The JWST Mirror — the heart of the telescope — is made up of 18 beryllium segments, each 1.5 m wide
Each mirror billet weighed 700 lbs. when loaded into one of the 8 Mitsui Seiki HMCs and 28 lbs. when machining was complete
Each mirror structure required 18 weeks of machining time
There are 8 different rib thicknesses on the 600-pocket side of the mirror structure ranging from 0.021 inch to 0.2 inch
Tolerances for mirror finishing are + 0.0002 inch / - 0.00 inches
True position is 0.001 inch from the inside to the outside of the hubs
True position is 0.005 inch all the way around the 48-inch bolt hole circle
The mirror surface has a specified thickness of 0.098 inch +/- 0.003 inch
Tolerances on the 32, 0.250 inch diameter holes on the edge is + 0.0002 inch / - 0.00 inch
Stability & Precision
Machining the James Webb Space Telescope Mirrors
What is the shape of the universe?
How did it build up its present elemental and chemical composition?
How do galaxies form and evolve?
How do stars and planetary systems interact?
All these mysteries and more will be answered by NASA's remarkable James Webb Space Telescope that will look deeper into space — and farther back in time — than ever before. The machining contractor that made the ultra precise mirror segments chose
Mitsui Seiki to supply the machine technology.
Learn more about this incredible project by watching the video below or reading our feature article in Manufacturing Engineering.
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