NASA is set to announce a new mission to fly directly into the Sun's atmosphere.

The US space agency said the Solar Probe Plus, which will help "revolutionise our understanding of the Sun", is expected to launch in the summer of next year.

The probe will orbit within 6.2 million kilometres of the Sun's surface and withstand temperatures of nearly 1,377 degrees Celsius.

According to NASA, the spacecraft will come "well within the orbit of Mercury" and will be "more than seven times closer than any spacecraft has come before".

The last time a spacecraft came close to the star's surface was in 1976, when Helios 2 achieved perihelion - point of the orbit at which it was closest to the Sun - 43 million kilometres.

NASA said in a statement: "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."

The Solar Probe Plus will be protected from the Sun's brutal heat and radiation by a special carbon-composite heat shield that is 11.43cm thick.

The announcement will be made on a live webcast on NASA TV later on today.