With a distance of "only" 6.2 million kilometers from the sun, the spacecraft's heat shield is exposed to temperatures of over 930 degrees Celsius. However, the shield is designed to be so effective that the instruments inside the probe are expected to maintain a temperature of around 29 degrees.
The spacecraft is moving at a speed of 690,000 kilometers per hour when it explores the sun's outer atmosphere, the so-called corona, where it is several million degrees hot.
The mission's purpose is to help researchers tackle some of the sun's biggest mysteries: how solar wind arises, why the corona is warmer than the surface below it, and how massive plasma clouds that are hurled through space – coronal mass ejections – are formed.
It will not be possible to obtain any information about whether the Christmas Eve flyby was successful until contact with the probe can be reestablished on Friday, when it has flown a bit further away from the star again.
The current flyby is the first of three close passes. The two following ones, in March and June next year, are expected to lead the probe to an orbit at the same distance as the current pass if everything goes as planned.
