After launch, it was found that all of the images from the telescope were out of focus. An investigation found that the primary mirror of the telescope had been ground to the wrong radius, preventing the telescope from properly focusing. In December, 1993, the [[Space_shuttle|Space Shuttle]] Endeavor, during mission STS-61, captured the telescope and added a lens correcting for the defect in the primary mirror. Since then, the Hubble Space Telescope has been an invaluable tool to [[astronomy|astronomers]]. | After launch, it was found that all of the images from the telescope were out of focus. An investigation found that the primary mirror of the telescope had been ground to the wrong radius, preventing the telescope from properly focusing. In December, 1993, the [[Space_shuttle|Space Shuttle]] Endeavor, during mission STS-61, captured the telescope and added a lens correcting for the defect in the primary mirror. Since then, the Hubble Space Telescope has been an invaluable tool to [[astronomy|astronomers]]. |