When the Hubble Space Telescope was launched in 1990, it was hailed as the greatest astronomical instrument ever built. But when the first images returned to Earth, scientists were horrified. The pictures were hopelessly blurry. The telescope's primary mirror, the most precisely polished piece of glass ever created, had a microscopic flaw. The error was incredibly minute—the edge of the mirror was too flat by a fraction of the width of a human hair. This spherical aberration was caused by a faulty measuring device used during the manufacturing process, an error that went completely undetected because the manufacturer bypassed crucial secondary optical tests to save time and money. This book documents the engineering humiliation and the spectacular orbital rescue mission. You will explore the complex physics of optical calibration, the political fallout within NASA, and the ingenious invention of the COSTAR corrective lenses that essentially gave the telescope glasses. Look into the blurry depths of deep space. Learn how an invisible mechanical oversight nearly ruined a multi-billion-dollar project, and how human ingenuity fixed it in the vacuum of orbit.