He hubble space telescopeone of the scientific wonders of humanity, launched into space with a defect that affected the quality of its images. However, the incredible feat of finding and applying a solution to this problem, coupled with the added challenge of performing the installation in mid-flight orbit, became a historic milestone.
Since its launch more than 33 years ago, the Hubble telescope has captured historic images and contributed to important discoveries in the field of astrophysics. At the beginning of his mission, a serious defect was discovered in its main mirrorwhose diameter reaches 2 meters 40 centimeters.
As it explains Very interesting, during the manufacturing and polishing process of the mirror, a spherical aberration was introduced that caused distortions and blurring in the images captured by the telescope. Although some of the images exceeded those obtained by ground-based telescopes, did not reach the quality required to justify the multi-million dollar investment made in the design, construction and launch of Hubble.
The problem was that the outer perimeter of the mirror had too flat a surface, causing light to reflect differently compared to light reflected in the center. While this didn’t significantly affect brighter objects, the loss of light caused problems when capturing dim objects or images that required higher contrast.
As a result, cosmological studies and observations of the ancient universe were being compromised, requiring a solution to be able to use the Hubble telescope as planned.
How did they fix it? With glasses”
NASA and the European Space Agency (ESA) opted for a corrective solution instead of complete replacement. A system was developed that compensated for the original error by using an identical but opposite defect, known as Corrective Optics Space Telescope Axial Replacement (COSTAR)..
In December 1993, during a Space Shuttle Endeavor mission, the corrective system was installed. The mission lasted 10 days and included the participation of six NASA astronauts and one ESA astronaut.
During five extravehicular activities, which totaled several hours of work, the corrective system was installed along with other electronic and computer improvements. This system worked like lenses for the Hubble telescope, correcting the defects of the main mirror..
It is important to note that telescopes like the James Webb cannot receive this type of enhancement. This is partly because they were not designed with the possibility of in-orbit repairs in mind and, in addition, their orbit around the L2 Lagrange point of the Earth-Sun system makes them difficult to access.