It took 60 years, but scientists and engineers are finally ready to reach for the stars ̵
This summer, NASA will launch the Parker Solar Probe, a stunningly heat-resistant spacecraft designed to float closer to the surface of the sun than any other spaceship. It will fly from the burning surface within about 6 million kilometers, more than seven times closer than previous vehicles. If everything goes according to plan, the vehicle will race at 724.205 km / h and direct its unique heat shield perfectly to the surface when it makes the next approaches. In about seven years, it will pass 24 orbits around the sun and seven times on Venus.
Meanwhile, the Parker probe will collect a constellation of data to answer scientists' burning questions – and to solve some secreting secrets – about the hot plasma sphere that illuminates our solar system. It will try to finally understand why the atmosphere of the sun is 300 times hotter than its surface, which is even mild 5,727 degrees Celsius. This fact contradicts basic physics and is still unclear. One of the leading hypotheses for heat displacement comes from the famous physicist Eugene Parker, after whom the probe is named. In the mid-1950s, Parker hypothesized that the sun's overheated corona can be explained by a complex system of plasma, magnetic fields, and energetic particles that produce solar blasts called "nanoflares."
Scientists are thirsty for detailed data on these potential explosions and the so-called solar wind cascade. With this data, they can put their hypotheses to the test. The data on these sunny phenomena not only help to understand the coronal heat, but also help clear up ill-understood space weather that could have devastating consequences on satellites and power lines on Earth.
Overall, the Parker Solar Probe project is "the coolest, hottest mission under the sun," Nicky Fox told reporters on Wednesday in a press review of the spacecraft at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Fox is a Parker Solar Probe project scientist with the Johns Hopkins University Applied Physics Lab. She introduced the mission as "the first encounter of humanity with a star" and an "extremely historical" one.
The original idea of reaching the sun with a spaceship came before the NASA operation in 1958, she noted. But it took six decades for the technology to catch the scientists' dreams. The Parker Solar Probe is the realization of these visions – armed with the mother of all heat shields.
Taking the Heat
The surface of the spacecraft will withstand the brutal temperatures of 11,43 cm (4.5 inches) thick carbon – composite screen coated with a white ceramic layer. The outer white layer allows the probe to reflect back as much radiation as possible. In the next approaches, the outer layer will be exposed to temperatures of 1,400 degrees Celsius. But the bottom, according to leading aerospace engineer Betsy Congdon, who spoke to Ars, is 315-371 degrees Celsius.
The shield sits on a large radiator with a titanium frame. This structure keeps the payload of the spacecraft in a cool, dark shade as the ship flies through the sun. Indeed, the scientists and engineers who designed the ship were more concerned that their scientific instruments and equipment would freeze rather than melt during the mission. To avoid this, the instruments, which are attached to the outside of the boat, wrapped in thermal blankets and combined with individual solar-powered heaters. These hold the instruments at a pleasant temperature of about 28 degrees Celsius.
The solar panels that drive these instruments – as well as other electronics on board – are located on wing-like flaps that extend below the antenna cooler. These arrays, which are exposed to intense radiation, are designed specifically for the heat and equipped with its own cooling system. This system includes a gallon-sized water tank and a pump inside the vehicle that allows cool water to flow through the arrays to keep them at operating temperature.
The interior of the boat also contains much of the communications equipment and a small fuel tank that powers the ship's engines. These will autonomously fire in short bursts to keep the probe aligned so that the heat shield is always perfectly aligned with the sun's surface. If the probe deviates more than one degree from the heading, some of the heat-sensitive payload could be exposed to radiation from the sun, causing the ship to melt and deteriorate. But the ship has many layoffs to prevent that, Fox Ars assured.
While the craft is trying not to melt or freeze, a number of scientific instruments will collect coveted sun-data. According to Adam Szabo, head of NASA's Heliospheric Physics Laboratory, there are basically four types of data the instruments are looking for. The first is the local measurement of solar winds, so there are a number of instruments that measure particles, including protons, electrons, small amounts of ionized helium, and traces of heavy elements. "The instruments measure how fast they are, how hot they are, how many of them they are," he told Ars.
A second set of instruments measures magnetic and electric fields that can "radically complicate" the behavior of floating ions. The third group tries to capture the particles with the highest energy. Finally, there are a number of cameras that capture close-ups of plasma when it comes from the corona.
These instruments and the rest of the boat are being tested. On Wednesday, scientists and engineers at Goddard inspected the equipment inside the vehicle before closing the doors. Over the next few days, the ship will be sent to NASA's Kennedy Space Center in Florida for further testing.
Currently the launch date is July 31st. On this timeline, it will fly on Venus at the end of September and reach the Corona until the beginning of November. Scientists expect to begin downloading data in March 2019, astrophysicist Nicki Viall told Ars.
With these data: "I think we'll answer a lot of questions and ask a whole new set of questions that we have not even thought of," said Viall.
The ship is said to orbit the Sun 24 times in about six years and eleven months, but Fox told Ars that the team expects it will take another year or two beyond that. When the fuel runs out, the Parker Solar Probe will be in a stable orbit, but it will start to tip over and expose its sensitive side to the searing heat. From there it decays into smaller and smaller parts and becomes part of the dust cloud.