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This summer, NASA 's Parker Solar Probe will launch to get closer to the Sun, deeper into the solar atmosphere, than any mission before it. If the Earth was at one end of a field bar and the Sun at the other, Parker Solar Probe will be traveling within four inches of the solar surface.
Inside this part of the solar atmosphere, the Parker Solar Probe probe will provide unprecedented observations of what drives the wide range of particles, energy and heat that flow through the region and project particles to the outside. and far past Neptune.
Inside the crown, it's also, of course, incredibly hot. The spacecraft will travel through the material with temperatures greater than one million degrees Fahrenheit while being bombarded with intense sunlight.
So, why do not you melt it?
Parker Solar Probe was designed to withstand extreme conditions and temperature fluctuations for the mission. The key lies in its custom heat shield and an autonomous system that helps protect the mission from the intense light emission of the Sun, but allows the coronal material to "touch" the spacecraft.
The Science Behind Why It Was T Melt
One of the keys to understanding what keeps the spacecraft and its instruments safe is to understand the concept of heat based of the temperature. Counter-intuitively, high temperatures do not always result in heating another object.
In space, the temperature can reach thousands of degrees without providing significant heat to a given object or feeling of warmth. Why? Temperature measures the speed at which particles move, while heat measures the total amount of energy that they transfer. Particles can move quickly (high temperature), but if they are very few, they will not transmit much energy (low heat). As the space is usually empty, there are very few particles capable of transferring energy to the spacecraft.
The crown through which the Solar Parker probe passes, for example, has an extremely high temperature but a very low density. Think about the difference between putting your hand in a hot oven rather than putting it in a saucepan of boiling water (do not try it at home!) – in the oven, your hand can withstand temperatures much higher than in water it must interact with many more particles. Similarly, compared to the visible surface of the Sun, the corona is less dense, so the spacecraft interacts with fewer hot particles and does not receive as much heat.
This means that Parker Solar Probe will travel through a space with temperatures of several million degrees, the surface of the heat shield facing the sun will only be heated to around 2500 degrees Fahrenheit (about 1400 degrees Celsius ).
The Shield That Protects It
Of course, thousands of degrees Fahrenheit are still incredibly hot. (For comparison, volcanic eruptions can range from 1,200 to 2,200 F (1,200 to 1,200 C.) To resist this heat, Parker Solar Probe uses a thermal shield known as a thermal protection system. With its few centimeters in diameter and its thickness of 4.5 inches (about 115 mm), these few inches of protection mean that, just on the other side of the shield, the body of the spacecraft will seated at a comfortable temperature of 30 ° C
.] The TPS was designed by the Johns Hopkins Applied Physics Laboratory, and was built at Carbon-Carbon Advanced Technologies, using a composite carbon foam sandwiched between two carbon plates.This lightweight insulation will be accompanied by a final touch of white ceramic paint on the sun-facing plate, reflecting as much heat as possible. Tested to withstand 1,650 ° C (3,000 ° F), the GST can handle all the heat that the sun can send, thus preserving almost all of the instrumentation
The Cup That Measures the Wind
But not all Solar Parker Probe instruments will be behind the GST.
Pushing on the heat shield, The Solar Probe Cup is one of two Parker solar probe instruments that will not be protected by the heat shield. This instrument is what is called a Faraday cup, a sensor designed to measure the flow of ions and electrons and the flow angles of the solar wind. Due to the intensity of the solar atmosphere, unique technologies had to be designed to ensure that not only the instrument could survive, but also that on-board electronics could return accurate readings .
The cup itself is made of titanium zirconium-molybdenum sheets, a molybdenum alloy, with a melting point of about 4 360 F (2349 C). The chips that produce an electric field for the Solar Probe Cup are made from tungsten, a metal with the highest melting point of 6,192 C (6,192 F). Normally, lasers are used to burn the grid lines in these chips, but because of the high melting point, the acid had to be used.
Another challenge came from electronic wiring – most cables would melt due to heat radiation. so close to the Sun. To solve this problem, the team developed sapphire crystal tubes to suspend the wiring and made the niobium wires.
To make sure the instrument was ready for the harsh environment, the researchers had to mimic the intense heat radiation from the sun. laboratory. To create a level of heat worthy of a test, the researchers used a particle accelerator and IMAX-jury-fired projectors to increase their temperature. The spotlights mimicked the heat of the sun, while the particle accelerator exposed the cup to radiation to ensure that the cup could measure accelerated particles under intense conditions. To be absolutely certain that the Solar Probe Cup would withstand the hostile environment, the Odeillo solar furnace, which concentrates the sun's heat through 10,000 adjustable mirrors, was used to test the cut against solar emission intense
The Solar Probe Cup has passed its tests with flying colors. Indeed, she continued to perform better and to give clearer results, the more she was exposed to test environments. "We believe that the radiation has eliminated any potential contamination," said Justin Kasper, principal investigator for SWEAP instruments at the University of Michigan at Ann Arbor. "He cleaned himself alone."
The spacecraft that keeps its freshness
Several other designs on the spacecraft protect Parker Solar Probe from the heat. Without protection, solar panels – which use the same star energy studied to power the spacecraft – can overheat. With each approach to the Sun, the solar panels retract behind the shadow of the heat shield, leaving only a small segment exposed to the intense rays of the Sun.
But near the Sun, even greater protection is needed. Solar panels have a surprisingly simple cooling system: a heating tank that prevents coolant from freezing during launch, two radiators that will prevent refrigerant from freezing, aluminum fins to maximize the cooling surface and pumps to make circulate the liquid. The cooling system is powerful enough to cool a medium sized salon, and will keep the solar panels and instrumentation cool and running during the hot sun.
Coolant used for the system? About one gallon (3.7 liters) of demineralized water. Although there are many chemical coolants, the temperature range at which the spacecraft will be exposed ranges between 50 F (10 C) and 257 F (125 C). Very few liquids can handle these beaches like water. To prevent water from boiling at the highest temperature, it will be pressurized so that the boiling point exceeds 125 ° C (125 ° F).
Another problem with spacecraft protection is how to communicate with it. Parker Solar Probe will be largely alone on its course. It takes eight minutes to reach the Earth, which means that if the engineers had to control the spacecraft from Earth, it would be too late to fix it.
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