NASA Probe to Touch the Sun’s Corona

Posted on 31 May 2017

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A NASA heat shield technology can, in the size of a small car, create a room temperature space when the heat shield is facing temperatures of 2,500 F (1,377 C). I was surprised that they can navigate this probe to avoid the full heat of the corona, which can reach 3.5 million degrees F.

In order to unlock the mysteries of the sun’s atmosphere, Parker Solar Probe will use Venus’ gravity during seven flybys over nearly seven years to gradually bring its orbit closer to the sun. The spacecraft will fly through the sun’s atmosphere as close as 3.9 million miles to our star’s surface, well within the orbit of Mercury and more than seven times closer than any spacecraft has come before. (Earth’s average distance to the sun is 93 million miles.)
Flying into the outermost part of the sun’s atmosphere, known as the corona, for the first time, Parker Solar Probe will employ a combination of in situ measurements and imaging to revolutionize our understanding of the corona and expand our knowledge of the origin and evolution of the solar wind. It will also make critical contributions to our ability to forecast changes in Earth’s space environment that affect life and technology on Earth.

… At closest approach to the sun, the front of Parker Solar Probe’s solar shield faces temperatures approaching 2,500 F (1,377 C). The spacecraft’s payload will be near room temperature.

To perform these unprecedented investigations, the spacecraft and instruments will be protected from the sun’s heat by a 4.5-inch-thick (11.43 cm) carbon-composite shield, which will need to withstand temperatures outside the spacecraft that reach nearly 2,500 F (1,377 C).

… Parker Solar Probe will carry four instrument suites designed to study magnetic fields, plasma and energetic particles, and image the solar wind.

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In the summer of 2018, NASA will launch a one-of-a-kind mission directly into the sun’s atmosphere in an effort to bring back answers to solar physics questions that have long puzzled scientists.
The mission, which has been discussed since at least 2008, is centered around an unmanned probe that will fly within four million miles of the sun. The probe will be subjected to heat unlike that which any other spacecraft has ever previously endured, according to the space agency. …

“It’s a spacecraft loaded with technological breakthroughs that will solve many of the largest mysteries about our star, including finding out why the sun’s corona is so much hotter than its surface. … 

The mission will launch during a 20-day window that opens on July 31, 2018, and is part of NASA’s “Living With a Star” program, which is designed to study the sun and its interactions with Earth and the broader solar system.

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 … The temperature of the sun varies tremendously, and not in ways you might realize.

At the core of the sun, gravitational attraction produces immense pressure and temperature, which can reach more than 27 million degrees Fahrenheit (15 million degrees Celsius). Hydrogen atoms get compressed and fuse together, creating helium. This process is called nuclear fusion.
Nuclear fusion produces huge amounts of energy. The energy radiates outward to the sun’s surface, atmosphere and beyond. From the core, energy moves to the radiative zone, where it bounces around for up to 1 million years before moving up to the convective zone, the upper layer of the sun’s interior. The temperature here drops below 3.5 million degrees F (2 million degrees C). Large bubbles of hot plasma form a soup of ionized atoms and move upwards to the photosphere.
The temperature in the photosphere is about 10,000 degrees F (5,500 degrees C). It is here that the sun’s radiation is detected as visible light. Sunspots on the photosphere are cooler and darker than the surrounding area. At the center of big sunspots the temperature can be as low as 7,300 degrees F (4,000 degrees C).
The chromosphere, the next layer of the sun’s atmosphere is a bit cooler — about 7,800 degrees F (4,320 degrees C). Visible light from the chromosphere is usually too weak to be seen against the brighter photosphere, but during total solar eclipses, when the moon covers the photosphere, the chromosphere can be seen as a red rim around the sun.
Temperatures rise dramatically in the corona, which can also only be seen during an eclipse as plasma streams outward like points on a crown. The corona can get about 3.5 million degrees F (2 million degrees C). As the corona cools, losing heat and radiation, matter is blown off as the solar wind.
The sun is the largest and most massive object in the solar system. It is about 93 million miles (149.5 million km) from Earth. … The sun’s light and heat takes about eight minutes to reach us, which leads to another way to state the distance to the sun: 8 light-minutes.

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It is strange but true that the sun is not  cooler the farther you are from the center. Why is the corona hotter than the surface?

For years astronomers have looked for the elusive mechanism that causes some stars to have a corona that is almost 200 times hotter than their photosphere, despite being further away from the heat source at the star’s core. It is believed that the cause of the increased temperature is due to magnetohydrodynamic (MHD) waves that distribute the energy generated below the star’s surface to the outer layers of the Sun’s atmosphere

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TrueStrange.com

Posted in: Space, Technology