The Webb Telescope Is Counting Down To Liftoff

JOHN DANKOSKY: This is Science Friday. I’m John Dankosky. It’s been over 20 years in the making. First proposed back in the 1990s as the Next Generation Space Telescope, now it’s known as the James Webb Space Telescope, but all the cool kids call it JWST. And if all goes according to plan, it’s set to launch next week from French Guyana. From there, it’s set to take a month-long, million-mile trip to its orbit.

But why are astronomers so excited about it? What’s the goal beyond just a Hubble successor? Joining me now to help us peer into the JWST is Dr. Amber Straughn.

She’s an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and she serves as deputy project scientist for the James Webb Space Telescope Science Communications. And if you watch her TikTok videos, you will know she’s very excited about Webb getting up there. Welcome to Science Friday, Doctor. Thanks for being here.

AMBER STRAUGHN: Thank you. It’s great to be here.

JOHN DANKOSKY: So for those of us who haven’t been following too closely, maybe you could just describe what exactly the Webb is and what the status is right now.

AMBER STRAUGHN: Sure, so you already sort of hinted at it. So JWST is built to be the scientific successor to Hubble. We have designed it to answer some of the biggest questions in astronomy today that Hubble just can’t quite answer. And some of those big questions include things like, what were the first galaxies like? What are the atmospheres of exoplanets like? And we hope to learn more about objects within our own solar system, as well as things like star formation and planet formation. It’s really sort of the whole universe that we hope to learn more about with this awesome new telescope.

JOHN DANKOSKY: As of right now, we’re hoping for a launch sometime late next week, but it’s been delayed again. This has all been a long time coming. Maybe you can talk us through some of the delays, some of the anticipation that you’ve had?

AMBER STRAUGHN: Sure, yeah. So I’ve worked on this telescope project for– sort of formally for about 12 or 13 years at NASA, and informally for a couple of years more. So yeah, it’s been a long road. But you know what? This is the largest, most complex telescope that NASA has ever sent into space. It is groundbreaking, from an engineering sense, in so many different ways. In hindsight, the fact that we have had delays is not really that surprising, because we’re building something that is pushing the edge of what’s possible in an engineering sense.

JOHN DANKOSKY: And, obviously, there are going to be delays. What have these delays been about? I mean, is it something technical having to do with the telescope itself? Is it having something having to do with the launch? What can you tell us about the delays?

AMBER STRAUGHN: Well, this last, most recent delay– a couple of day delay– was the last big thing that happened down at the launch site. Just a few days ago, the telescope was installed onto the rocket, right? That’s a huge, huge deal, huge milestone.

So it’s been installed onto the rocket. And then, the next step in integration would be putting the rocket fairing on the telescope– so like the nose cone of the rocket. We have to install that.

So that’s the next step. But before we can do that, we have to make sure that the spacecraft is communicating with the launch vehicle. And there’s a communications issue right now between the spacecraft and the launch vehicle system. And that’s what the team is working on right now.

JOHN DANKOSKY: And you say it’s strapped to a rocket right now in French Guyana. Explain why it’s there.

AMBER STRAUGHN: Right, so this telescope is an international collaboration between NASA, the European Space Agency, and the Canadian Space Agency. So it’s a worldwide effort. And one of the things that ESA is providing us is the launch vehicle. So we’re launching on an Ariane V rocket, and their launch port is down in French Guyana in South America.

JOHN DANKOSKY: OK, so once it finally launches– hopefully, very soon– it’s still got about a month to go to get to its orbit. Why is it going so far away? What’s special at this particular orbit?

AMBER STRAUGHN: So we’re putting JWST at what’s called the second Lagrange Point. So Lagrange Points are these really cool– it’s kind of a cool gravitational trick that the Sun and the Earth system play. So there ends up being these sort of stable points in the whole Earth-Sun gravity system, and one of them happens to be at this approximately million mile away point called the second Lagrange point, L2. So that point is about a million miles from Earth– about 4 times further away than the Moon, to give you a sense of scale there.

So we can basically put spacecraft there, and they sort of will hang around there, and it will orbit the Sun along with the Earth. So you kind of think of it like the Earth is sort of dragging it along in its orbit. And another way you can think about it is it will sort of always be in the midnight sky. It’s always straight out.

Which, it’s good to put spacecraft there, because we can easily communicate with them. But it was necessary for JWST for it to be very, very cold. The spacecraft has to be super cold. And so that’s why we’re putting it out into deep space.

Now, it has to be cold because it’s an infrared telescope. So whereas Hubble sees the universe primarily in optical, visible light that your eyes see, we’ve designed JWST to see the universe in infrared light. And everything glows in infrared. [LAUGHS] And spacecraft glow, too.

