PUNCH, a NASA Small Explorer (SMEX) mission, is poised to deepen our understanding of the Sun's corona, the outer atmosphere visible during total solar eclipses, and its intricate relationship with the solar wind that fills and defines our solar system. The mission's significance lies in its potential to unify these two critical aspects of solar physics, enhancing our grasp of the Sun's influence on the solar system.

"This was an internal review, but it is a huge milestone for us," said PUNCH Principal Investigator Dr. Craig DeForest of SwRI's Solar System Science and Exploration Division. "It marks the transition from assembling subsystems to integrating complete observatories that are ready to launch into space."

The mission is designed as a constellation of four small, suitcase-sized satellites that will be launched into a polar orbit formation. Among these, one satellite will be equipped with a coronagraph, the Narrow Field Imager, dedicated to continuous imaging of the Sun's corona. The remaining three satellites will each carry Wide Field Imagers (WFIs), developed by SwRI, optimized for imaging the solar wind. Together, these instruments will create a field of view expansive enough to cover a quarter of the sky, centered on the Sun.

In an exciting development for educational collaboration, PUNCH also includes a student-built instrument, the Student Energetic Activity Monitor (STEAM). This spectrometer will capture the X-ray spectrum of the Sun, providing valuable data to better understand corona heating and the initial acceleration of the solar wind from the Sun's surface.

"Just as in astronomy when a new telescope like Hubble opens a new window to the universe, PUNCH's four satellites are going to visualize a mysterious process, imaging how the solar corona transitions into the solar wind," explained Dr. James L. Burch, senior vice president of SwRI's Space Sector. "As an authority in heliophysics research, SwRI is not only leading the science of this mission but also building the spacecraft and three of the four sensors designed to let us see, for the first time, the birth of the solar wind."

The first three PUNCH instruments have already arrived at SwRI's new Spacecraft and Payload Processing Facility for integration. These include the Narrow Field Imager from the Naval Research Laboratory and the STEAM X-ray spectrometer instrument from the Colorado Space Grant Consortium. Additionally, the first of the three Wide Field Imagers has been delivered, with the remaining two in the final stages of integration and testing.

"The team really came together and completed a tremendous amount of verification work to get us ready for this review," said PUNCH Project Manager Ronnie Killough. "This work will pay huge dividends as we prepare for our next major milestone, the pre-environmental review in early 2024. That will clear the observatories for a battery of tests prior to spaceflight."

The SMEX program, under which PUNCH is categorized, offers frequent flight opportunities for world-class scientific investigations in heliophysics and astrophysics, utilizing innovative and efficient approaches. SwRI's role extends beyond leading the science mission, as it will also operate the four spacecraft. Collaborating with SwRI, the U.S. Naval Research Laboratory is developing the Narrow Field Imager, while RAL Space in Oxfordshire, England, is providing detector systems for the four visible-light cameras.

Related Links
Heliophysics at Southwest Research Institute
Solar Science News at SpaceDaily