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How the James Webb Space Telescope beat all expectations


On Christmas Day of 2021, the James Webb Space Telescope launched from Earth into space. With an expected 6-month deployment, the mission's plan was to begin science operations afterwards and to have a 5-to-10 year science lifetime. At every turn, however, the Webb Telescope team has beaten expectations. After barely 4 months, it's practically ready, with perhaps 20 years of science ahead of it.


Although Spitzer (launched 2003) was earlier than WISE (launched 2009), it had a larger mirror and a narrower field-of-view. Even the very first JWST image at comparable wavelengths, shown alongside them, can resolve the same features in the same region to an unprecedented precision. This is a preview of the science we'll get. (Credit: NASA and WISE/SSC/IRAC/STScI, compiled by Andras Gaspar)


The plan envisioned six months of deployment, cooling, and calibration.


Afterwards, science operations would commence, yielding a 5-to-10 year anticipated lifetime.


Yet on April 28, 2022, each instrument’s alignment was completed, with a ~20 year lifetime expected.


Both telescope and team performed dazzlingly, surpassing expectations overall.



First: the pristine, on-course launch conserved fuel purposed for course-correction.


JWST reached its destination, the L2 Lagrange point, ahead of schedule.


Every component deployed correctly, and cooled as planned.


In early February, the 7-step alignment/commissioning process began.



First, the images produced by each mirror segment were identified.




Second, the images were aligned, and then third, were stacked.



Fourth, coarse phasing synthesized 18 small telescopes into one large one.



Fifth, NIRCam’s fine phasing occurred, creating the first fully focused image.



JWST’s unique set of spikes arises from the telescope’s optical design.



Sixth, the alignment coverage extended across JWST’s instrument suite and full field-of-view.



Seventh, final iterative corrections finished the alignment.



Now NIRCam,



fine-guidance sensor,



NIRISS,



NIRSPEC,



and MIRI instruments are all aligned.



Only instrument commissioning and final calibrations remain.



With fuel savings and rapid alignment, ~20+ years of science operations will soon begin.



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