Polarimeter to Unify the Corona and Heliosphere
Polarimeter to Unify the Corona and Heliosphere (PUNCH), also known as SMEX-15, is a mission by NASA to study the unexplored region from the middle of the solar corona out to 1 AU from the Sun. The PUNCH flight assets are a constellation of four microsatellites that through continuous 3D deep-field imaging, will observe the corona and heliosphere as elements of a single, connected system.
Source: Wikipedia — Polarimeter to Unify the Corona and Heliosphere (CC BY-SA 4.0)