James Webb Space Telescope Wings It
IRA FLATOW, HOST:
Up next, the Hubble Space Telescope. It has dazzled us for years with photos it beams back from space, not to mention all the scientific data. But Hubble's getting on in years. It's been up there, believe it or not, almost 23 years. When we first came on SCIENCE FRIDAY - we're in our 22nd year - we were just starting to talk about Hubble Space Telescope.
Waiting in the wings now is the new kid on the block, the James Webb Space Telescope that is set to launch in 2018. And the skeleton of this tennis court-sized telescope is being pieced together right now, as we speak, here in Utah. Think world's biggest Erector Set, built to survive temperatures of minus 400 degrees Fahrenheit. That's a little bit chilly.
Considering how much more advanced today's technology is, how will the James Webb improve on the Hubble, and what questions do astronomers want to solve with it? That's what we're going to be talking about now.
Bob Hellekson is the ATK program manager for NASA's James Webb Space Telescope. ATK's Aerospace Group is headquartered in Magna, Utah, just west of Salt Lake. Welcome to SCIENCE FRIDAY.
BOB HELLEKSON: Thank you very much, Ira.
FLATOW: You're welcome. Stacy Palen is director of the Ott Planetarium and professor of physics at Weber State University in Ogden, Utah. Welcome to SCIENCE FRIDAY, Dr. Palen.
DR. STACY PALEN: Thank you.
FLATOW: Let me ask you, Dr. Palen, what - why do we need a new telescope? What would you like to learn with a new telescope?
PALEN: Well, there are sort of two things going on there. One is that, as you say, Hubble Space Telescope is aging, and telescopes don't last forever. So sooner or later, you need a new one. James Webb is optimized in infrared instead of in the visible. And so it will be able to see things that Hubble Space Telescope was not necessarily designed, as its primary mission, to see.
For example, James Webb is going to go after the first stars in the earliest galaxies ever to form in the universe. And it's also going to go after dusty places - so places where planets are forming, places where stars are forming and places where stars are dying. All of that is going to be accessible with James Webb in a way that it's not with Hubble.
FLATOW: Could we see some of these cooler exoplanets, things like that?
PALEN: And especially places where exoplanets are forming, and that might help us figure out what's going on in those very early stages when we've got lots and lots of planets roaming around inside a solar system like a giant pool table, and they're knocking each other all over the place. And maybe we can figure out a little bit more about what's going on there.
FLATOW: Bob, can you describe first, give us an audible picture of what it looks like, the telescope, and how you're building it?
HELLEKSON: Yeah. Certainly, Ira. The astronomers want a larger primary mirror, and that leads to better science. So the James Webb Space Telescope primary mirror is on order of about 21 feet in diameter, where the Hubble Space Telescope had about an eight foot diameter. So we're talking about a primary mirror area that's over 700 percent larger than Hubble.
The telescope itself does not have a barrel like Hubble did, but instead it's protected by a very large sunshield, and that sunshield is, what you mentioned, about the size of a tennis court. So we have a tennis court in - at the base of the telescope, and then the telescope on top is more than 21 feet in diameter and leads to about a three-story telescope overall.
FLATOW: I'm Ira Flatow. This is SCIENCE FRIDAY from NPR, talking about the new James Webb Scope.
And you had - this has to be operated in the shadow. There was a special place found in orbit. It's like four times further away than the moon is. It's like a million miles away. But it has to be orbiting in both the shadow of the Earth and the moon at the same time.
HELLEKSON: Yeah. The right point for this telescope was the Lagrange point 2. It's about a million miles away from Earth, and that's - rotates around the sun with the Earth. So they try to keep it in the shadow of the Earth as much as possible. As Stacy mentioned, they're looking for basically infrared heat. So to be in the coldest part of deep space is a better location for this observatory.
FLATOW: So you have to keep it at like minus 400 degrees Fahrenheit.