And so since we’re trying to detect faint infrared signals from the distant universe, our spacecraft has to be very, very cold so it’s not sort of glowing and seeing itself. So that’s why we’re putting it out into deep space.

JOHN DANKOSKY: That’s very cool. So a completely different technology. I mean, when you talked about this being the successor to the Hubble, you’re not talking about Hubble 2.0– just a better type of Hubble. This is an entirely different technology that’s going to allow you to see in a different way.

AMBER STRAUGHN: Absolutely, yes. It’s a successor to Hubble really only in a scientific sense. From an engineering sense, it is completely different. I mean, if you go look at pictures of the telescope, you’ll see it doesn’t look like what we normally conceptualize as a telescope.

So yeah, it’s very different in that sense, in the sense that it will observe infrared light instead of visible light. It’s also huge. It is– the mirror is about 6 times bigger than Hubble’s mirror, and it has a sun shield about the size of a tennis court. It stands over 3 stories tall. So it is way, way bigger than Hubble. And, of course, its detectors are more advanced and all of that. And so you sort of combine all of those things together, it gives us a telescope that will be, we think, about 100 times more powerful than Hubble, all together.

JOHN DANKOSKY: You described it a little bit, but there’s a kind of a honeycomb-like hexagonal design of the telescope. Why does it look like that?

AMBER STRAUGHN: Yeah, so this also goes back to the fact that it’s just so big. It’s a huge telescope. The mirror is about 6 and 1/2 meters across– about 21 and 1/2 feet across– and that is bigger than any rocket that we have to put it in fully deployed. So we have to fold the entire telescope up– the mirror and this tennis court-size sun shield. We have to fold it all up in order to fit into the rocket, and then it unfolds in space.

And the reason we chose the hexagons is because you can sort of efficiently pack hexagons together. And then, we can, again, fold– there are three mirrors on the sides that we fold backwards to get it stowed inside the rocket. And then, they’ll deploy– unfold– once they’re in space.

JOHN DANKOSKY: Very cool. So you were talking about what you’re going to be able to see with this, and maybe we can talk through that a little bit. First of all, just to give us an understanding, we’ve seen the amazing images that have come from Hubble. If you aimed this at some of the same targets we’ve already seen Hubble pictures of, how would it be different? Would it just be higher resolution? What would be different?

AMBER STRAUGHN: The pictures will look different, because they will be infrared. And sort of a related question I often get is, will they be pretty? [LAUGHS] Because Hubble images are, obviously, stunningly beautiful. And the answer is, absolutely, yes. They will be gorgeous beautiful images.

Hubble, people often think of the Pillars of Creation, the Eagle Nebula. And Hubble has a teeny little bit of capability in the near-infrared. And so if you go look at the near-infrared image from Hubble of the Pillars of Creation, you’ll get a teeny little hint of what the images from JWST will look like, only much, much better.

Of course, we have Spitzer Space Telescope, which also observed in the infrared. Much smaller– Spitzer is a much smaller telescope. So we have some examples of what infrared images look like, and they will be beautiful. But this telescope, again, since it’s so big, the images will be much higher resolution than the infrared images that we’ve seen before.

JOHN DANKOSKY: So higher resolution, but what else will this be able to do that previous telescopes haven’t been able to do? If you’re describing just the very coolest thing about this telescope, what do you tell people?

AMBER STRAUGHN: Well, I mean, oh, there are so many cool things.

JOHN DANKOSKY: [LAUGHS]

AMBER STRAUGHN: But to get down to the science, this telescope was designed– very early on, the primary science driver for the telescope was to be able to detect those first galaxies that were born after the Big Bang. So we’re talking about looking back in time over 13 and 1/2 billion years into the past to see the very first galaxies light up in the early universe. So that’s a part of space that we’ve never seen at all.

You know, Hubble has been able to look back into pretty distant space to see some pretty distant galaxies, but we know that the furthest we’ve seen with Hubble, we know those aren’t the first galaxies that were born. And so we know that in order to see those first galaxies, we have to use infrared light. So the light from those galaxies– the galaxies are so far away, the expansion of space-time has caused their light to be redshifted all the way into the infrared part of the spectrum, and so we have to have an infrared telescope to detect them. So that’s one example of I think groundbreaking science that we’ll be able to learn from this telescope, because that’s how the universe got started, is the first galaxies. And we don’t know anything about them.

JOHN DANKOSKY: Of course, the beginning of the universe is something that all scientists– and probably all people– should be really interested in. But I’m going to guess that the thing that most laypeople will be most excited about is exoplanet research. I mean, we always are thinking about what are the other planets that might be like Earth? So why is this particular telescope going to be better than the others we have for searching out life elsewhere, or planets elsewhere?

