STORY WRITTEN TO CBS NEWS & USED WITH PERMISSION
NASA executives Thursday cleared $ 1.5 billion Parker Solar Probe for launch at the start of Saturday on a daring mission to "touch the sun", which repeatedly flies through its outer atmosphere to find out why The flaming corona is million degrees warmer than our star's visible surface.
The spacecraft's instrument will also chart the solar magnetic fields, the flow of electrically charged particles that are constantly blown into space in explosive outbreaks and the mechanism that accelerates these particles to extreme speeds.
The goal is to understand and better predict the behavior of the solar wind that triggers auroral screens on Earth and sometimes causes chaos with power grids and satellites.
"This space weather has a direct influence, not always positive, on our technology in space, our spacecraft, it interferes with our communications, it creates a dangerous environment for astronauts, and in extreme extremes can actually affect our power grids here on earth" , says Alex Young, deputy director of NASA's heliophysics science division.
"So it is essential for us to anticipate this space weather as we predict weather on earth."
As for the sun's corona, the glowing glare of shimmering light seen under a full eclipse, scientists hope that Parker Solar Probe can answer one of their most basic questions.
"We are accustomed to the idea that if I stand next to a campfire and I'm leaving it gets cooler," said Young. "But this is not what's happening to the sun. As we walk from the sun's surface, which is 10,000 degrees and goes up into the corona, we find ourselves fast in millions of degrees."
"Here's a fundamental issue that drives not just how this star works, our sun, but actually all stars in the universe. And then these are the three basic questions we want to address: the wind speed of the sun, this eruption phenomenon, the solar storm, and how is the corona heated? "
Nicola Fox, the Parker Project Researcher at Johns Hopkins University's Applied Physics Laboratory, described the solar probe as" the coolest hottest mission under the sun. "
" Until you actually go there and touch the sun, can not you really answer these questions, "she said." Why is the corona warmer than the sun's surface? It defies the laws of nature. It's like water flowing upwards, it should not happen. Why in this region is the sunshine suddenly so energetic that it releases from the sunshine and baths all the planets? We have been unable to answer these questions.
But Parker Solar Probe was built to do just that.
Landing on top of a heavy-lift United Launch Alliance Delta 4 rocket, Parker will blow from Pad 37 at Cape Canaveral Air Force Station at 3:33 pm EDT ( GMT-4) Saturday. The forecaster presupposes a 70-percent chance of acceptable weather.
The powerful Delta 4 Heavy, ULA's most powerful launcher, will only make its 10th flight since 2004. It is equipped with a Northrup Grumman solid fuel upper stage that will act to release the Parker probe out of the earth's 18-mile circulation around the sun so that it can fall inward for the first of seven gravitational helmets of Venus over a planned seven-year mission.
"It's a railing of a rocket, "said Fox at Delta 4." We must go so fast that we must lose the influence of the earth. "
Venus flybys will help shape Parker's track and eventually put the spacecraft into an elliptical orbit with a low point of just 3.8 million miles from the visible area of the sun and a high point around Venus orbit.
To express it in perspective, if the Earth and the Sun were at opposite ends of a football field, Parker probe would lie on four-yard line and the nearest sun in close proximity.
Along with being the first spacecraft to fly so close to a star, Parker will also be the fastest, streaking through the outer coron of approximately 430,000 mph – fast enough to fly from Washington, DC, to Tokyo in less than a minute.
These extremes will not be seen until later, but Parker will collect data during all their travels around the sun, from the beginning with its The first close meeting three months after the start.
In our very first airfield (by the sun) we get a little more than 15 million miles away from the sun surface, Fox said. "We are still three times closer than ever before. The spacecraft stays over the same area of the sun for many, many days, so we can do some incredible science at our very first airport."
While the corona blows in millions degrees it is a tough environment and the heat transferred to spacecraft becomes much smaller. Nevertheless, Parker's four-inch thick 160-pound carbon-composite heat shield will be exposed to approximately 2500 degrees Fahrenheit in the immediate approach, hotter than liquid lava.
But at the back of the heat shield, where Parker's four instruments, its flight computer and other critical systems are located, temperatures will be maintained at a relatively cool 85 degrees. Its water-cooled solar panels will be drawn behind the heat shield in close proximity with only the tips exposed to the sun's radiant light and heat.
"You can put your hand in your oven and you will not be burned unless you actually touch a surface," said Fox. "And that's the same. Corona is a very dense plasma.
"If you think of the amount of particles that actually hit the heat shield and deposit the heat, the whole thing is heated to 2,500 degrees Fahrenheit. Again, I'd just say you do not touch the oven surface, do not touch the plasma at three million degrees!"  Sufficiently, the spacecraft is named for Eugene Parker, the University of Chicago researcher who first theorized Current 91. Parker, the first living scientist with a spacecraft named his honor, flew to the Florida Coast to witness his first rocket launch.
"Because this is an assignment in unknown territory, we must be prepared for some surprises, things we never thought of or things we believed in but were not correct," he said in a recently summarized briefing. "The warming, especially during stormy times when the sun has a lot of stains and activity, this is where you really do not know what to find."
Parker Solar Probe is equipped with four instruments. FIELDS instrument charts the solar electric and magnetic fields, measures waves and turbulence in the star's atmosphere to help researchers understand how magnetic field lines can blow each other and adjust each other.
Wide-Field Imager for Parker Solar Probe, or WISPR, will photograph the large-scale structure of the korona before spacecraft flies into it, studying coronary mass protrusions, rays and other phenomena.
The alfa and proton study Solar Wind Electron, or SWEAP, will use two instruments to characterize the particles that form the solar wind, measure their velocity, density and temperature.
Finally, the integrated scientific survey of the sun or ISOIS builds on two instruments for measuring particle energies, shedding light on their origin and how they were accelerated.
"Science is groundbreaking, it's convincing, it's confused scientists and puzzled us for decades and decades and decades," Fo x said. "We're going to fly this mission now."