The Space Telescope program of the U.S. National Aeronautics and Space Administration (NASA) was approved by Congress in 1977. Named the Hubble Space Telescope in honor of American astronomer Edwin Hubble, it finally was launched from Space Shuttle Discovery on April 25, 1990. The stamp honoring the program was somewhat premature. Shortly after the telescope was deployed, the discovery was made that the primary mirror was flawed and could nor focus properly. Investigators finally tracked the cause of the error and repairs were made in 1993.