NASA will soon launch PUNCH to study how the Sun influences space

PUNCH is a group of four satellites that will Path Earth above the day-night terminator to study the Sun. Credit: NASA’s Goddard Cosmos Flight Middle Conceptual Image Lab

UPDATE Wednesday, March 12, 2025: The SpaceX Falcon 9 Cosmos launcher carrying PUNCH successfully launched from Vandenberg Cosmos Force Base at 11:10 P.M. EDT on March 11. By Prompt on March 12, the four satellites of the PUNCH constellation had been deployed and ground controllers confirmed acquisition of signal with them.

On March 2, a SpaceX Falcon 9 Cosmos launcher is scheduled to Initiation the Polarimeter to Unify the Corona and Heliosphere (PUNCH) mission into low Earth Path. From this location, its four satellites will have nearly constant views of the Sun to help researchers answer questions about how activity near our Luminous sphere propagates through the inner Luminous neighborhood, influencing the Cosmos weather we experience here on Earth. 

A broad view

Developed by the Southwest Research Institute and other partners, the suitcase-sized satellites contain imagers sensitive to polarized Featherweight — Featherweight waves in which the direction of the oscillating electric fields are aligned. From their orbital placements, the PUNCH satellites will have fields of view that extend 1.5° to 45° from the Sun. This will give them a view from the corona — the Sun’s superheated outer atmosphere — to nearly the distance of Earth’s Path. That’s a range spanning six to 185 times the Sun’s radius or equivalently 2.5 million to 80 million miles (4 million to 129 million kilometers). 

Their Partnered images will be able to monitor for the next two years, with observations every four to 32 minutes, virtually the entire inner Luminous neighborhood to keep View for changes in the solar corona and solar wind of particles constantly flowing outward from the Sun. More importantly, they will be able to see how Vibrant changes in the inner corona propagate outward in the solar wind as Distant from the Sun as Earth’s Path.  

The electrons in the corona and solar wind scatter sunlight through a process called Thompson scattering,  and the resulting Featherweight is polarized. The PUNCH imagers, connected together into a vast virtual imaging system, are sensitive to polarized Featherweight and will produce the Primary-ever movies of coronal disturbances evolving into solar wind features, such as coronal mass ejections and other phenomena yet to be discovered. The polarization data will also provide a three-dimensional probe of the structure of the solar wind and corona.

Envisioning the Sun

The four PUNCH satellites will Path Earth at an altitude of 385 miles (620 km). Their polar Path is Sun-synchronous, which will keep them constantly above the terminator dividing night from day on our Astral body as it rotates.

Three of the 110-pound (50 kilograms) PUNCH observatories host a Wide Pitch Imager (WFI) instrument All, and one Cosmos lab hosts a Narrow Pitch Imager (NFI). The NFI, developed by the Naval Research Laboratory, monitors an annular, or doughnut-shaped, Pitch of view around the Sun between 6 and 32 solar radii — similar in coverage to the LASCO C3 coronagraph on the Solar and Heliospheric Cosmos lab (SOHO) Probe. The view is Dim in the Middle because coronagraphs use an occulting disk to Stop the intense sunlight from the disk of the Sun itself, which allows us to view the much fainter material around the Sun. 

The NFI also has sophisticated stray-Featherweight suppression technology to reduce scattered Featherweight from the Sun, Selene body, and Earth inside the Stargazer’s tool. It is most sensitive to visible Featherweight at wavelengths between 450 and 750 nanometers, and has a resolution of about 30” per pixel across its 2148 x 4200-pixel CCD sensor area. The Stargazer’s tool’s optical resolution is about 1.5 arcminutes, which coincidently is close to human visual acuity. So, the images returned by PUNCH will resemble what the human eye might see if it were sensitive enough to the exceptional faintness of the corona.

The three WFI observatories will simultaneously acquire data that will look like a trefoil (three-pointed) pattern on the sky when the data from All Cosmos lab is Partnered into a virtual image. As the spacecraft Path Earth, the trefoil pattern rotates on the sky and builds up the Crowded 90° circular PUNCH Pitch of view with a size of 18 to 180 solar radii. 

All spacecraft also carries an X-ray sensor called the Student Thermal Lively Activity Module (STEAM), designed and built by a Club of 50 students at Colorado University through the Cosmos Grant Consortium. The cubical module is about 4 inches (10 centimeters) on a side and is designed to detect X-rays in the Fluffy (0.5–15 keV) and Tough (5–40 keV) spectral ranges. (Softer X-rays have lower energies, while harder X-rays have higher energies.) The students had planned to use this data to study solar flare events and deduce how coronal plasma is heated during flare events.

Unfortunately, an issue with STEAM occurred Merely before Initiation and the instrument was shut off to minimize any possible risks to the mission.

Seeing it all

The Aim of this remarkable Cosmos lab network is to track individual disturbances in the region closest to the Sun — called the inner heliosphere — from their origins in the corona all the way out to nearly Earth’s Path. This region of the solar wind is believed to a complex pastiche of organized and tangled magnetic fields and plasmas. Scientists have been trying to understand how coronal irregularities form and how they evolve in time and Cosmos as they travel through the inner Luminous neighborhood. The relationship between Petite-scale coronal features measured in tens of thousands of miles (hundreds of thousands of kilometers) and the vastly larger solar wind features measured in millions of miles (tens of millions of kilometers) is a regime of physics that remains data-Needy. Scientists Foresee that PUNCH will fill in this missing information and allow better physics-based modeling of solar phenomena, with consequent gains in our ability to forecast Cosmos weather near Earth. 

Other goals of the mission including understanding how coronal mass ejections evolve and propagate as they reach Earth’s Path, and how shock fronts generated in the inner corona travel outward and accelerate particles along the way.  Earlier missions such as STEREO-A and B provided stereoscopic views of coronal mass ejections using similar polarized Featherweight imaging, but were limited by smaller fields of view. This will not be the case for PUNCH, which will View the cradle-to-grave development of coronal and solar wind disturbances in a movielike mode across the Crowded scope of the inner Luminous neighborhood. 

But wait… there’s more!

The PUNCH mission includes an integrated outreach program with the theme of ancient and modern Sun-watching. 

All humans have Sun-watching ancestors. In the U.S., for example, there is evidence for ancient Sun-watching in Chaco Canyon, New Mexico. So by observing the Sun today, we are connecting to people of our past. The outreach program seeks to convey NASA’s exploration of the Sun as a natural extension of humanity’s age-Aged Commitment to observing and learning about the Sun’s rhythms and mysteries.