HELLEKSON: The bottom side of that sunshield is going to be about as warm as what Hubble is or ambient temperatures, but on the cold side, yes, it's minus 400 degrees. That's better for the science, and it's the environment the - that the astronomers want that telescope in.
FLATOW: Wow. And engineering challenges to build this thing must have been enormous.
HELLEKSON: We're building it out of graphite composite materials here at ATK. Not only we're doing the engineering, the manufacturing, as well as testing and measuring that we're going to achieve the chief requirement that ATK had, which was holding that telescope extremely steady, and the steady description of the requirement was in nanometers. We're going to hold this telescope within 38 nanometers - or about one one-thousandth the thickness of a human hair - while it's taking its instrument observations.
FLATOW: Glad you're doing it and not me. Let's go up to the balcony for a question. Yeah.
AUDIENCE MEMBER: Thanks. How big would a telescope need to be to look at Kepler-62e and F, the exoplanets that were found last week?
FLATOW: Dr. Palen?
PALEN: ...it's almost not a question of how big the telescope needs to be, but whether or not it has the right equipment to block out the light from the star. So when you look at one of these objects in space, what you're often seeing together is you're seeing the star and the planets right next to it.
And in order to see only the planets all by itself, you have to be able to, in a way, slide your finger - like I'm doing, right now, to see you - in front of the light so that you can see the planets themselves. And so it's not a limitation of the size of the telescope necessarily, but the equipment that you have on it.
FLATOW: Mm-hmm. Are we going to be able to send back pretty pictures like we did on the Hubble, the, you know...?
PALEN: Absolutely we are.
FLATOW: We are? We are?
PALEN: Yeah, yeah.
FLATOW: People love that. I think that's NASA's biggest selling point, are those photos coming from the Hubble.
PALEN: Oh, they've been fantastic PR for astronomy. Absolutely.
FLATOW: But Webb being in infrared, it's not going to be the same color of pictures.
PALEN: So what we do is we put different filters on that allow through light at different parts of the infrared, and then we color them red, green and blue, so we can make those pictures every bit as lovely. And we have to color them because we're going to portray different information. We might be portraying information about different temperature ranges or we might be portraying information about different composition areas. But those images wind up incredibly beautiful. And the reason that the Hubble Space Telescope images were so staggeringly beautiful when we saw them was because the resolution of the telescope was so high, it was giving us incredible amounts of detail. And James Webb, because it's a larger telescope, is going to give us even more detail.
FLATOW: Just in time for our big screen TVs. To be able to see...
FLATOW: ...that detail on it. We're going to take a great everybody. Stay at the mics, we'll come back and take your questions and talk them with Bob Hellekson who's the ATK program manager for the Webb Space Telescope. Stacy Palen, director of the Ott Planetarium, professor of physics at the Weber State University. Stay with us. We'll be right back after this break.
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FLATOW: This is SCIENCE FRIDAY. I'm Ira Flatow. We're talking this hour about the James Webb Telescope with Bob Hellekson of ATK; and Stacy Palen of the Ott Planetarium, professor of physics at the Weber State University. We're here in Salt Lake City. Let's - lot of people want to talk. Let's see how many we can get it. Yes, sir.
MEMBER: I'm wondering how you are able to focus the mirrors on these telescopes, presumably the material that make them off will contract as you get them to colder temperatures in outer space.
HELLEKSON: OK. Great question. The Hubble was - had a mirror that was basically glass material. The James Webb telescope will have beryllium mirrors, and there's actually 18 segmented mirrors because it's so large that - to fit in a rocket. Each of these segments then have actuators behind them so it will be able to be focused, if you will, once it reaches the Lagrange point.
FLATOW: And because this is so far away, it's not in low earth orbit like the Hubble was. If there's something wrong with this telescope like there was with the Hubble, there's no repair missions.
