Webb telescope successfully passes critical test

The Webb telescope team reported that a major step had been successfully completed on schedule. The telescope was launched on December 24th and all its components had to be folded into a small space to fit into the rocket nose cone and then opened up once it was in space, After seven days, the schedule called for the five-layered tennis court-sized silvery heat shield to be opened up and it did so.

The shiny silver shield measures 69.5 feet long by 46.5 feet wide (21.2 by 14.2 meters) when fully deployed — far too large to fit inside the protective payload fairing of any currently operational rocket. So it was designed to launch in a highly compact configuration and then unfold once Webb got to space.

That deployment is an elaborate, multistep process with many different potential failure points that could sink the entire mission.

“Webb’s sunshield assembly includes 140 release mechanisms, approximately 70 hinge assemblies, eight deployment motors, bearings, springs, gears, about 400 pulleys and 90 cables totaling 1,312 feet [400 m],” Webb spacecraft systems engineer Krystal Puga, who works at Northrop Grumman, the prime contractor for the mission, said in a video about Webb’s deployments that NASA posted in October.

Over the next six days, the rest of the telescope will get unfolded, starting in three days with the deployment of the secondary mirror support structure. And then it heads to its destination, the second Lagrange point which it should reach after 29 days.

You can see the sequence of steps in this short video.

It is a truly remarkable piece of engineering.


  1. Matt G says

    I’m so nervous about this whole procedure I can’t imagine how those who have poured their lives into this project must feel. Go, Webb, go!

  2. says

    I worked a menial job at Space Telescope Science Institute as an undergrad (typing in guide star data in the VAX) and when the Hubble was found to have the mirror aberration the whole place was pure gloom. Everyone was walking around as if they had lost a child.

    I’m so happy that the JWST appears to be doing well. Now that the heat shield is deployed they ought to be into operations that are important but retryable -- if such and such doesn’t fully lock they can back it off and try again. In one of the heat shield tests it ripped a corner, which would (if it happened now) result in loss of the vehicle and there’s no space shuttle and nothing that can fly out to fix it. It’s a total buttpucker.

  3. Holms says

    Very good, though I was sad to learn that the first actual astronomy to be conducted with it will not take place until after the instruments had been cooled and calibrated, taking up to six months to do so.

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