Spherical aberration in its primary mirror (and other issues) discovered shortly after launch. https://www.skyatnightmagazine.com/space-missions/what-was-wrong

Spherical aberration in its primary mirror (and other issues) discovered shortly after launch. https://www.skyatnightmagazine.com/space-missions/what-was-wrong-with-hubble-mirror-how-was-it-fixed https://www.skyatnightmagazine.com/space-missions/what-was-w...