Polarimeter to Unify the Corona and Heliosphere (PUNCH)
PUNCH is a NASA Small Explorer mission that will make global, 3D observations of the young solar wind, from the outermost solar atmosphere to the inner heliosphere. Images of unprecedented quality will help to close a 60-year gap in measurement and understanding of what occurs in this region of space. PUNCH is scheduled to launch after Q3 of 2023.
The PUNCH mission consists of a constellation of four small satellites in Sun-synchronous, low Earth orbit that together will produce deep-field, continuous, 3D images of the solar corona as it makes a transition to the young solar wind: from 1.5° (6 R☉) to 45° (180 R☉) from the Sun. The PUNCH cameras sense normal visible light and its linear polarization which allows the 3D location of solar wind features to be measured.