No space agency has ever sent a spacecraft so close to the sun before. Previous attempts have inched as near as 25 million miles from the surface, but Parker Solar Probe will orbit the sun at an average distance of only 4 million miles. In order to do this and not melt into a gooey pile of metal, it is equipped with a revolutionary heat shield. The surface of the sun averages around 10,000 degrees Fahrenheit, but Parker Solar Probe won't get that close. The team expects the spacecraft to reach temperatures of around 2,500 degrees Fahrenheit at most during its 6.5-year mission, and it's built to beat that heat without a problem.