NASA's Parker solar probe to launch on a mission to touch the sun

NASA is set to launch the first space mission to enter the sun's corona, with the launch slated for Saturday from Cape Canaveral Air Force Station in Florida.

The big picture: The Parker Solar Probe stands out for just how close to the sun it plans to reach: less than 3.82 million miles away. By comparison, we live a comfortable 93 million miles away from our solar system's star. Assuming a successful launch, the probe will also become the fastest-moving man-made object ever, traveling at 340,000 miles per hour.

Why it matters: At a press conference on Thursday, project scientist Nicola Fox said that engineers and scientists have been waiting 60 years to be able to develop the right technology to build this type of probe. "We know a lot about the sun," she said, but there are key mysteries that will be unsolvable until a spacecraft can reach closer to its surface.

For example, Fox said:

"The corona that we all saw during the total solar eclipse is 300 times hotter than the surface of the sun, and we want to figure out why that’s happening. Why is this atmosphere continually expanding and accelerating away from the star?"

Answering these questions will improve scientific understanding and also help build resiliency on Earth against volatile space weather.

• The probe also honors by name Eugene Parker, a 91-year-old solar astrophysicist who developed meaningful (but initially rejected) theories about the solar corona, solar wind and the magnetic fields between Earth and the sun.
• Parker is the first namesake of a mission to be alive at the time of launch, NASA said.

How it works: The probe will encounter incredibly hot temperatures of up to 2,500°F as it travels close to the sun, and extremely cold temperatures on the other end of its orbit as it travels near Venus. Most of the probe is shielded by a 4.5-inch-thick carbon composite foam material "umbrella" that will keep it at tolerable operational temperatures.

But other parts of the probe will be exposed directly to whatever temperature extremes the spacecraft passes through. Fox said the solar probe cup, which "peeps around the heat shield" is the "bravest" piece of the probe. It's made materials like molybdenum, niobium and tungsten.

The details: The probe is set to launch at 3:33 AM on Saturday aboard a ULA Delta IV Heavy rocket, but there's a 65 minute launch window in case conditions are not ideal.

• The probe is 233 feet tall, making it almost as tall as a football field is long. It will gradually shed layers as it travels into outer space. At launch, it weighs approximately 1,400 pounds.
• In all, the project has been a long time coming, with thousands of dedicated workers that, by project manager Andy Driesman's calculations, have worked more than 4 million hours over ten years.
• You can watch the launch live on NASA TV here.