On April 28, 2021, at 933 UT (3:33 a.m. Eastern Daylight Time), NASA’s Parker Solar Probe reached the sun’s extended solar atmosphere, known as the corona, and spent five hours there. The spacecraft is the first to enter the outer boundaries of our sun.

The results, published in Physical Review Letters, were announced in a press conference at the American Geophysical Union Fall Meeting 2021 on December 14. The manuscript is open-access and freely available to download.

“This marks the achievement of the primary objective of the Parker mission and a new era for understanding the physics of the corona,” said Justin C. Kasper, the first author, Deputy Chief Technology Officer at BWX Technologies, and a professor at the University of Michigan. The mission is led by the Johns Hopkins University Applied Physics Laboratory (JHU/APL).