April 24, 1990

The space shuttle Discovery, with a crew of five, lifts off on the 35th mission in the shuttle program. The next day, astronaut Steven A. Hawley releases the Hubble Space Telescope, an on-orbit observatory with great scientific promise. Although the telescope gathers unprecedented images, it proves to be somewhat myopic (exhibiting a two-micron-wide spherical aberration, something less than the width of a human hair) and will have to be repaired on a 1993 shuttle flight.