Validation of the corrective optics on the Hubble Space Telescope 1st Servicing Mission

The Hubble Space Telescope 1st Servicing Mission carried with it a total of 14 corrective mirrors, four in wide field (WF) 2 and the planetary (PC) 2 (three WF and one PC), two each for the three axial SIs (FOS red and blue), faint object camera (f48 and f/96), and Goddard high resolution spectrograph, which were packaged in a single module, corrective optics space telescope axial replacement (COSTAR). This paper presents the fabrication and validation of these mirrors that were the cornerstone of strategy to recover the telescope performance. The COSTAR optics were particularly challenging and represented one of the earliest examples of anamorphic aspheric mirrors fabricated to <0.005 waves RMS of surface figure residual. Other firsts included one of the earliest applications of phase stepping interferometry, now an industry standard. Insights into the corrective designs, the mirror figure shapes, and the technology used in the validation of the mirrors are presented.