements of the elevation flat show that vibration levels are high enough to impact guidestar performance in relatively benign ambient conditions. To decrease this vibration, a tuned mass damper has been designed for the elevation flat and will be integrated into the system. This damper will significantly decrease vibration of the elevation flat by adding damping to the elevation flats first vibration mode. This paper will present the initial modal test results and vibration measurements that quantified current vibration levels and the analysis and line-of-sight modeling that were used to design the tuned mass damper.
Date of Conference: September 10-13, 2013
Track: Poster