Hubble Space Telescope

During the development of the Hubble Telescope, a PSL engineer worked continuously for years with the team building the High Speed Photometer (HSP). The HSP functioned as intended. Unfortunately the main mirror did not. (It was ground to an incorrect shape.) Because the HSP appealed to a narrower group of researchers than did other parts of the telescope, when it became necessary to fit the Hubble telescope with "corrective glasses", the HSP was chosen to be removed, to make space available in which to install the corrective optics. At the time it was removed, it was the only instrument aboard that had not suffered a failure of a major subsystem.