HELLEKSON: Yeah. That's correct. It's being a million miles away. The Hubble was only about 350 miles away and we could send astronaut to that. But at a million miles away, we can't send astronauts. So it will be checked completely here on earth down at the Houston space center - in the Johnson Space Center in Houston, Texas.
FLATOW: OK. Let's go right to the microphone here. Oh, a little encouragement here? No. OK. All right. Next one. Yes.
MEMBER: How are the telescopes powered?
FLATOW: It's basic question. We didn't ask that question.
HELLEKSON: Basically, all telescopes are powered with first, solar ray panels that recharge batteries, that supply power throughout the entire telescope. So same thing with the James Webb space telescope, we use that kind of technology that has been used on satellites for a long time.
FLATOW: All right. Solar. Do you have another follow-up to that?
MEMBER: Are there any other power sources you could use if it's too far away from the sun?
HELLEKSON: That's a very good question. Let's see.
HELLEKSON: We don't have a warp drive, but I think we're going to be working on that next. There are other compressed gases and things that are stored on a satellite and can be used for different types of maneuvering. But generally speaking, all of our satellites use the power from the sun to recharge the batteries first.
FLATOW: Dr. Palen, do you want to jump in?
PALEN: Yeah. I'd like to jump in. So some of the rovers that we've sent to Mars have had RTGs on them, and those are radioactive thermal generators. And so just by putting a pile of a radioactive material together, it gets hot and then you can use that energy that's coming off that material to drive a current, and then you can use it to power your electronics. So that's an option that we might have if we wanted to take telescopes and put them very far.
FLATOW: Way out.
PALEN: Way out there.
FLATOW: Way out. But here it's up close to the sun, you make use of solar panels.
PALEN: Well, if you've got it then it's free. Go ahead. Yeah.
FLATOW: I'm not arguing. I'm not arguing.
FLATOW: OK. Yes, sir. Over here. And then we'll go up there.
MEMBER: Um. So how much galaxies will the telescope see? Probably.
FLATOW: Yeah. Tell us how far back. How far away?
FLATOW: Cause you go back in time, right...
FLATOW: ...the further away, further back in time you go.
PALEN: Yeah. So the more distant the galaxies are, the longer it has taken for the light to get to us. And there's actually a limit to how far we can go and that limit -the universe is about 13.8 billion years old, and we can't quite get that far. And the reason we can't quite get that far is because about 300,000 years after that, the universe became transparent for the first time. So we can see all the way back to that. It's called the last scattering surface, which is where the light that was moving around in a fog before that, suddenly is free to move through the universe. And we don't quite know yet, how close to that boundary the first stars and the first galaxies formed. We think it was pretty soon but we're not quite sure exactly when. So that's part of what James Webb is trying to figure, is exactly where did that - when did that start happening.
FLATOW: And so how far back did - ultimate, did you think we can go?
PALEN: I won't be surprised to start - so I'm trying to translate in my head, in red shifts as I'm on the fly. But I think I won't be surprised to see us going back as far as maybe 12 billion years.
FLATOW: Twelve billion years ago. Wow. OK. Yes, sir.
MEMBER: So there's all this talk about old galaxies and the beginnings of the universe, but when's anyone actually going to be looking where the universe is expanding, the new universe?
FLATOW: Yeah. Can you see the dark energy that's expanding? Can we see that or figure that out from the Webb?
PALEN: So, yeah. By studying these very, very old galaxies and the ones in between, we're going to really be able to nail down that acceleration curve and see how the universe is accelerating now. But if you want to see the absolutely most recent, newest part of the universe, there is absolutely, right now, the latest thing. It's right here.
FLORA LITCHMAN, BYLINE: I got it, I got it.
FLATOW: That was a second ago. Yeah.
PALEN: Newer now, now it's even newer.
FLATOW: Now it's - newer, better. Yes, sir
AUDIENCE MEMBER: In many ways Hubble revolutionized our understanding of astronomy in the universe. James Webb will do the same, right? So what do you anticipate as the most exciting thing that comes from James Webb once it's launched?
