The year Hubble Space Telescope was launched; the serious flaw that was discovered when it began to send data; and how and when this flaw was fixed.

Question

The year Hubble Space Telescope was launched; the serious flaw that was discovered when it began to send data; and how and when this flaw was fixed.

Answer 1

The HST was launched in April 1990 from space shuttle Discovery.

The serious flaw is called spherical aberration, that resulted from too much glass being removed from the outer portion of the primary mirror during its manufacture.

This aberration was "fixed" during the first servicing mission in December 1993, by replacing one camera with a new camera containing corrective optics, and by replacing one of the four axial instruments with COSTAR (Corrective Optics Space Telescope Axial Replacement) that contained pairs of mirrors that removed the aberration for each of the three other instruments.