On Wednesday, NASA will make an announcement about its Solar Probe Plus mission, which will fly into the sun’s atmosphere.

The spacecraft, which will launch in the summer of 2018, will explore the sun as it never has been explored before: it will fly 6.4 million kilometres above the sun’s surface where the temperature will be a searing 1,400 C.

The sun is made up of several zones and layers. Its outermost layer is the corona, part of its atmosphere. 

The sun atmosphere

The sun and its atmosphere consist of several zones or layers. (NASA/Goddard)

The corona is a very active part of the sun, producing solar wind, solar flares and coronal mass ejections, all of which influence space weather and conditions on Earth.

An example is the Quebec blackout of March 13,1989. A solar flare erupted from the sun followed by a coronal mass ejection (CME). The particles raced towards Earth and slammed into our magnetic field.

While the results were visually stunning, producing the northern lights, it also caused electric currents to travel along the ground. Those currents found a weakness in the Quebec power grid which overloaded and failed. Thousands were left in the dark and cold.

Though measures have been put into place to prevent something like that from reoccurring, space weather forecasters would like to be able to better predict the activity at the source, the sun.

This is part of Solar Probe Plus’s mission — to uncover why the corona so much hotter than another layer, the photosphere. It also will study the solar wind.

Solar Probe Plus will fly closer to the sun than any other spacecraft before it. In 1974, Helios 1 passed within 45 million kilometres of the sun’s surface and Helios 2 within 43.4 million kilometres.