spase://NASA/Observatory/PUNCH

The PUNCH (Polarimeter to Unify the Corona and Heliosphere) mission is designed to image and track sunlight scattered off of free electrons in the boundary zone between the outer solar corona and the young solar wind and to track in 3D coronal mass ejections that can drive large space weather events near Earth. The primary scientific objectives are to understand: (1) how coronal structures become the ambient solar wind; and (2) the evolution of transient structures that punctuate the young solar wind such as large coronal mass ejections, shocks, and other transient effects.

The baseline mission configuration consists of a constellation of four suitcase-sized spacecraft: PUNCH Narrow Field Imager satellite (PUNCH-NFI) and the three PUNCH Wide Field Imager satellites (PUNCH-WFI 1, PUNCH-WFI 2, and PUNCH-WFI 3).

PUNCH-NFI carries the Narrow Field Imager (NFI) which is an externally occulted visible-light coronagraph to observe the inner heliosphere from 5.4 to 32 solar radii with an annular, sun-centered field of view. PUNCH-WFI-1, PUNCH-WFI-2, and PUNCH-WFI-3 carry identical Wide Field Imagers (WFI), which are side-looking polarizing heliospheric imagers with planar-corral baffles. Together these three satellites the inner heliosphere observe the inner heliosphere the corona and solar wind over a 90-degree field of view (45 degrees solar elongation). As each satellite orbits Earth, the NFI scans the entire range of solar azimuths once per orbit. Together, these four instruments form a single virtual instrument covering the entire inner solar system continuously from about 6 to 180 solar radii (1.5 to 45 degrees solar elongation).

All four spacecraft were launched together on the same vehicle along with the SPHEREx spacecraft. To enable a continuous, complete view of the corona and inner solar system, the four satellites will be placed in a polar, low-Earth orbit and spread out along the day-night line, with a nominal mission lifetime of two years.