Some considerations for precision metrology of thin x-ray mirrors

Determination of the shape of very thin x-ray mirrors employed in spaced-based telescopes continues to be challenging. The mirrors' shapes are not readily deduced to the required accuracy because the mount induced distortions are often larger than the uncertainty tolerable for the mission metrology. In addition to static deformations, dynamic and thermal considerations are exacerbated for this class of mirrors. We report on the performance of one temporary mounting scheme for the thin glass mirrors for the Constellation-X mission and prospects for deducing their undistorted shapes.