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NASA has successfully deployed the sunshield on the James Webb Space Telescope


Over the last 10 days, the most nerve-wracking activity for NASA has been the unfolding of the James Webb Space Telescope. The telescope had to be folded up origami-style to fit on the rocket that launched it into space. Once operational, the telescope will provide unprecedented views of the universe. There's more to do, but today, mission managers successfully completed the most complicated part of the unfolding process. To bring us up to date is NPR science correspondent Joe Palca. And, Joe, what exactly did....


CORNISH: Hey. How are you?

PALCA: Good. Sorry.

CORNISH: Tell us what mission managers had to do today that made it so complicated.

PALCA: Well, today was the sunshield. And in order to make the measurements it was designed for, the detectors on the space telescope - JWST, as people call it - have to be cooled to about 400 degrees below zero Fahrenheit. To do that, it needs to protect - be protected from the sun, and hence the sunshield. The sunshield itself is made up of five separate thin membranes that are designed to sit one above the other.

And the whole thing is huge - I mean, the size of a tennis court. And it had to be folded up into two small boxes and then unfurled, and each layer had to be tensioned so it would lie flat. Well, the tensioning involved hundreds of cables, pulleys, motors and the like, so it was a complex and slow process.

I listened for an hour as the final layer was tensioned, and it was like listening to paint dry. Every so often, sunshield deployments lead Hillary Stock would come on the control room intercom to call for the next step in the process. And then finally, right around noon...


HILARY STOCK: I can confirm the final latch signature on the aft NTS, which indicates that all five layers of the sunshield are fully tensioned.

CORNISH: OK. She sounds relieved. You called it watching paint drying (laughter). What happened next?

PALCA: Well first, the boss got on the intercom. Bill Ochs is project manager for JWST.


BILL OCHS: This is a really big moment. I just want to congratulate the entire team. Still got a lot of work to do, but getting this sunshield out and deployed is really, really big.

PALCA: And then JWST mission operations manager Carl Starr told everyone it was time to go back to work.


CARL STARR: We got to jump back into the cast here and continue with the coolest thing in space. There is nothing cooler in space than JWST. That's a fact.

PALCA: So get it? Sunshield, cooling - little aerospace humor there.

CORNISH: Got it - NASA jokes. So Bill Ochs, the project manager, said there's still a lot of work to do. What's next for the Webb telescope?

PALCA: Well, the next thing is to adjust the structure that holds the secondary mirror in place. Then, the main mirror has to unfold. That consists of 18 hexagonal mirrors made of beryllium coated in gold. There are 12 segments in the middle that are all set, but there are six more on either side on what they call wings that have to lock into place. And when it's all done, you'll have what amounts to one really huge mirror 21 feet across.

CORNISH: And with that mirror, what's the goal?

PALCA: Well, this is an infrared telescope. And it turns out that the very first stars and galaxies to form are hurdling away from Earth so fast that the light is shifted from visible wavelengths into the infrared. So the Hubble Telescope couldn't see that light, but JWST can. So there'll be unprecedented views of the early universe. And another thing the telescope's going to be able to do is study the atmospheres of planets orbiting stars outside our solar system, some of which might have atmospheres hospitable for life.

CORNISH: That's NPR's Joe Palca. Thanks for your reporting.

PALCA: You're welcome.


Joe Palca is a science correspondent for NPR. Since joining NPR in 1992, Palca has covered a range of science topics — everything from biomedical research to astronomy. He is currently focused on the eponymous series, "Joe's Big Idea." Stories in the series explore the minds and motivations of scientists and inventors. Palca is also the founder of NPR Scicommers – A science communication collective.