NASA’s Parker Solar Probe is a mission to explore the Sun.
How can it do that? Why won’t the spacecraft melt?
You can’t face off with the sun without packing the right gear.
This is why Solar Probe is equipped with a white shield
that reflects heat off the front and keeps things cool in the back.
The heat shield is made of a couple of different materials.
One is of carbon-carbon which is a lot like the graphite epoxy
you might see in your golf clubs or tennis rackets,
but it’s just been superheated.
The inside is a carbon foam
which is another form of carbon and is actually about 97% air.
It’s a very light weight way of making a very strong structure.
Nobody likes a needy explorer.
Solar Probe can take care of itself, thank you very much,
and that’s because it has autonomy software
that will keep its instruments safe and cool behind the heat shield.
We are too far away to joystick it into place,
so it basically has to always be sensing whether
whether or not the heat shield is in the right position
and correct itself if it isn’t.
There are these things called solar limb sensors,
just poking out at the very edge of the shadow.
If those get illuminated,the spacecraft knows,
“Oh, I’m going the wrong direction,” and can actually right itself.
“哦 我正驶向错误的方向” 然后自我校正
It’s important to stay hydrated in the Sun, even for a spacecraft!
Solar Probe circulates water to keep the solar cells from overheating.
It stays cool and keeps power.
Betsy: So basically water flows behind the solar arrays and into the radiators,
so the water warms up when it’s behind the solar cells
and then cools down at the radiator
that heat transfer is happening a lot like the veins in your body
Narrator: Yes, you read right: Heat is not the same as temperature.
是的 你没读错 热量和温度不一样
Temperature is a measurement, but heat is an energy transfer.
This matters because Solar Probe
will be visiting the sun’s outer layer, the corona.
Like all stars, the Sun is made of plasma.
How tightly packed that plasma is depends on the layer.
While the Sun’s corona has a very high temperature
the plasma particles are fairly spread out,
so even though the temperature in the corona is
two to three million degrees Fahrenheit,
the heat around the spacecraft is manageable.
The corona and where we are going is actually not that dense at all,
there are only couple particles.
So we think about it,those are very hot,
but we are not touching a lot of them.
It’s kind of like when you put your hand into an oven.
The oven might be at four five hundred degrees Fahrenheit,
but your hand isn’t going to be at four five hundred degrees Fahrenheit.
Thanks to its design and destination,
this cool, confident spacecraft is all set to explore.
We can just sit back and chill,
as Parker Solar Probe takes the heat.