HELLEKSON: Hmm. Let's see. Let me start with - I think they went back to the Hubble with its original goals and made comparison of what they actually came up with. And the actual inventions were so much far - farther beyond what they ever envisioned, that we're all kind of anticipating the same sort of thing to happen with James Webb. So we're going to look back to the beginning of time, but I'm hoping the dark energy and the dark matter are what we really learn more about besides the stated goals. Now, Stacy, maybe you could add to that.
PALEN: Yeah. And I would say that every astronomer is going to have their favorite thing that they're going to learn something about from James Webb. And I, for example, love to study dying stars and I'll find out things about that. But I think that Bob is right on and one of the great things about these discovery machines is that you think you know what its capabilities are, and you think you know what it's going to see. But when it comes right down to it, we've never looked at the universe at this resolution in the infrared before, and we've never had this quality of data before. And we've never been able to look at this level of detail.
And so I think the surprises are going to be fabulous as we start to open the window that's always been closed.
FLATOW: But there are some astronomers who have been critical about the infrared, that it's just an infrared telescope and it...
FLATOW: Tell us why they're upset with that idea.
PALEN: So James Webb has been billed as the replacement for Hubble, that it's going to take Hubble's place. But it's really not optimized in the optical. It does go a little way into the far red.
HELLEKSON: In other words, the visible part of it.
PALEN: Right. But the part that you can see with your eye, and where Hubble has had such a huge impact is in bringing us these great visible images. And so a lot of astronomers have been upset that James Webb sort of doesn't go into the visible and also has been billed as a replacement for Hubble. And so they're upset about that, that we might be missing this. And one of the reasons for that is that once Hubble comes down, we'll be blind from space in the visible. We won't have any telescopes that even begin to compare.
And one of the most valuable things you can do in astronomy is compare at different wavelengths. So compare the visible to the infrared, to the gamma ray, to the x-ray and compare all those different pictures of the same object, and we won't be able to do that with...
FLATOW: We need two of them.
PALEN: Well, yeah.
HELLEKSON: That'd be a great thing.
FLATOW: We need two.
HELLEKSON: That'd be a great thing.
FLATOW: Right? We got to get another one up there.
PALEN: Or two cameras on the same telescope if you're going to go to all that trouble.
FLATOW: OK. (Unintelligible) camera camera...
FLATOW: OK. Let's go - in the meantime, while we dream about that one...
MEMBER: Hi. I was just curious how the telescopes themselves maintain themselves in space, like if there's any kind of cleaning?
FLATOW: Yeah, good question. Maintenance. (Unintelligible)
HELLEKSON: Oh, yeah.
FLATOW: Can you get a windshield wiper on there?
HELLEKSON: Again, its a million miles away, and we can't really go there to service it like we did the Hubble. This telescope has a bunch of features built in so it's useable life is going to be between five and 10 years. And those micro-meteor kinds of degradations are built in to the design, so we won't need to self-maintenance it. It should be good on it's own for up to 10 years at least.
FLATOW: When you say it's got - so it's equipped to handle these speeding tiny meteorites that might hit it?
HELLEKSON: The design allows for that through it's lifetime of about 10 years. Yes.
FLATOW: So it might look like a little Swiss cheesy but it would still work.
HELLEKSON: That's exactly right.
FLATOW: After a while. And when is it going to be launched? And when will it become operational?
HELLEKSON: Yeah. The NASA community is working to a launch date 0f 2018 and it's going to take about six months to get to it's final position and actually cool down to the place where the temperature - where the instruments can start to be used. So not too long after launch.
FLATOW: All right. Then we're looking forward to it. Thank you both for taking time to be with us today.
HELLEKSON: Thank you very much.
PALEN: Thank you.
FLATOW: Bob Hellerkson is the ATK Program Manager for the Webb space telescope. Stacy Palen, director of the Ott Planetarium and professor of physics at the Weber State University in Ogden, Utah.
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