This Christmas Eve, a vehicle will travel at incomprehensible speed around a celestial object to bring wonder to the people of Earth — and it’s not Santa’s sleigh.

On Dec. 24 at 6:40 a.m. Eastern time, the Parker Solar Probe, a NASA spacecraft, will pass within 3.8 million miles of the sun’s surface, more than seven times closer than any previous mission has. While surfing across the corona, the sun’s outer atmosphere, Parker will surpass the blistering speed of 430,000 miles per hour, breaking its own record as the fastest object ever made by humans.

“It’s a voyage of discovery,” said Nicky Fox, associate administrator of NASA’s Science Mission Directorate. “We really are going into the unknown. Nothing has flown through the atmosphere of a star, and no other mission will for a long time.”

Since its launch in 2018, Parker has inched progressively closer to the sun during 21 solar flybys, called perihelions. The mission, a collaboration between NASA and the Johns Hopkins Applied Physics Laboratory, has revolutionized our understanding of the sun, spotted comets, snapped captivating pictures and yielded insights about Venus.

In addition to its scientific haul, Parker has overcome the technical challenges of flying so close to the sun that the probe’s heat shield must contend with temperatures of nearly 2,000 degrees Fahrenheit.