World's Toughest Fixes

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OverviewOverviewVideoVideoPhotosPhotosGameGameAbout the ShowAbout the ShowSean Riley and Jimmy FallonSean Riley and Jimmy FallonGot a Tough Fix?Got a Tough Fix?Sean Riley BioSean Riley BioReplace a Nuclear TurbineReplace a Nuclear TurbineReplace a Pressure DomeReplace a Pressure DomeReplace Damaged Power LinesReplace Damaged Power LinesRecoat a Telescope MirrorRecoat a Telescope MirrorSwap a Thirty-Eight Ton EngineSwap a Thirty-Eight Ton Engine

HOW TO... CLEAN AND RECOAT A 23-TON TELESCOPE MIRROR

Image: The transportation of the mirror in the World's Toughest Fixes' episode of 'Giant Telescope' from the National Geographic Channel

It takes an elaborate system of cranes and hydraulics to lift and transport the mirror and its housing, called the cell, which together weigh around 50 tons. First, the mirror and cell are moved onto a specialized carriage and placed onto a truck that travels an average of 3 mph on a mountain road to the cleaning facility. There, the bottom of the telescope mirror is cleaned of oil and dirt and the top is recoated with an extremely thin layer of aluminum in a vacuum chamber. Then the mirror is returned to the telescope in the observatory.

Technical Specifications:

The Atacama Desert in northern Chile has been called one of the driest places on earth due to sterile stretches where precipitation has rarely been recorded.
Two to three telescopes, each with 27-foot mirrors, can be combined to comprise the largest telescope in the world, called the VLT — which stands for Very Large Telescope.
The VLT can capture images from outer space in more detail than any others on earth. If one of the 27-foot mirrors on the VLT breaks, it could take four to six years to make another one.
The cell is more than just a housing for the mirror. It supports the mirror with 120 hydraulic pistons, called actuators, that precisely deform the mirror once per minute to correct for the distortion caused by gravity.
"First light" is what astronomers call the moment when the first light touches a telescope mirror, or in other words, the first time a telescope is ever used.

Can you handle a big fix? Try safely replacing a turbine yourself: Play Game >>

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