The Hubble Space Telescope - Now and then

The Hubble Space Telescope started out on Its mission of infamy and is now providing unparalleled information on the universe. Shortly after its launch in April 1990, the HST was found to have a problem with the primary mirror. After extensive analysis, it was concluded that serious spherical aberration was present caused by an improper manufacturing process and measurement of the surface. A servicing and repair mission was launched on Dec. 2, 1994 to correct and compensate for the primary mirror problem and also to replace other portions of the support systems on the HST. Since its repair, the HST has been providing information of astronomical events never previously considered possible and far exceeding any ground based telescope systems. This paper describes the telescope, its problems, and the corrections to compensate and improve the imagery from the HST.