AMBER STRAUGHN: Yeah, so when we first start, when we– this was before I was an astronomer, but when astronomers first started conceptualizing this new telescope, started thinking about it even before Hubble was launched, so at that time, we didn’t even know about exoplanets. Or, we thought they were there, but we certainly didn’t know what we knew today, which is that exoplanets are everywhere.

And so it just so happens we got lucky, in a way, that a lot of the really interesting chemical signatures in exoplanet atmospheres happen to be in the infrared part of the spectrum. So things like water vapor, and carbon dioxide, and methane– you know, all those things that we think about being the building blocks to life– all of those are in the infrared part of the spectrum. And so JWST is going to revolutionize, I think, our study of exoplanets.

So my own area of research is galaxy evolution. I’m interested in how galaxies change over time, how they form their stars, and black holes. And so exoplanets is pretty far from my own area of research, but I think that the exoplanet science that JWST is going to be able to do it’s going to be some of the most impressive, some of the coolest stuff.

JOHN DANKOSKY: So the Hubble was a notoriously known for being a bit blurry when it was first launched, and that certainly had an awful lot of scientists scared. How soon after this launch will you know whether or not everything’s fine, everything’s OK and working properly?

AMBER STRAUGHN: Well, we do have a very long commissioning period, relatively speaking. So once we launch the telescope, it takes about two weeks to unfold. So that whole intricate, complicated deployment process takes two weeks. And then, it’s a couple more weeks to get out to that million-mile point, L2. And then, we have about five more months of what we call commissioning, of bringing the telescope up to working order.

So that includes things like, first of all, just letting the telescope cool down. So it doesn’t cool instantly. It takes a while for it to cool.

And then, we have four science instruments on board that we have to bring up to working order one at a time. And then, that process of getting the mirrors aligned takes several months. So every individual mirror segment– all 18 mirror segments– have an individual motor on the back where we can move it and tweak each mirror. And so we’ll spend several months taking an image of a single star and then tweaking the mirror to make sure all the mirrors line up.

So we’re fairly certain we’re not going to have a Hubble problem, because we can fix the mirrors in real time in space. And that’s part of the commissioning process.

JOHN DANKOSKY: This is Science Friday from WNYC Studios. I’m talking with Dr. Amber Straughn. She’s an astrophysicist. She’s at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. And she’s part of the big launch of the James Webb Space Telescope, which we’re talking about.

It’s coming up very soon. Given the excitement around this, I can only imagine there are just a lot of scientists who are waiting to use this. How do you even decide who gets time on this telescope?

AMBER STRAUGHN: So it’s actually a pretty cool process, because it’s sort of a democratic process. So anyone in the world that has a great idea can write a proposal to use the telescope. And this is how it works with Hubble, too.

So once a year, astronomers from around the world write their proposals. And then, they submit those proposals. And then, another team of astronomers gets together– and this is actually all anonymized as of just the last few years. Other astronomers get together and review them and select which ones they think are going to be great. And that’s how we decide who gets to use the telescope. So it’s anyone can compete for time.

JOHN DANKOSKY: That’s really cool. So I don’t know, Hubble’s been in the sky for 30 years now. How long is Webb supposed to operate?

AMBER STRAUGHN: So we have a minimum mission lifetime requirement of 5 and 1/2 years, but we fully expect it to last 10 years, maybe longer. Our life-limiting factor is fuel. So when we’re out at that L2 point– so L2 is actually a semi-stable point, so we have to use fuel to keep the telescope in an orbit around L2. So we use fuel for that. And when we run out of fuel, that’s when the mission will end.

And if we get a super-efficient launch, we could last more than 10 years. 12, 15 who knows? It all sort of depends on the fuel situation. But we fully expect 10 years.

JOHN DANKOSKY: I just have to ask you before I let you go, I mean, your job is looking so incredibly far into the past using these telescopes. Is it ever hard for you, as just a human with our own limitations, to wait for this work to come to its fruition? Because you’ve been working at this for such a long time. You’ve got to wait for the next telescope to go up to do more of your work. That’s got to be a little, I don’t know, frustrating.

AMBER STRAUGHN: Well, yeah. I guess us astronomers would always love it if we could launch a huge telescope every few years. That would be great. [LAUGHS] But that’s not our situation, and that’s OK.

And I mean, technology development takes a lot of time. The technology that we use in these telescopes really is– if it was easy to do, we would be doing it a lot faster. But yeah, the waiting does get a little tiresome. But you know what? It’s going to be worth it. It’s going to be worth the wait.

JOHN DANKOSKY: Dr. Amber Straughn is an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. She serves as deputy project scientist for the James Webb Space Telescope Science Communications. Thanks so much for talking with me today. Good luck with this upcoming launch.

AMBER STRAUGHN: Thank you so much. Very excited about it.

JOHN DANKOSKY: Yeah, you can watch the TikTok videos. As I said, she’s very excited about it.

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