NASA's PUNCH mission is about to launch, using a network of four small satellites to study the corona and solar wind. By acting as a single large instrument, these spacecraft will provide a clearer three-dimensional view of solar storms and space weather. This innovation will revolutionize the way we predict and respond to space weather events that affect Earth.


NASA's PUNCH mission will use four suitcase-sized satellites, designed and built by SwRI, distributed around the Earth and synchronized as a single "virtual" instrument 8,000 miles across. Illustrations not to scale. Source: Southwest Research Institute

Four small spacecraft, each about the size of a suitcase, will launch from Vandenberg Air Force Base in California by February 28. The spacecraft are designed and built by Southwest Research Institute (SwRI) in San Antonio as part of NASA's Unified Coronal and Heliospheric Polar Instrument (PUNCH) mission. They will fly into space with NASA's Spectrophotometer for the History of the Universe, Epoch of Reionization and Ice Explorer (SPHEREx) observatories.

"The PUNCH mission will study the corona, the Sun's outer atmosphere, and the solar wind, which as a unified, integrated system populate and define our solar system," said PUNCH principal investigator Dr. Craig DeForest of SwRI's Solar System Science and Exploration Division in Boulder, Colorado. "This has not been possible before because we use different kinds of instruments to characterize these regions. PUNCH will integrate our understanding of the role of the corona in heating and accelerating the solar wind that washes over Earth and other planets in the solar system."

The four PUNCH satellites, designed and built by SwRI, will provide a 90-degree portrait of the sky centered on the sun, as shown here. A narrow-field imager on a satellite is a coronagraph, which blocks the Sun's brightest light to reveal the darker corona. Three widefield imagers developed by the Southwest Research Institute use baffles and ground processing techniques to reveal faint traces of the outer corona and the solar wind itself, which is 1,000 times dimmer than the Milky Way. Source: Southwest Research Institute

After launch, the PUNCH satellite constellation will be deployed in low-Earth orbit along the day-night line, so the spacecraft will always be in sunlight and can clearly see in all directions.

"To get the data we need, we have to build an instrument as big as the Earth," DeForest said. "That was impossible, so we used four small spacecraft that were synchronized around the Earth to create a virtual instrument 8,000 miles wide, centered on the Sun, imaging a quarter of the sky."

One satellite carries a coronagraph, a narrow-field imager developed by the U.S. Naval Research Laboratory that continuously images the solar corona. The other three satellites carry wide-field imagers developed by SwRI to observe the very faint outermost part of the corona and the solar wind itself.

"PUNCH will make the invisible visible," DeForest said. "The deep baffles in our wide-field imager reduce direct sunlight by 16 orders of magnitude or 1,000 trillion times - equivalent to the ratio of the mass of a human to the mass of a cold virus. State-of-the-art processing on the ground then removes the background starfield, or more than 99% of the light in each image, revealing the extremely faint glimmer of the solar wind."

Each spacecraft includes a camera developed by RALSpace that collects three raw images every four minutes through three different polarizing filters. In addition, each spacecraft will generate a clear, non-polarized image every eight minutes for calibration. This new perspective will allow scientists to discern the exact trajectory and speed of coronal mass ejections as they move through the inner solar system, improving current instruments that can only measure the corona itself and not its three-dimensional motion.

The four suitcase-sized spacecraft, designed and built by Southwest Research Institute in the United States, passed all final evaluations and are now loaded into the spacecraft, awaiting launch into low Earth orbit by February 28. NASA's PUNCH mission aims to provide the first unified, comprehensive image of the solar corona and nascent solar wind. Source: Southwest Research Institute

"While PUNCH is a research mission, we will be able to track space storms or coronal mass ejections in three dimensions as they approach Earth -- critical for forecasting space weather and how it may impact us as a spaceflight society," DeForest said. "We hope that PUNCH can revolutionize space weather forecasting in the same way that geostationary satellites have revolutionized weather forecasting on Earth."

NASA's Small Explorers (SMEX) program provides frequent opportunities for groundbreaking space science missions using innovative and cost-effective methods in heliophysics and astrophysics. As the lead agency for the PUNCH mission, Southwest Research Institute (SwRI) will also oversee the operations of the four spacecraft. The PUNCH team includes the U.S. Naval Research Laboratory, which developed the narrow-field imager, and RALSpace, a company in Oxfordshire, England, which provides the detector system for the mission's four visible-light cameras.

Compiled from /ScitechDaily