ARI SHAPIRO, HOST:
A long-awaited telescope is finally ready to launch into space. Named after a former NASA administrator, the James Webb Space Telescope is bigger and more powerful than the iconic Hubble Space Telescope. This new telescope has been in the works for decades, and tomorrow morning at 7:20 Eastern time, it's scheduled to blast off. NPR's Joe Palca is here for a preview of tomorrow's launch activities. Hi, Joe.
JOE PALCA, BYLINE: Hi, Ari.
SHAPIRO: Where is this telescope taking off from, and where is it headed?
PALCA: It's taking off from the European Space Agency spaceport in French Guiana. It's launching on an Ariane 5 rocket, and it's the - that's the rocket that's big enough to lift this behemoth of a spacecraft - almost 14,000 pounds.
SHAPIRO: Wow.
PALCA: It's heading for a spot in space about a million miles away. It's a point that has special properties where the Sun and the Earth gravity balance each other out, so it's easy to stay in one place. And it's also a spot that can keep it in touch with NASA ground stations around the clock.
SHAPIRO: And what's it going to be able to do that Hubble can't?
PALCA: Well, a lot. Its main mirror is much bigger than Hubble. It's 21 feet across as opposed to 9 feet across, and the bigger the mirror, the better. You would think of a telescope as a bucket, and light from stars are like raindrops. The bigger the bucket, the more rain you catch, and the bigger the mirror, the more light from distant stars. Webb can see also at different wavelengths from Hubble, and this is a big deal because this telescope is going to tell us things about why the universe looks the way it does. For example, Webb should be able to look at the atmospheres of distant planets and see which ones might be capable of sustaining life. And it'll be able to see things that were just starting to take shape in the early days of the universe. Swara Ravindranath is an astronomer with the Space Telescope Science Institute.
SWARA RAVINDRANATH: Webb will be able to show us the very first galaxies and also the earliest stages of galaxy assembly.
PALCA: That's going to be like seeing baby pictures of the universe soon after everything came into being.
SHAPIRO: Incredible. Some people are going to remember that Hubble had a problem that was discovered soon after its launch. They had to send astronauts to fix it. Are there worries that something similar might happen with Webb?
PALCA: In a word, yes. I think people are really terrified that that's a possibility, and there is no repair mission at this point. There's no way to get astronauts out that far. And a lot of things - a lot of things have to work right. Webb has this giant sunshield about the size of a tennis court that has to unfold. It's there to keep the spacecraft cool. And it's an amazingly complex process to unfold this thing. And even the so-called simple things can mess up. I mean, if the solar panels don't deploy properly, there's no power. If the antenna doesn't lock into position, you can't keep talking to Earth. It's a lot to go wrong.
SHAPIRO: How long is it going to take for the telescope to completely unfold before we know whether it's safe and working?
PALCA: Well, it's about two weeks to deploy. It's the solar array, the antennas I mentioned, the multi-day process of unfurling the sunshield and the mirrors partially folded up - it has to unfold. And it's kind of cool looking. It's not like a telescope in a tube. It's all naked, so you can see all the parts right in front of you. I've seen it on the ground almost fully deployed. When it gets to its - it also has to stop when it gets to its parking place, so essentially the brakes have to work. It's a rocket engine, of course. And then it has to cool down. And it's only then that people will know for sure that it's going to work.
SHAPIRO: I'm starting to understand why this thing is 14,000 pounds. When are we going to see photos if everything goes according to plan?
PALCA: Well, it's a six-month commissioning process, and then the - that's where they test and make sure everything's working properly. And then, yeah, the images should start coming in. And from what they say, it should be eye-popping. I'm looking forward to it.
SHAPIRO: We'll keep our fingers crossed. NPR science correspondent Joe Palca, thanks for the preview.
PALCA: You're welcome.
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