The Hubble Space Telescope launched in 1990 with the most perfectly polished mirror humans had ever made, ground to exactly the wrong shape by one-fiftieth the width of a human hair — a flaw too small

Hubble launched in 1990 with the most perfectly polished mirror ever made — ground to exactly the wrong shape by one-fiftieth the width of a hair, blurring every image. It took a shuttle crew three and a half years later to fly up and, in effect, fit the telescope with glasses. When the Hubble Space Telescope reached orbit in April 1990, it carried what was said to be the most perfectly polished mirror humans had ever made, and it was perfectly wrong. The outer edge had been ground too flat by about 2.2 micrometers, roughly... [8796 chars]