This paper briefly describes optical design of the Hubble Space Telescope (HST) and overviews three optical design simulators for HST which have been proposed for use as verification tools to characterize the performance of second-generation instruments during ground testing. These simulators are: the Refractive Aberrated Simulator developed at Ball Aerospace, the Optical Simulator developed at Laboratoire Astronomie Spatiale, and the Jet Propulsion Laboratory Stimulus. Relative advantages and disadvantages of each optical configuration are discussed.
