ANDREW LIMBONG, HOST:
Here's what I know about the sun - it's big, it's hot and if I stay out in it too long, my skin starts to peel. But there's so much we don't know about it. And we're going to learn so much more thanks to the Parker Solar Probe. This little spacecraft managed to do something historic this week. It got closer to the sun than any other human-made object. Nour Rawafi is the project scientist for NASA's Parker Solar Probe mission and is with us now. Welcome, Nour.
NOUR RAWAFI: Thank you so much. Thank you for having me.
LIMBONG: All right. So tell me about the Parker Solar Probe. What is its job, and what is it looking for?
RAWAFI: The Parker Solar Probe is a NASA mission that was built at the Johns Hopkins Applied Physics Lab for NASA, and it launched in 2018. And the goal is to get as close as possible to the sun and to help us understand some mysteries about our star. The sun is a magnetized star. It's very active. And it - every now and then, it produces these magnificent explosions, like flares and coronal mass ejections, that drive space weather here on Earth. And Parker Solar Probe will help us to understand all this phenomena and more because we are venturing into a region of space that we never visited before, and every measurement Parker Solar Probe make is a potential discovery.
LIMBONG: And why are these discoveries such a big deal for NASA?
RAWAFI: They are a big deal for many reasons. There are billions and billions of stars out there, and we are wondering if there is life elsewhere in the universe. And to do that, we need to understand how a star interacts with its planetary system, in particular in the habitability zone, like us here on Earth. And the best way to do that is to understand our star, which is our nearest neighbor here, and how it interacts with us here on Earth but also on other places like Europa, like other planets in the solar system.
But more than that, we are actually living in the atmosphere of the sun, that is the solar wind, and whatever the sun does can affect us in many ways. Like, for example, the geostorms (ph) that we saw in May and October of this year that can affect space equipment like telecommunication satellites, like astronauts. So in order to live in harmony with our star, we need to understand how it works. That way, we can predict what it's going to do at any given time and take the right measures to mitigate its effects.
LIMBONG: All right. Let's talk about how you pulled this off. How did NASA manage to get that close and not burn up?
RAWAFI: This is really where the importance and the significance of this milestone comes in. Scientists start thinking about mission like Parker Solar Probe back in 1958. And NASA, since the mid '70s, tried to implement the mission four or five times. All of these attempts did not come to fruition for a simple reason - is that we did not have the technology necessary to fly a spacecraft in a safe manner very close within the atmosphere of the sun. Back in 2001, NASA commissioned the Applied Physics Lab to look into material for a heat shield. It took us about six years to come up with the right material. We knew that we can build it, and it will be the right material for the spacecraft.
And you can't believe it - the heat shield of Parker Solar Probe is basically a piece of carbon foam, but it's a very special one. It's really a very special one. When Parker Solar Probe got very close to the sun, Tuesday of this week, we were - our estimate, it will - the side of the heat shield facing the sun will experience temperatures in order of between 1,800 and 1,900 degrees Fahrenheit.
LIMBONG: It's a little hot.
RAWAFI: Yeah. It's pretty hot.
LIMBONG: Yeah.
RAWAFI: And - but the magic is - I say it's magic. It's engineering - is that a yard behind that, it's almost room temperature, and it's there where the main body of the spacecraft and most of the payload resides. And that's how we achieved the mission. But it took us so long to do it. And now Parker Solar Probe is doing really marvelous job around the sun.
LIMBONG: You know, as I understand it, there was a period during this mission that scientists were not in contact with the probe, right? So you lost contact with it on the 24th, just as it was getting close?
RAWAFI: So on the way in, we got a signal that we call a beacon tone on the 19 of December, saying the spacecraft is nominal. It's ready to go through the flight path (ph). But the following days, including the closest approach, we had absolutely no idea how Parker Solar Probe was doing. We had to wait until Friday, until Parker Solar Probe emerged on the other side, to send us a signal saying, everything is good. Everything is nominal. And just the funny thing is that this time around, Parker Solar Probe sent that signal four times. It's like to tell us, guys, don't be nervous.
LIMBONG: (Laughter) I'm here. I'm here.
RAWAFI: Everything is under control.
LIMBONG: Yeah. What was that waiting period like, when you couldn't hear anything, and then you heard back?
RAWAFI: I think what you feel in the team is really people are very confident that everything will work fine. But for me, personally, the day of when we were getting ready to get the signal on Friday, I was a little bit nervous.
LIMBONG: That's when you started sweating (laughter).
RAWAFI: Well, you know what? As scientists, we are never relaxed.
LIMBONG: (Laughter).
RAWAFI: Now, you know - you know, now that we know that things went well, now we cannot wait for the data to come down, to see what is in it.
LIMBONG: Yeah. So speaking of which, that data is supposed to come pretty soon, right? And so what do you expect...
RAWAFI: Yeah.
LIMBONG: ...To learn?
RAWAFI: We actually - in the third week of January, we'll start getting the science data down. Every three months, we get a new load of data. We - it's - we get a new orbit, and with it, we get a new load of data. So we scientists - it's like we are spoiled children. So every three months, we are jumping into a new load of data that is fresh and everything, and we are trying to look. And honestly, we don't know what to expect in that data. And if you ask me, I'm hopefully - I'm hoping that Parker Solar Probe is going to give us the best present ever. You know, we are at the end of the year. We have Christmas. We have the end of the year. It's the time to give presents, and I hope Parker Solar Probe will give us a great, great gift this time around.
LIMBONG: That's Nour Rawafi, the project scientist for NASA's Parker Solar Probe mission. Nour, thank you so much.
RAWAFI: Thank you so much. It's my pleasure.
(SOUNDBITE OF MUSIC) Transcript provided by NPR, Copyright NPR.
NPR transcripts are created on a rush deadline by an NPR contractor. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.
