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Meet Parker Solar Probe, Our Mission to Touch the Sun

In just a few weeks, we're launching a spacecraft to get closer to the Sun than any human-made object has ever gone.

The mission, called Parker Solar Probe, is outfitted with a lineup of instruments to measure the Sun's particles, magnetic and electric fields, solar wind and more – all to help us better understand our star, and, by extension, stars everywhere in the universe.

Parker Solar Probe is about the size of a small car, and after launch – scheduled for no earlier than Aug. 6, 2018 – it will swing by Venus on its way to the Sun, using a maneuver called a gravity assist to draw its orbit closer to our star. Just three months after launch, Parker Solar Probe will make its first close approach to the Sun – the first of 24 throughout its seven-year mission.

Though Parker Solar Probe will get closer and closer to the Sun with each orbit, the first approach will already place the spacecraft as the closest-ever human-made object to the Sun, swinging by at 15 million miles from its surface. This distance places it well within the corona, a region of the Sun's outer atmosphere that scientists think holds clues to some of the Sun's fundamental physics.

For comparison, Mercury orbits at about 36 million miles from the Sun, and the previous record holder – Helios 2, in 1976 – came within 27 million miles of the solar surface. 

Humanity has studied the Sun for thousands of years, and our modern understanding of the Sun was revolutionized some 60 years ago with the start of the Space Age. We've come to understand that the Sun affects Earth in more ways than just providing heat and light – it's an active and dynamic star that releases solar storms that influence Earth and other worlds throughout the solar system. The Sun's activity can trigger the aurora, cause satellite and communications disruptions, and even – in extreme cases – lead to power outages.

Much of the Sun's influence on us is embedded in the solar wind, the Sun's constant outflow of magnetized material that can interact with Earth's magnetic field. One of the earliest papers theorizing the solar wind was written by Dr. Gene Parker, after whom the mission is named.

Though we understand the Sun better than we ever have before, there are still big questions left to be answered, and that's where scientists hope Parker Solar Probe will help.  

First, there's the coronal heating problem. This refers to the counterintuitive truth that the Sun's atmosphere – the corona – is much, much hotter than its surface, even though the surface is millions of miles closer to the Sun's energy source at its core. Scientists hope Parker Solar Probe's in situ and remote measurements will help uncover the mechanism that carries so much energy up into the upper atmosphere.

Second, scientists hope to better understand the solar wind. At some point on its journey from the Sun out into space, the solar wind is accelerated to supersonic speeds and heated to extraordinary temperatures. Right now, we measure solar wind primarily with a group of satellites clustered around Lagrange point 1, a spot in space between the Sun and Earth some 1 million miles from us. 

By the time the solar wind reaches these satellites, it has traveled about 92 million miles already, blending together the signatures that could shed light on the acceleration process. Parker Solar Probe, on the other hand, will make similar measurements less than 4 million miles from the solar surface – much closer to the solar wind's origin point and the regions of interest.

Scientists also hope that Parker Solar Probe will uncover the mechanisms at work behind the acceleration of solar energetic particles, which can reach speeds more than half as fast as the speed of light as they rocket away from the Sun! Such particles can interfere with satellite electronics, especially for satellites outside of Earth's magnetic field.

Parker Solar Probe will launch from Space Launch Complex 37 at Cape Canaveral Air Force Station, adjacent to NASA’s Kennedy Space Center in Florida. Because of the enormous speed required to achieve its solar orbit, the spacecraft will launch on a United Launch Alliance Delta IV Heavy, one of the most powerful rockets in the world.

Stay tuned over the next few weeks to learn more about Parker Solar Probe's science and follow along with its journey to launch. We'll be posting updates here on Tumblr, on Twitter and Facebook, and at nasa.gov/solarprobe.

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