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NASA spacecraft ‘touches’ the Sun for the first time ever

nature.com

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Re: NASA spacecraft ‘touches’ the Sun for the first time ever

#41

Post by wongarsu »

Aachen wrote: post #37
threefour wrote: post #5

If you’re curious why it won’t melt: https://www.nasa.gov/feature/goddard/2018/traveling-to-the-s...

Relevant part: the capturing cups are of metals with high melting points, plus > The corona through which Parker Solar Probe flies, for example, has an extremely high temperature but very low density. Think of the difference between putting your hand in a hot oven versus putting it in a pot of boiling water And for the rest of the craft there is a highly reflective heat shield.

Also spending most of it's orbit pretty far away from the sun. You can move your hand though an open flame with no issues, but if you keep it in the flame it will get burned.

Re: NASA spacecraft ‘touches’ the Sun for the first time ever

#42

Post by cableshaft »

pcl wrote: post #18
lordnacho wrote: post #16

Earlier quoted context omitted.

Basically not much heat is transferred because there's not many particles to do the transfer, like a hot oven. What I didn't understand was the coolant. It's got to dump whatever heat it picks up somewhere? Just a big radiator?

The article puts some numbers on it, as well: > That means that while Parker Solar Probe will be traveling through a space with temperatures of several million degrees, the surface of the heat shield that faces the Sun will only get heated to about 2,500 degrees Fahrenheit (about 1,400 degrees Celsius).

I'm a little curious how they were able to determine this before even sending a craft there and measuring it and have a high degree of confidence in its accuracy.

Re: NASA spacecraft ‘touches’ the Sun for the first time ever

#44

Post by criddell »

HPsquared wrote: post #20
lordnacho wrote: post #16

Earlier quoted context omitted.

Basically not much heat is transferred because there's not many particles to do the transfer, like a hot oven. What I didn't understand was the coolant. It's got to dump whatever heat it picks up somewhere? Just a big radiator?

The thing about space is, heat transfer is all radiative. The "dark" side of the probe, which is in its own shadow, faces the darkness of space (which is very cold indeed). Therefore you can put insulation on the side facing the sun, and a radiator on the dark side to remove any heat that gets through the insulation.

But space is a vacuum which is a pretty good thermal insulator. How are they dumping the heat?

Re: NASA spacecraft ‘touches’ the Sun for the first time ever

#45

Post by moron4hire »

ivanhoe wrote: post #28

I get the heat part (well, after reading the explanations in the article that is), but how do they send the data back to Earth, considering the amount of EM noise that close to the Sun?

It doesn't. While it's near the sun, it's only collecting data. It transmits the data when its elliptical orbit takes it further away from the Sun.

https://www.space.com/41457-parker-solar-probe-what-next-sun...

Re: NASA spacecraft ‘touches’ the Sun for the first time ever

#47

Post by chengiz »

Aachen wrote: post #37
threefour wrote: post #5

If you’re curious why it won’t melt: https://www.nasa.gov/feature/goddard/2018/traveling-to-the-s...

Relevant part: the capturing cups are of metals with high melting points, plus > The corona through which Parker Solar Probe flies, for example, has an extremely high temperature but very low density. Think of the difference between putting your hand in a hot oven versus putting it in a pot of boiling water And for the rest of the craft there is a highly reflective heat shield.

Not sure I get the oven analogy. If I stick my hand in for a few seconds, sure, but if I was in the oven, I'll burn and die there too.

Re: NASA spacecraft ‘touches’ the Sun for the first time ever

#48

Post by DecoPerson »

criddell wrote: post #44
HPsquared wrote: post #20

Earlier quoted context omitted.

The thing about space is, heat transfer is all radiative. The "dark" side of the probe, which is in its own shadow, faces the darkness of space (which is very cold indeed). Therefore you can put insulation on the side facing the sun, and a radiator on the dark side to remove any heat that gets through the insulation.

But space is a vacuum which is a pretty good thermal insulator. How are they dumping the heat?

Pick a material for the surface of the radiator which has high emissivity.

That is, when the material gets warm, it will convert the thermal energy to electromagnetic energy (light). Some of this light will escape, leading to a cooling effect.

This is known as “incandescence” or “black body radiation”, and it’s why metals glow red hot when they’re heated to a certain temperature. (Though it’s not always red, it can be white, blue, or even UV. Animals are warm enough to glow in infrared, which is what thermal cameras detect).

Re: NASA spacecraft ‘touches’ the Sun for the first time ever

#49

Post by haimez »

criddell wrote: post #44
HPsquared wrote: post #20

Earlier quoted context omitted.

The thing about space is, heat transfer is all radiative. The "dark" side of the probe, which is in its own shadow, faces the darkness of space (which is very cold indeed). Therefore you can put insulation on the side facing the sun, and a radiator on the dark side to remove any heat that gets through the insulation.

But space is a vacuum which is a pretty good thermal insulator. How are they dumping the heat?

The physical mechanism is radiative cooling: https://en.m.wikipedia.org/wiki/Radiative_cooling

More details about the specific mechanism on the Parker Solar Probe’s cooling system: https://blogs.nasa.gov/parkersolarprobe/2018/09/14/parker-so...

Re: NASA spacecraft ‘touches’ the Sun for the first time ever

#50

Post by hugh-avherald »

chengiz wrote: post #47
Aachen wrote: post #37

Earlier quoted context omitted.

Relevant part: the capturing cups are of metals with high melting points, plus > The corona through which Parker Solar Probe flies, for example, has an extremely high temperature but very low density. Think of the difference between putting your hand in a hot oven versus putting it in a pot of boiling water And for the rest of the craft there is a highly reflective heat shield.

Not sure I get the oven analogy. If I stick my hand in for a few seconds, sure, but if I was in the oven, I'll burn and die there too.

It's in an elliptical orbit that also flies by Venus so it's like putting your hand for a few seconds twice a year.
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