Polarimeter to Unify the Corona and Heliosphere (PUNCH)
Mission typeHeliophysics
Start of mission
Launch dateAugust 2022[1][2]
Orbital parameters
Reference systemGeocentric
RegimeLow Earth
Altitude563 km (350 mi) [3]

Polarimeter to Unify the Corona and Heliosphere (PUNCH) is a planned mission by NASA to study the unexplored region from the middle of the solar corona out to 1 AU from the Sun. PUNCH will consist of 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. The four microsatellites are planned to be launched no later than August 2022, along with a pair of secondary satellites named Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites (TRACERS).[1][3][2]

PUNCH is led by Craig DeForest at the Southwest Research Institute in Boulder, Colorado. Including launch costs, PUNCH is being funded for no more than $165 million.[2]


The stated primary objective by PUNCH mission is "to fully discern the cross-scale physical processes, from microscale turbulence to the evolution of global-scale structures, that unify the solar corona and heliosphere." [4] In other words, the mission aims to understand how the solar corona becomes the solar wind.[5]

The two specific goals are to understand how coronal structures become the ambient solar wind, and to understand the dynamic evolution of transient structures in the young solar wind.[4] The Principal Investigator, Craig Edward DeForest from Southwest Research Institute (SwRI), thinks that such closer study will also lead to a better understanding of the causes of solar weather events like coronal mass ejections (CMEs), which can damage satellites and disrupt electrical grids and power systems on Earth.[3][2]


The mission configuration consists of a constellation of four observatories, each carrying one instrument.[6]

  • The Narrow Field Imager (NFI) sits on only one spacecraft, and is an externally occulted visible-light coronagraph.
  • The Wide Field Imagers (WFIs) are side-looking heliospheric imagers with planar-corral baffles that sit on the remaining 3 spacecraft.

The fields of view of the 3 WFIs overlap slightly with each other and with the NFI, and the instruments' operation is synchronized. The instruments operate through polarized Thomson-scatter imaging of the transition from corona to heliosphere.[7] PUNCH integrates images from its constellation of small satellites into a global composite after each orbit, covering ~6 orders of magnitude dynamic range. Through a stream of these images, PUNCH achieves 3D feature localization and accurate deep field imaging.[8] The mission builds on CYGNSS experience with smallsat constellations.[9]


PUNCH, which will operate in low Earth orbit, will work in synergy with NASA's Parker Solar Probe, and also the joint European Space Agency/NASA Solar Orbiter (SolO) mission that is due to launch in 2020.[3][7]


  1. ^ a b Press Release from: Southwest Research Institute (SwRI). 20 June 2019.
  2. ^ a b c d NASA Selects Missions to Study Our Sun, Its Effects on Space Weather. NASA Press Release. 20 June 2019.
  3. ^ a b c d NASA selects PUNCH, a new mission to study the Sun. Korey Haynes, Astronomy Now. 21 June 2019.
  4. ^ a b PUNCH: Objectives. Southwest Research Institute (SwRI). Accessed on 20 June 2019.
  5. ^ PUNCH: Motivation. Southwest Research Institute (SwRI). Accessed on 20 June 2019.
  6. ^ PUNCH Mission Instruments. Southwest Research Institute (SwRI). Accessed on 20 June 2019.
  7. ^ a b "The PUNCH Mission." (PowerPoint) Jackie Davies (UK Science Lead). 2018 Solar Missions Forum.
  8. ^ PUNCH: Science. PUNCH Home site. Southwest Research Institute (SwRI)]. Accessed on 21 June 2019.
  9. ^ PUNCH: Heritage. PUNCH Home site. Southwest Research Institute (SwRI)]. Accessed on 21 June 2019.