Literally in a few weeks, NASA is going to launch into space one of its most ambitious missions.
The solar probe Parker will make several “dives” to the surface of the Sun in order to practically “touch” it, and will thus be so close to our star than anyone before.
Parker will repeatedly pass through the solar corona, which despite its high temperature has a fairly low density.
Three of the lowest orbits Parker pass at an altitude of about 6.1 million kilometers above the surface, inside the solar corona, where temperatures reach several million degrees Celsius.
It’s pretty simple to imagine by the example of an oven and a pot of boiling water – in the oven you can hold your hand much longer, because the air has a lower density than water. Accordingly, in comparison with the surface of the Sun itself, in the corona the probe will collide with a smaller number of particles and become less heated.
This means that thermal protection will have to withstand a temperature of about 1370 degrees Celsius in order to protect the contents.
The probe shield is a kind of “sandwich” of two re-burned carbon-carbon composite plates, between which 11.5 centimeters of carbon foam, a diameter of 2.4 meters and a total weight of only 72.5 kilograms. The side facing the Sun is painted white with ceramics based paint to reflect the maximum amount of heat radiation. And the temperature behind the shield will be only 30 degrees Celsius.
Parker will maintain the orientation in space in such a way that more delicate equipment does not fall under the impact of sizzling sun rays, and the solar panels will be removed for shielding in order to avoid overheating on too “hot” sections of the trajectory. In addition, the probe is equipped with a liquid cooling system on deionized water.