Hubble’s Redemption: A Tale of Precision, Blunders, and Unprecedented Space Repairs
In a daring and historic mission, NASA astronauts rescued the Hubble Space Telescope from an optical crisis nearly 30 years ago, allowing it to become the iconic and groundbreaking observatory we know today.
Back in 1990, Hubble was launched with faulty optics, resulting in blurry images that left astronomers and NASA baffled. The source of the problem traced back to a minute yet catastrophic error during the grounding of the telescope’s 2.4-meter mirror. Technicians, working tirelessly for three years, polished and measured the mirror to a precision of just five microns. However, an unnoticed flake of paint on a reflective null corrector led to a miscalculation, grinding the outer edge of Hubble’s main mirror too shallow by a mere two microns.
The consequences were severe—Hubble could only focus 15% of incoming light, causing distorted images due to spherical aberration. NASA faced public ridicule, but the solution turned out to be elegantly simple: glasses for the short-sighted telescope.
A team of seven courageous astronauts, including NASA’s Ken Bowersox, Dick Covey, Kathy Thornton, Jeff Hoffman, Story Musgrave, and Tom Akers, along with the European Space Agency’s Claude Nicollier, embarked on a perilous mission. Trained extensively in underwater buoyancy tanks, they executed five spacewalks, installing COSTAR (Corrective Optics Space Telescope Axial Replacement) to correct the spherical aberration and replace the original Wide Field and Planetary Camera.
On December 2, 1993, aboard the space shuttle Endeavour, the astronauts successfully saved Hubble in a flawless mission, marking the beginning of several servicing missions over the next 16 years. Ironically, COSTAR became obsolete as subsequent missions upgraded Hubble’s instruments, enabling them to correct for aberration independently.
While the James Webb Space Telescope has taken the spotlight, Hubble remains a vital contributor to astronomical discoveries. In the past year alone, it observed planetary weather, studied Saturn’s ring impact on its atmosphere, identified a double quasar from the early universe, and measured a nearby transiting exoplanet.
The heroic repair mission not only redeemed NASA’s reputation but also secured Hubble’s legacy, ensuring its remarkable contributions to space exploration over the last 30 years.