CAPE CANAVERAL, FLA.—NASA is sending a spacecraft straight into the sun’s glittering crown, an atmospheric region so hot and harsh any normal visitor would wither.
Set to launch early Saturday, the Parker Solar Probe is as heat-resistant as a spacecraft gets, essential for exploring our star closer than ever before.
The U.S. got a glimpse of the sun’s glowing, spiky crown, or corona, during last August’s coast-to-coast total solar eclipse. “Well, Parker Solar Probe’s going to be in there,” said project scientist Nicola Fox of Johns Hopkins University.
Parker’s lightweight heat shield is just 4 1/2 inches (11 centimetres) thick. But it can withstand 2,500 degrees Fahrenheit (1,370 degrees Celsius) as well as extreme radiation, thanks to its high-tech carbon. Although the corona reaches millions of degrees, it’s a wispy, tenuous, environment and so the spacecraft won’t need to endure such severe temperatures. The 8-foot (2.4-meter) shield will face the sun during the close solar encounters, shading the science instruments in the back and keeping them humming at a cool 80 degrees Fahrenheit (27 degrees Celsius). As one scientist notes, this is a shield Captain America would envy.