23 Apr 2018



The Polarimeter to Unify the Corona and Heliosphere (PUNCH) mission is a NASA small-explorer (SMEX) mission: its primary science goal is to fully discern the cross-scale physical processes that unify the solar corona and heliosphere.


​​​​​​​​Artists impression of the four PUNCH spacecraft

Credit: Southwest Research Institute

​The PUNCH mission will use pioneering scientific and technological concepts to understand how the solar corona – the outer atmosphere of the Sun – evolves into the heliosphere, the huge 'bubble' created by the solar wind that extends well beyond Pluto's orbit. The currently unexplored region spanning the outer corona and the inner heliosphere (the young solar wind) represents a fundamental gap in our understanding of the Sun-Earth connection. It is critical that we bridge this gap if we are ever to understand the Sun and heliosphere as a single system, or to understand the origin and nature of Earth-impacting structures. 

RAL Space involvement

RAL Space, the UK science lead for PUNCH, will provide the detector systems for four visible-light cameras, one hosted on each of the four suitcase-sized spacecraft, as well as performing calibration on the imagery once the mission has been launched.


Solar and heliospheric physics

Mission Objectives

To understand how coronal structures become the ambient solar wind.

  • How does the young solar wind flow and evolve on global scales?
  • Where and how do microstructures and turbulence form in the solar wind?
  • What are the evolving physical properties of the Alfven surface?

To understand the dynamic evolution of transient structures in the young solar wind.

  • How do coronal mass ejections (CMEs) propagate and evolve in the solar wind?
  • How do quasi-stationary corotating interaction regions (CIRs) form and evolve?
  • How do shocks for​m and interact with the solar wind across spatial scales?

​Launch Date


Main Partners

NASA, Southwest Research Institute (US, lead), Naval Research Laboratory (US)

Further Project Information