Astronomy Today

Space Telescopes

How was the Hubble Space Telescope repaired?

It took months to characterize and measure exactly what was wrong with the telescope. Once that was done, new solar panels were constructed, and special optical equipment was built to compensate for the aberrant optics. Principal among these plans were the Corrective Optics Space Telescope Axial Replacement (COSTAR), a set of three coin-sized mirrors that would bring light from the primary mirror into proper focus, and a new camera called the WFPC–2 (the second Wide Field/Planetary Camera).

The necessary servicing to the HST was conducted in December 1993 by four astronauts on the space shuttle Endeavour. They caught up with the Hubble two days after launch, and used the shuttle’s robotic arm to bring it into the shuttle’s cargo bay. For nearly a week, they conducted the necessary repairs and maintenance on the telescope. The first images that came down from the repaired telescope were transmitted early in the morning of December 18, 1993—and they were in perfect focus!

There was a profound difference in the quality of the images taken with the Hubble Space Telescope before (left image) and after (right image) its optics were corrected in 1993 by NASA scientists, engineers, and astronauts. (NASA)


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