The space agency will broadcast a live stream of the major announcement, which you can watch live on Express.co.uk, courtesy of NASA TV from 4PM BST (10am CDT).
NASA hopes to get a probe as close as possible to the sun where it will battle extreme temperatures and radiation.
The mission, known as the Solar Plus Probe, is set for a 2018 launch and will gather data about the sun’s outermost atmosphere known as the corona.
Temperatures in the corona are up to 500,000 degrees celsius and, for an unknown reason, far exceeds the heat of the sun’s core.
NASA hopes to send a probe to the sun
The corona is also responsible for solar winds, which NASA also hopes to gain an insight on.
The closest that a probe has got to the sun before was the Helios 2 craft, which was 27 million miles from the sun.
Temperatures in the corona are up to 500,000 degrees celsius
However, the Solar Probe Plus will, in astronomical terms, come within touching distance of the heart of our solar system as it will get just four million miles away.
"The spacecraft will explore the sun’s outer atmosphere and make critical observations" Iconic NASA space shuttle missions Wed, November 23, 2016
NASA's storied space shuttle program has seen some amazing highs, and a couple of devastating lows over the course of its 30-year history. Express Pictures looks back on the most memorable space shuttle missions.
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STS-66 launched at the Kennedy Space Center on November 3, 1994.
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The space agency said in a statement: “Placed in orbit within four million miles of the sun’s surface, and facing heat and radiation unlike any spacecraft in history, the spacecraft will explore the sun’s outer atmosphere and make critical observations that will answer decades-old questions about the physics of how stars work.
“The resulting data will improve forecasts of major space weather events that impact life on Earth, as well as satellites and astronauts in space.”