NASA's mission is to touch the sun

Considering the importance of life on earth, we know very little about the sun, the star at the center of our solar system. This will change when NASA launches the Parker Solar Probe, currently scheduled for August 11th. Parker's seven-year mission will come closer to the sun than any previous spacecraft, traveling directly into the "atmosphere" of the sun.

To understand the challenges of the NASA project, it is useful to consider some aspects of the sun. First, on the human scale, it is huge. It would take 1.3 million lands to fill its volume and it constitutes 99.86% of the mass of our solar system. The sun comprises about 70% hydrogen and 28% helium, the remaining 2% being composed of all the other elements. The equator of the huge gas ball spins once every 25.4 days. Near the poles, rotation is slower, taking up to 36 days

Hot

The sun is fueled by nuclear fusion, turning hydrogen into helium. At its base, the sun is incredibly dense and warm – its central temperature is 15 million degrees Celsius. On its surface, the temperature "goes down" to 6,000 degrees Celsius. But then things get strange. Far from the surface, in an area called the crown, the temperature rises to 3 million degrees Celsius. Why this is not clear, but rapid warming causes high-speed "solar winds" consisting of charged particles that flow into space. The presence of solar winds was first predicted by the American astrophysicist Eugene Parker in 1958; NASA's solar probe is named in his honor. This is the first time that a NASA spacecraft is named in the honor of a living person, and Parker, 90, is expected to attend the launch of the month of April. August.

Solar charged charged particle interactions with Earth's atmosphere and magnetic fields can create dawn effects in the upper atmosphere near the poles. They can also disrupt communications and the transmission of energy to the ground. Earth-orbiting satellites can be damaged by solar winds. One of the objectives of the Parker mission is to begin to understand the formation of these winds in order to predict service interruptions on the ground. "And even if the solar wind is invisible, we can see it encircle the poles like the Aurora, which are beautiful, but reveal the huge amount of energy and particles that flow into our atmosphere," he said. said Nicky Fox, a Parker Solar Probe researcher at Johns Hopkins University's Applied Physics Laboratory, in a NASA briefing. "We do not quite understand the mechanisms that drive this wind towards us, and that's what it's all about. We'll find out, "says Fox.

NASA's Parker Solar Probe must be hiding behind its heat shield to withstand the high temperatures of the sun's crown. Image: NASA)

Engineering

Much of the engineering and materials were used for the creation of the Parker Solar Probe.To resist the high temperatures of the crown, a big shield The mic (nearly eight feet in diameter) was developed to protect the spacecraft the size of a car. On its surface, the shield is made from a layer of carbon-carbon composite resistant. Behind this is a layer of 4-1 / 2 inch thick carbon structural foam that is 97% empty to insure insulation. Solar panels can retract when the probe is near the sun and extend when the probe is beyond Venus to regulate their output power. The solar panels are cooled with water to prevent overheating of solar cells during near-sun approaches.