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In a few weeks, NASA will launch one of its most ambitious projects. The Parker Solar Probe will dive and "touch" the sun – getting closer to the sun's surface, which any probe has never done before.
The three orbits closest to Parker will take it to 6.1 million kilometers from the Sun's surface and inside its outer atmosphere, or crown, where temperatures reach millions of degrees Kelvin.
It's pretty mean, but we'll come back to it later. Because it is necessary to attack these burning temperatures first.
It seems that even the most fanciful shields would melt under these conditions – after all, surface temperatures of about 733 Kelvin (460 degrees Celsius and 860 Fahrenheit) on Venus As NASA has explained , the trick to protect Parker lies in the difference between temperature and heat, as well as the density of space.
Temperature is a measure of temperature. how the fast particles move, but the heat measures the amount of energy that they actually transfer. In space, the particles move very fast, but do not transmit a lot of heat, because there is a lot of space between these particles
"The crown through which the Parker Solar probe passes through, for example, has an extremely high temperature but very low density, "Susannah Darling of NASA explained.
" Think about the difference between putting your hand in a hot oven rather than putting it in a saucepan. Boiling water (do not try it at home!) – in the oven, your hand can withstand temperatures much higher than "Similarly, compared to the visible surface of the Sun, the crown is less dense , so that the spacecraft interacts with fewer hot particles and does not get as much heat. "
This means that the heat shield, which protects most of the instruments on the probe, will only be heated up. At about 1,644 degrees Kelvin (1370 ° C or 2500 ° F).
It's a fantastic technology. It is made of two super-heated carbon-carbon composite panels, which sandwich an 11.5 cm (4.5 inch) carbon foam core.
The sun-facing side is painted bright white to reflect the possible sunlight, it is approximately 2.4 meters (8 feet) in diameter. because of the lightness of the foam, it is only 72.5 kilograms (160 pounds).
And, surprisingly, he keeps everything behind him at or below 300 Kelvin (30 ° C or 85 ° F)
The instrumentation must be able to work outside The safety of the heat shield is protected by its materials. The probe's Faraday cup, to capture charged particles in order to measure their flow, is made of titanium-zirconium-molybdenum, which has a melting point of about 2622 Kelvin
Fleas that produce the field Electrical for the instrument are forged from tungsten, the metal with the highest known melting point – 3,695 Kelvin.
And the electrical wiring is made of niobium, which has a melting point of 2750 Kelvin. Sensors on the body of the machine will help correct its orientation so that the delicate instrumentation is not exposed to the sun's burning rays
As for the solar panels, which are used to collect solar energy to power the probe, they can retract behind the thermal protection to prevent overheating when Parker gets too close to the sun.
The entire probe is cooled by pressurized demineralized water, the liquid best able to withstand the extreme temperatures to which Parker will be exposed.
admit, it is a lot of ingenious engineering. We can not wait to see what Parker has taught us about the Sun, its crazy wind and its wildest outdoor atmosphere.
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