COCOA Readies for Cryogenic Testing

Narration: Conrad Wells

Transcript:

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This is the primary piece of measurement equipment that is going to verify the performance of the James Webb Space Telescope primary mirror. So this entire system is raised to the top of the Johnson cryogenic vacuum chamber where it's used to project light onto the primary which bounces back inside the optical system and we directly measure the performance of the primary mirror of the telescope

It accurately measures the height difference between the 18 segments and tells you the surface figure of the mirror to accuracies well below 1/10,000 of a human hair. If you took that primary mirror and made it the size of the United States and you had a mountain in the middle of it, we could measure the height of that mountain to the accuracy of a dime."

Inside this can is a computer generated hologram which is used to calibrate the optical performance of this system. And , since this system is used to test the performance of the primary mirror it's very important that this system also be calibrated. We're going to begin packing it up this week to send it too Marshall Space Flight Center to take it to the XRCF cryogenic vacuum chamber where we're going to do a full cryogenic vacuum thermal test on the system and verify its performance in those conditions.

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