Using continuous imagery from NASA’s PUNCH (Polarimeter to Unify the Corona and Heliosphere) mission, scientists predicted the near-Earth arrival of a solar eruption to within 30 minutes in an initial proof of concept test. The results, presented Tuesday at the Committee on Space Research Scientific Meeting and under review at the journal Space Weather, could revolutionize the way Earth-impacting storms are forecasted.
“We thought PUNCH would be good at this, but it’s a stunning result,” said Craig DeForest, principal investigator for PUNCH at Southwest Research Institute’s Solar System Science and Exploration Division in Boulder, Colorado. “To put it in perspective, this could be the space weather equivalent of going from a steam engine to a modern internal combustion engine.”
Solar storms are caused by huge explosions of material off the Sun called coronal mass ejections. Forecasting when the ejections will reach Earth is key for mitigating their impacts on power grids, satellites, and astronauts. However, until recently, coronal mass ejections could not continuously be tracked for much of their journey across the solar system.
That changed in 2025 with the launch of the PUNCH mission, which uses four spacecraft in low Earth orbit to make continuous 3D observations of the inner solar system. Before PUNCH, coronal mass ejections could only be seen as they traversed one-fifth the way from the Sun to Earth, leaving scientists to guess what happened over the rest of the distance. With PUNCH’s wider field-of-view, scientists can now routinely track the solar explosions nearly all the way to Earth, capturing a new image every four minutes.
Scientists used data from a coronal mass ejection that left the Sun on May 31, 2025, to retroactively test if they could improve forecast modeling. Scientists input the images into a computer model, which analyzed the leading edge of the coronal mass ejection over time. As it moved and evolved across the inner solar system, the model used the coronal mass ejection’s speed and geometry to calculate when it would reach Earth.
Twelve hours after the coronal mass ejection left the Sun, the model settled on a final prediction showing the storm would arrive eight hours later. That predicted arrival time was ultimately accurate to within a half hour, making it 10 times better than currently used methods, which only provide a 5-hour window. In addition, the model itself revealed when the estimate had stabilized, so that a space weather forecaster would be able to predict the arrival time with confidence.
“We accomplished an order of magnitude better result than the state-of-the-art method with a really basic process, just informed by the fact that the coronal mass ejection could be tracked continuously across the solar system,” DeForest said.
These first results demonstrate the power of PUNCH’s wide-field imagery to track the solar events as they travel out from the Sun. Ultimately, the scientists think that with more refined PUNCH data and better models, they could be able to forecast coronal mass ejection arrival times even further in advance.
Beyond space weather forecasting, the images also help scientists glean new insights on coronal mass ejections. The high-resolution images allowed the scientists to see new structures in coronal mass ejections, revealing that the clouds of material are clumpier than previously thought and continue to evolve as they cross the solar system.
The PUNCH data is also helping scientists better understand how plasma, the solar material launched by coronal mass ejections, moves across space. This information can help astrophysicists better understand plasma’s behavior across the galaxy, such as in star-forming regions where it is nearly impossible to study on small scales.
Southwest Research Institute, based in San Antonio, leads the PUNCH mission and operates the mission’s four spacecraft from its facilities in Boulder. The mission is managed by Space Science Mission Operations at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, for the Science Mission Directorate at the agency’s headquarters in Washington.
By Mara Johnson-Groh
NASA’s Goddard Space Flight Center, Greenbelt, Md.
