“Set the controls for the heart of the sun.” In the summer of 2018, the Parker Solar Probewill lift off from Earth. It will spend the next seven years spiraling inward tothe center of the solar system. The Parker probe will bethe first spacecraft to touch our star.
Or any star. It will brush through the halo of hot gases that form the sun’s outer atmosphere: the corona. The surface of the sunlooks placid to our eyes, but it is pierced and roiledby strong magnetic fields. The fields trap gas blowing off the Sun and lift it into glowingarcs and streamers. Scientists don’t understandhow the corona works, or why it’s hundreds of times hotter than the surface of the sun. The Parker probe willpass closer to the Sun than any mission before it.
To get that close,the spacecraft will make seven flybys of Venus over seven years, gradually tightening its elliptical orbit and shifting it closerand closer to the sun. A high-tech heat shield will protect the probe from the punishing radiation and heat of the corona. Within the shield’s shadow, the spacecraft instruments will operate at a comfortable room temperature. As the probe passes close to the sun, it will briefly become the fastest machine ever built by humans, zipping along at a brisk430,000 miles per hour.
The Parker probe isthe first NASA spacecraft to be named after a living person. Eugene Parker is an astrophysicist at the University of Chicago. In 1958, he suggestedthat the sun radiates a constant and intensestream of charged particles.
He called it the solar wind. This wind pushes out comet tails and makes the long streamersseen in solar eclipses. With the Parker Solar Probe, scientists hope to learn moreabout the sun’s turbulent corona. How it accelerates particles, and how it flings huge clouds of fiery gas outward across space. Huge waves of magnetized gas are called coronal mass ejections.
If Earth gets in the wayof one of these storms, it could be bad news. Our planet is protectedby its own magnetic field, but a direct hit fromone of these galloping clouds of particles and radiationcould disrupt satellites and force astronauts inthe space station to take shelter. In 1859, a powerful stormcalled the Carrington Event produced auroras as far south as Cuba.
A solar storm of that size today could cripple satellites and power grids around the world. If successful, the Parker probe’s mission to touch the sun may explain how solar storms form. Scientists hope it might teach us how to predict coronal outburstsmore accurately and learn how to endure them.
We’ve always dependedon the kindness of a star, here on a planet riding the gentle fringe of barely calculable forces. Living with a star is not easy. But we’re learning.