Parker Solar Probe cleared for Saturday morning launch

Aug. 10 (UPI) -- NASA engineers have cleared the Parker Solar Probe for launch.

"Teams are proceeding for liftoff on Saturday," NASA announced on Thursday.

There is a 70 percent chance of favorable weather during Saturday morning's 65-minute launch window, according to meteorologists with the U.S. Air Force 45th Space Wing. The launch window is scheduled to open at 3:33 am on Saturday.

The spacecraft has been attached to the United Launch Alliance Delta IV Heavy rocket that will carry it into space. The duo are ready and waiting on Space Launch Complex 37 at Florida's Cape Canaveral Air Force Station. After escaping Earth's gravity, NASA's Parker Solar Probe will set its sights on the sun's atmosphere.

The probe will fly closer to the sun than any spacecraft in history, reaching record speeds along the way. The mission will see the probe touch the sun. As it swings through the sun's atmosphere, Parker's instrument suite will detect and measure the movement of electrons, protons and ions -- the particles that make up the sun's corona and its solar winds.

As Eric Christian, a space scientist at NASA's Goddard Space Flight Center, told UPI, the probe's instruments will perform "the basic science." Through an improved understanding of how solar particles behave -- how they move and interact -- scientists hope to build better models of more complex solar phenomena.

"The Parker Solar Probe's observations will help us answer questions like: Why is the corona a couple million degrees hotter than the sun?" Christian said. "Another question we hope to answer is: Why is the solar wind accelerating up to very high speeds in the corona?" Christian said. "Some high-energy solar particles accelerate to nearly half the speed of light, and we don't know why."

On its record mission, PSP will fly within 4 million miles of the sun. That the spacecraft won't melt or burst into flames is thanks to its Thermal Protection System features, a 4.5-inch-thick carbon foam core sandwiched between layers of superheated carbon-carbon composite.

The outside of the heat shield will reach 2,500 degrees Fahrenheit, but its insides, instruments included, will never get hotter than 85 degrees.