We developed the concept of two-stage optics in 1984 under the Jet Propulsion Laboratory's 20-m Large Deployable Telescope (LDR) program to enhance the performance, lower the cost, and increase the reliability of LDR. It permitted the large primary mirror to remain as deployed or as space-assembled, with phasing and subsequent control of the system done by a small, fully assembled optical active element placed at an exit pupil. The performance and tolerances of such a system were explored. A two-stage optics testbed was constructed that successfully demonstrated the concept. Extension of the concept for upgrading the perlormance of other large, low-cost, wide-field, space optical systems was explored. An opportunity to utilize this concept arose when the problems with the Hubble Space Telescope (HST) were discovered. Its advantages for use in future very large space telescopes are addressed.