![](\"http:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2016\/11\/inspecting_jwst_s_primary_mirror\/16522453-1-eng-GB\/Inspecting_JWST_s_primary_mirror_small.jpg\")
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\nBefore a spacecraft goes into space it must undergo rigorous testing to confirm it can withstand the violent vibrations and sounds during launch.\n<\/p>\n
\nFor the powerful 6.5 m-diameter telescope of the James Webb Space Telescope, or JWST, making the same measurements both before and after a simulated launch is a vital part of confirming its optics will not be adversely affected by the real launch.\n<\/p>\n
\nIn a recent \u2018before\u2019 test, engineers made highly precise measurements of the shape of the main mirror in a \u2018centre of curvature\u2019 test.\n<\/p>\n
\nThey made detailed measurements of the mirror segments\u2019 shape and position by looking how light is reflected from them. Then they compare it with a reference that represents what the mirrors ideally should be. The technique allows any differences to be determined with incredible precision, and to ensure the mirrors are perfectly aligned.\n<\/p>\n
\nAfter the telescope has experienced the simulated launch conditions, the test will be repeated to confirm that the optics will indeed survive the rigors of launch.\n<\/p>\n
\nJWST is a joint project of NASA, ESA and the Canadian Space Agency, and is scheduled for launch in October 2018 on an Ariane 5 rocket from Europe\u2019s Spaceport in Kourou.\n<\/p>\n
\nThe observatory\u2019s broad goals include detecting the first galaxies in the Universe and following their evolution over cosmic time, witnessing the birth of new stars and their planetary systems, and studying planets in our Solar System and around other stars.\n<\/p>\n
\nThe test was conducted by a team from NASA Goddard, Ball Aerospace of Boulder, Colorado, and the Space Telescope Science Institute in Baltimore Maryland. This caption is based on the related NASA news item<\/a> featured on 2 November.<\/p>\n","protected":false},"excerpt":{"rendered":" \nBefore a spacecraft goes into space it must undergo rigorous testing to confirm it can withstand the violent vibrations and sounds during launch.\n<\/p>\n \nFor the powerful 6.5 m-diameter telescope of the James Webb Space Telescope, or JWST, making the same measurements both before and after a simulated launch is a vital part of confirming its optics will not be adversely affected by the real launch.\n<\/p>\n \nIn a recent ‘before’ test, engineers made highly precise measurements of the shape of the main mirror in a ‘centre of curvature’ test.\n<\/p>\n \nThey made detailed measurements of the mirror segments’ shape and position by looking how light is reflected from them. Then they compare it with a reference that represents what the mirrors ideally should be. The technique allows any differences to be determined with incredible precision, and to ensure the mirrors are perfectly aligned.\n<\/p>\n \nAfter the telescope has experienced the simulated launch conditions, the test will be repeated to confirm that the optics will indeed survive the rigors of launch.\n<\/p>\n \nJWST is a joint project of NASA, ESA and the Canadian Space Agency, and is scheduled for launch in October 2018 on an Ariane 5 rocket from Europe’s Spaceport in Kourou.\n<\/p>\n \nThe observatory’s broad goals include detecting the first galaxies in the Universe and following their evolution over cosmic time, witnessing the birth of new stars and their planetary systems, and studying planets in our Solar System and around other stars.\n<\/p>\n<\/p>\n