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After years of preparation, numerous tests, and an unfortunate number of setbacks, NASA’s James Webb Space Telescope is fully built and assembled. As of October 6, 2020, it has completed its full suite of environmental tests: the last challenging, and potentially blocking, milestone keeping us from a successful launch. (NORTHROP GRUMMAN)

NASA’s James Webb Passes Enormous Test, On Track For October 2021 Launch

It’s last “hard” test is over. Now, we wait for its launch.

Ethan Siegel
Oct 19 · 3 min read

Despite numerous delays, funding crises, and technical challenges, NASA’s James Webb Space Telescope is almost ready.

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The science instruments aboard the ISIM module being lowered and installed into the main assembly of JWST in 2016. These instruments have been complete for nearly a decade, and have passed all of their rigorous tests. They, along with the rest of James Webb, are ready for launch. (NASA/CHRIS GUNN)

Every single component is fully built, assembled, and integrated.

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Engineers conduct a “Center of Curvature” test on NASA’s James Webb Space Telescope in the clean room at NASA’s Goddard Space Flight Center, Greenbelt, Maryland. This test helped ensure there would be no Hubble-like problems on JWST. (NASA / CHRIS GUNN)

Rigorous pre-launch testing can maximize our chances for Webb’s success.

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Following the complete assembly of NASA’s James Webb Space Telescope, testing teams performed a comprehensive systems evaluation which allowed them to confidently assess Webb’s software and electronic performance as a single fully connected vehicle. (NASA/CHRIS GUNN)

The stowed telescope must survive harsh launch conditions without sustaining damage.

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NASA’s James Webb Space Telescope was folded into its pre-launch configuration and transported to a series of specially-designed chambers for acoustic and sine-vibration testing. After weeks of these tests, Webb emerged fully intact and undamaged. (NASA/CHRIS GUNN)

From its spaceborne environment, all components must then properly deploy.

The primary mirror segments must unfold, aligning to within 20 nanometer tolerance.

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The 18 segments of James Webb in the laboratory, after completed assembly and all coatings have been applied. From the zero-gravity environment of space, these individual segments must form a perfect single plane to within a 20 nanometer tolerance. (NASA/CHRIS GUNN)

All 5 sunshield layers must unfurl without catching, ripping, or tearing.

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This James Webb Space Telescope sunshield prototype is a 1/3rd scale model of the real thing, which will be the largest device of its type when James Webb is launched in 2021. This passive cooling system can cool the telescope down below 77 K: the threshold at which nitrogen gas becomes liquid nitrogen. (ALEX EVERS/NORTHROP GRUMMAN)

Earlier testing exposed vulnerabilities that could arise during launch-and-deployment.

During a 2018 environmental test of the spacecraft element, some screws and washers came off of the bus and sunshield: a flaw that required correction. As of the last and final round of vibration and acoustic testing, this problem appears to have been successfully corrected, while no other comparable ones have arisen. (NORTHROP GRUMMAN)

Subsequent structural corrections and improvements were then implemented.

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After a vibration and acoustic test is completed, a “lights out” inspection occurs, as any possible contamination is easier to find in the dark. NASA’s James Webb Space Telescope has been subject to a number of these tests over the past few years, with the telescope passing the final test, concluded in October of 2020, in every way. (NASA / CHRIS GUNN)

On October 6, 2020, NASA and Northrop Grumman successfully completed Webb’s final environmental stress-test.

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NASA’s James Webb Space Telescope sits inside Chamber A at NASA’s Johnson Space Center in Houston after having completed its cryogenic testing on Nov. 18, 2017. This marked the telescope’s final cryogenic testing, and it ensured the observatory is ready for the frigid, airless environment of space. Other tests, like vibration testing, did not go according to plan. (NASA/CHRIS GUNN)

Over several weeks, Webb underwent rigorous trials, experiencing harsher conditions than actual launches.

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Vibration testing of spacecraft, such as NASA’s James Webb, is a necessity to ensure that the spacecraft and all of its components can survive the launch process intact and fully functional. Crewed and uncrewed missions alike must survive this testing, which has been applied to Webb in a number of phases. (NASA / CHRIS GUNN)

It survived high-frequency acoustic pressures, including sounds surpassing 140 decibels.

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Animation of the James Webb Space Telescope atop the pad on which it undergoes a portion of its environmental tests that focus on acoustics and vibrations. These tests are necessary for ensuring that Webb survives its launch and deploys as required. (NASA / NORTHROP GRUMMAN)

Sine-vibration testing shook the spacecraft intensely, exceeding vibrational stresses occurring inside a launching rocket.

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A rocket launch experiences sonic intensity and vibrations that are 100 times greater in intensity and 20 decibels greater in loudness than the loudest seats of all at a rock concert. To simulate a rocket launch, both acoustic and vibrational tests are required. (NASA / ARIANESPACE)

Unlike prior tests, every single component survived, retaining optimal functioning.

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The process of unfurling and tensioning the 5-layer sunshield is one of only a very few tests remaining for NASA’s James Webb Space Telescope to be fully launch-ready. (NASA / JAMES WEBB SPACE TELESCOPE TEAM)

Only sunshield and mirror deployment testing, plus a final systems evaluation, remain as pre-launch milestones.

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One of the last tests that will be performed on NASA’s James Webb is a final check of the mirror deployment sequence in full. With all environmental stress testing now out of the way, these last checks will hopefully be routine, paving the way for a successful 2021 launch. (NASA / JAMES WEBB SPACE TELESCOPE TEAM)

Webb, stowed onboard an Ariane 5, will launch October 2021 from French Guyana.

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This 2017 launch of an Ariane 5 rocket mirrors the launch vehicle of NASA’s James Webb Space Telescope. The Ariane 5 had a string of more than 80 consecutive launch successes before a partial failure a few years ago. It is one of the most reliable launch vehicles in space history. (© ESA-CNES-ARIANESPACE/OPTIQUE VIDÉO DU CSG)

With environmental testing now complete, the Universe awaits.

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As we’re exploring more and more of the Universe, we’re able to look farther away in space, which equates to farther back in time. The James Webb Space Telescope will take us to depths, directly, that our present-day observing facilities cannot match, with Webb’s infrared eyes revealing the ultra-distant starlight that Hubble cannot hope to see. (NASA / JWST AND HST TEAMS)

Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words. Talk less; smile more.

Starts With A Bang is written by Ethan Siegel, Ph.D., author of Beyond The Galaxy, and Treknology: The Science of Star Trek from Tricorders to Warp Drive.

Starts With A Bang!

The Universe is out there, waiting for you to discover it.

Ethan Siegel

Written by

The Universe is: Expanding, cooling, and dark. It starts with a bang! #Cosmology Science writer, astrophysicist, science communicator & NASA columnist.

Starts With A Bang!

The Universe is out there, waiting for you to discover it.

Ethan Siegel

Written by

The Universe is: Expanding, cooling, and dark. It starts with a bang! #Cosmology Science writer, astrophysicist, science communicator & NASA columnist.

Starts With A Bang!

The Universe is out there, waiting for you to discover it.

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