NASA’s four PUNCH spacecraft (Polarimeter to Unify the Corona and Heliosphere) designed to study the Sun’s corona and solar wind have finally arrived at Vandenberg Space Force Base, where they will undergo final preparations before launching into space.
Designed by the Southwest Research Institute (SwRI), the four PUNCH spacecraft will hitch a ride to space alongside NASA’s Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer (SPHEREx) mission. The first launch target date is the end of February.
“The PUNCH mission will integrate our understanding of the Sun’s corona, the outer atmosphere visible during total solar eclipses, with the ‘solar wind’ that fills and defines the solar system,” explained PUNCH Principal Investigator, Dr. Craig DeForest of SwRI’s Solar System Science and Exploration Division, in a statement. “Once the constellation is deployed, we’ll be able to routinely see and understand the solar wind itself, as it streams out from our star and washes over Earth.”
PUNCH Spacecraft Will Alwyas Remain in Sunight
According to mission planners, after the four PUNCH spacecraft are launched into space, they will be placed into a polar orbit “along the day-night line.” This location will ensure that the PUNCH constellation always remains in sunlight and that all four spacecraft maintain a clear view in all directions.
Three of the mission satellites are equipped with customized Wide-Field Imagers designed by the SwRI team. These instruments provide mission scientists with views of 18 to 180 solar radii, or 45 degrees “away from the Sun.” The instruments also employ an artificial horizon and a set of deep baffles to offer an unprecedented view of the “very faint outermost portion” of the Sun’s corona and solar wind.
“The instrument reduces direct sunlight by over 16 orders of magnitude or a factor of 10 million billion — the ratio between the mass of a human and the mass of a cold virus,” DeForest said. “The wide-field achromatic optics are based on the famous Nagler eyepiece design used in terrestrial telescopes.”
The fourth and final satellite in NASA’s PUNCH spacecraft constellation is equipped with a Narrow Field Imager (NFI) developed by the U.S. Naval Research Lab. This instrument allows mission scientists an uninterrupted view of the Sun’s corona.
Notably, all four satellites on the constellation are equipped with a specialized digital camera that will capture three different digital images through three specialized filters every four minutes. These same cameras will generate one polarized digital image every eight minutes to help keep the overall OUNCH constellation calibrated. This is critical, mission planners say, as the four satellites are designed to operate as “a single virtual instrument” that can capture roughly a quarter of the sky centered on the Sun.
“When electron particles scatter sunlight, the waves of light become aligned in a particular way — this is polarized light,” DeForest said. “By measuring the light using polarizing filters similar to polarized sunglasses, PUNCH scientists can make a 3D map of the features they see throughout the corona and inner solar system.”
Understanding the Solar Wind is Critical for Future Space Missions
Understanding the solar wind and the activity of the Sun’s corona has become increasingly critical as Coronal Mass Ejections (CMEs) and other solar events can directly affect satellites and other spacecraft in Earth’s orbit. The SwRI team hopes that NASA’s PUNCH spacecraft will help improve our understanding of the Sun’s phases so mission planners can better prepare future spacecraft and satellites for the effects caused by the solar wind and CMEs.
“The PUNCH team proved to be remarkably resilient as we successfully overcame a number of late-breaking challenges over the last several months to complete integration and environmental testing of the four observatories,” said PUNCH Project Manager Ronnie Killough. “I look forward to a successful launch!”
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.