Hubble launched in 1990 with a $1.5 billion price tag - and a mirror ground to the wrong shape. The error was just 2 microns off, about 1/50th the width of a human hair, but enough to leave the telescope nearly blind. NASA became a late-night punchline. In December 1993, astronauts spent 35 hours across five spacewalks installing corrective optics in orbit. The images that came back were perfect.
