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Narrator: NASA's Parker Solar Probe is a mission to explore the Sun. How can it do that?

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Why won’t the spacecraft melt? Excellent questions. 

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You can’t face off with the sun without packing the right gear. 

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This is why Solar Probe is equipped with a white shield that reflects heat off the front and keeps things cool in the back.

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Betsy Congdon: The heat shield is made of a couple of different materials. 

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One is of carbon carbon which is a lot like the graphite epoxy 

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you might see in your golf clubs or tennis rackets, but it’s been super heated. 

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The inside is a carbon foam which is another form of carbon which

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is about 97% air. It's a very light weight way of making

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a very strong structure.

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Narrator: Nobody likes a needy explorer. Solar Probe can take care of itself, thank you very much, 

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and that’s because it has autonomy software that will keep its instruments safe and cool behind the heat shield.

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We are too far away to joystick it into place,

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so it basically has to always be sensing whether

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or not the heat shield is in the right position and correct itself 

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if it isn’t. There are these things called solar limb sensors, 

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just poking out at the very edge of the shadow. If those get illuminated, 

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the spacecraft knows, “Oh, I’m going the wrong direction,” and can actually right itself. 

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Narrator: It’s important to stay hydrated in the Sun, even for a spacecraft! 

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Solar Probe circulates water to keep the solar cells 

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from overheating. It stays cool and keeps power.

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Betsy: Basically water flows behind the solar arrays and into the radiators, 

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so the water warms up behind the solar cells and then cools 

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down at the radiator that heat transfer is happening a lot like 

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the veins in your body 

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Narrator: Yes, you read right: Heat is not the same as temperature. Temperature is a measurement, but heat is an energy transfer.

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This matters because Solar Probe will be 

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visiting the sun’s outer layer, the corona. Like all stars, 

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the Sun is made of plasma. How tightly packed that plasma is 

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depends on the layer. While the Sun’s corona has a very high temperature

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the plasma particles are fairly spread out, so even though the temperature 

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in the corona is 1,000,000 Fahrenheit,

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the heat around the spacecraft is manageable. 

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Betsy: The corona and where we are going is actually not that dense at all, there’s only a couple particles. 

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Those are very hot, but we aren’t touching a lot of them. 

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So, it’s kind of like when you put your hand into an oven. The oven might be at 400 degrees Fahrenheit, 

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but your hand isn’t going to be at 400 degrees Fahrenheit. 

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Narrator: Thanks to its design and destination, this cool, confident spacecraft is all set to explore. 

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We can just sit back and chill, as Parker Solar Probe takes the heat.

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