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The James Webb Space Telescope is moved inside this massive cryogenic vacuum chamber at NASA’s Johnson Space Center called Chamber A.

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This chamber simulates the vacuum and super cold environment of space in which Webb will operate

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about 40 K or about minus 388 degrees Fahrenheit or minus 233 degrees Celsius

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The Webb telescope mission team uses Chamber A to further verify the entire telescope, including its optics and instruments, will work correctly in space.

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Part of this test includes aligning Webb’s 18 mirror segments into a perfect, monolithic mirror.  

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The process is similar to the way the mirrors will be aligned in space.

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Actuators behind each mirror enable the aligning, or “phasing,” of the telescope’s 18 hexagonally shaped primary mirror segments to function as a single 6.5-meter mirror.  

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The mirror’s actuators can move in steps that are a fraction of a wavelength of light, or about 1/10,000th the diameter of a human hair. 

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In space, a star will be used to as the light source to align the mirrors.  

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Engineers will move each mirror and determine which image is coming from which mirror.  

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Then, through a process called Wave Front Sensing and Control, the mirrors will be aligned and very finely focused 

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For this test, the Webb team uses a special laser to act as the ‘star’ and a test device called a multi-wavelength interferometer.  

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By analyzing the interference signal between these two light beams, engineers determine the mirror shape and the alignment of the mirrors to within one wavelength of light.  

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The James Webb Space Telescope is the scientific complement to NASA's Hubble Space Telescope. 

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It will be the most powerful space telescope ever built. 

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Webb is an international project led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.

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music. beep. beep.