James Webb Space Telescope completes risky sunshield deployment

Shawn Knight

Posts: 14,149   +154
Staff member
In brief: The James Webb Space Telescope has successfully deployed its five-layer, 70-foot sunshield, checking off a critical make-or-break step in the observatory’s multi-phase, post-launch prep as it continues its journey towards the L2 insertion point.

The unfolding and tensioning of the sunshield took place over the course of eight days, involving 139 of Webb’s 178 release mechanisms as well as 70 hinge assemblies, eight deployment motors, 90 individual cables and roughly 400 pulleys.

If that sounds daunting, consider this: the James Webb Space Telescope has 344 so-called single point failures, or individual steps that must work without incident. If any one point fails – a cable gets stuck or a release mechanism doesn’t trigger – the whole project could be in jeopardy.

The sunshield will protect the telescope from light and heat from the Sun, Earth and Moon. Each layer is about as thin as a human hair, but collectively, they'll be able to reduce exposure from the Sun from more than 200 kilowatts of solar energy down to just a fraction of a watt. That'll be crucial in keeping the scope nice and chilly for optimal operation.

Things have been going swimmingly thus far, but Webb isn’t out of the woods yet. It’ll be another five-and-a-half months before the observatory delivers its first images. Between now and then, Webb must deploy its secondary mirror and primary mirror wings, calibrate its science instruments and align its telescope optics.

Interested parties can follow the telescope's journey through space over on NASA’s website. As of this writing, Webb is approximately 593,000 miles from Earth and has another 305,000 miles to travel before it reaches its target orbit. Deployment of the secondary mirror begins today.

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wiyosaya

Posts: 7,706   +6,654
Great - hope the good news for James Webb keeps coming as I‘m so much looking forward to the first images and what we can learn from them.
Agreed. Maybe, if all goes well and JWST finally comes on line, all of the "costs too much" crowd will see things differently and stop complaining.

Or is that too much to hope for? 🤷‍♂️
 

yRaz

Posts: 4,435   +5,207
Agreed. Maybe, if all goes well and JWST finally comes on line, all of the "costs too much" crowd will see things differently and stop complaining.

Or is that too much to hope for? 🤷‍♂️
Too much to hope for. 10 billion over 20 years. 500 million a year is only about 0.03% of the US spending budget. Also, we aren't the only ones paying for it. Canada and the EU also have contributed a decent chunk of change to it.
 

wiyosaya

Posts: 7,706   +6,654
Too much to hope for. 10 billion over 20 years. 500 million a year is only about 0.03% of the US spending budget. Also, we aren't the only ones paying for it. Canada and the EU also have contributed a decent chunk of change to it.
Yes. Agreed. The EU also footed the bill for the Ariane 5 it rode to space.

And more good news, the Secondary Mirror Deployment was successfully completed today. https://jwst.nasa.gov/content/webbLaunch/whereIsWebb.html?units=metric
 

wiyosaya

Posts: 7,706   +6,654
For anyone interested, there's a site/pdf that explains some of the benefits of technology invented for the JWST that are already being used here on Earth in wide-ranging applications.


Webb is rolling along with most major deployments done. Tomorrow, if everything goes well, everything else that had to be specially packed to launch Webb, will be deployed and Webb will be fully deployed with only the last remaining milestone being its insertion into orbit at the L2 point.
 

captaincranky

Posts: 18,745   +7,683
Wtf is a "mile"? A unit of distance equal to the height of someone called Miles?
You're just mad because they didn't name 5,280 feet after you.

To borrow your acronym, "WTF" does your question have to do with this topic?

EDIT: since the "mile" was derived in Roman times, the guys name was probably "Milius", or "Milian", anyway.