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Giant Webb telescope unfolds as it travels a million miles away from Earth


Hubble has been the most productive
telescope in history but its successor the James Webb Space Telescope is
expected to surpass it in many ways– looking further back to when the
universe ‘s first stars and galaxies formed. And probing the atmospheres of planets around other
stars for signs of life. To meet these goals NASA and its
partners are building the biggest. most complex, and most expensive science
mission ever attempted. In the process engineers
have pushed technology to the limit –lighter and stronger mirrors, made of the
metal beryllium coated with gold for superior reflection of infrared light –heat insulation from a sunshield
the size of a tennis court and instruments that must work at a chilly
230 degrees C below freezing. And its so gigantic, that for launch the entire telescope must fold up
to fit inside the rocket. Once launched, Webb will set off on a
thirty-day 1-million-mile journey to its final orbital position, all the
while carefully unfolding itself. First, the solar array unfolds to power the
telescope. Then the communication dishes move into place. Next, the sunshield opens
protecting the delicate instruments from the heat of the Sun. Booms flip over revealing the secondary
mirror. And finally, the side tiles pop out to complete the primary mirror. Scientists will spend many weeks waiting
for the telescope to cool down, while fine-tuning the position and shape of
each of the 18 tiles in the main mirror. Only then, after two months in space will
the world’s biggest eye in the sky turn its gaze on the cosmos.

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