Polarimeter to Unify the Corona and Heliosphere
Mission typeHeliophysics
COSPAR ID Edit this at Wikidata
Spacecraft properties
Spacecraft typeOrbiters (4)
ManufacturerSouthwest Research Institute (SwRI)
Launch mass40 kg (each)
Start of mission
Launch dateApril 2025 (planned)[1]
Orbital parameters
Reference systemGeocentric orbit
RegimeSun-synchronous orbit
Altitude570 km [2]
Narrow Field Imager (NFI) - 1 satellite
Wide Field Imagers (WFIs) - 3 satellites
Explorer program
← IXPE (Explorer 97)

Polarimeter to Unify the Corona and Heliosphere (PUNCH) is a future 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 were initially scheduled to be launched in October 2023, but they have later been moved to an April 2025 launch in rideshare with SPHEREx.[1]

On 20 June 2019, NASA announced that PUNCH and TRACERS were the winning candidates to become the next missions in the agency's Small Explorer program (SMEX).[3]

PUNCH is led by Craig Edward DeForest at the Southwest Research Institute (SwRI) in Boulder, Colorado. Including launch costs, PUNCH is being funded for no more than US$165 million.[3]


The stated primary objective by PUNCH's 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.[2][3]

The more we understand what drives space weather and its interaction with the Earth and lunar systems, the more we can mitigate its effects – including safeguarding astronauts and technology crucial to NASA's Artemis program to the Moon.[3]


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

The fields of view (FoV) 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 Cyclone Global Navigation Satellite System (CYGNSS) experience with smallsat constellations.[9]


Phase B will last over a full year. Throughout the process, SwRI is collaborating with the Naval Research Laboratory (NRL) and the Rutherford Appleton Laboratory in Oxfordshire, England, United Kingdom.

PUNCH, which will operate in low Earth orbit, will work in synergy with NASA's Parker Solar Probe and the ESA's Solar Orbiter.[2][7]

See also

Explorer program


  1. ^ a b Interrante, Abbey (3 August 2022). "PUNCH Announces Rideshare with SPHEREx and New Launch Date". NASA. Retrieved 3 August 2022.
  2. ^ a b c NASA selects PUNCH, a new mission to study the Sun Korey Haynes, Astronomy Now, 21 June 2019
  3. ^ a b c d NASA Selects Missions to Study Our Sun, Its Effects on Space Weather NASA, 20 June 2019 Public Domain This article incorporates text from this source, which is in the public domain.
  4. ^ a b PUNCH: Objectives Southwest Research Institute (SwRI), Accessed on 24 November 2020
  5. ^ PUNCH: What is Heliophysics?, Southwest Research Institute (SwRI), Accessed on 24 November 2020
  6. ^ PUNCH: The Mission Southwest Research Institute (SwRI) Accessed on 24 November 2020
  7. ^ a b "The PUNCH Mission" (PowerPoint), Jackie Davies (UK Science Lead), 2018 Solar Missions Forum
  8. ^ PUNCH: From Observations to Science, PUNCH Home site, Southwest Research Institute (SwRI)], Accessed on 24 November 2020
  9. ^ PUNCH: Heritage PUNCH Home site, Southwest Research Institute (SwRI)] Accessed on 21 June 2019