PUNCH News

PUNCH tracks space weather and the solar wind itself across the entire inner solar system. This preliminary movie marks the first time a complete halo CME has been tracked all the way across the inner solar system, to impact with Earth.

Although PUNCH is still finishing up commissioning, it is beginning to produce scientifically interesting data. This image is an example: while the complete data processing pipeline is still being refined, the instrument is producing data that reveal the breathtaking beauty of the solar corona and the detailed structure that is the subject of PUNCH science. This image of the corona, during the eruption of a large CME on 6/3/2025, shows the detailed, wispy structure of the background corona and the CME itself.

Downlinking data from space costs money. PUNCH generates a lot of data, which drives the cost of operations – so we do everything we can to reduce the size of each image. We can’t use “lossy” compression algorithms, since a lot of the PUNCH science lives in very faint fluctuations that would be discarded in compression. Coming out of the camera, each WFI image is 8 Megabytes (MB) of 16-bit values. Using JPEG-LS (a lossless algorithm) on the raw images would reduce them to about 3 MB each. But we can (and do) squeeze them further.

PUNCH images of space are now available for download from NASA’s Solar Data Analysis Center (SDAC), in scientific-grade FITS format with relevant pointing and spacecraft-status metadata included. The data are updated twice daily by SDAC from the Science Operation Center (SOC) servers at Southwest Research Institute (SwRI) in Boulder, Colorado – and will continue to update as data arrive from space and are processed by the SOC. The data are also being indexed by the Virtual Solar Observatory. The PUNCH website includes links to documentation for the data and for the mission. Many thanks to Marcus Hughes (PUNCH SOC Lead), Jack Ireland (SDAC Lead), and their teams for opening the taps.

Commissioning of the PUNCH instruments is ongoing. As part of that activity, we ran the first full-orbit NFI (Narrow Field Imager) science sequence on Sunday, April 27. NFI captured several images of the Moon passing by the Sun in the sky, as seen in this unfiltered “Level 0” image in the standard PUNCH pseudocolor palette. The new Moon appears full, because it is illuminated by Earthshine from the full Earth (as seen from the lunar surface). This image is useful to demonstrate that the Moon does not directly interfere with NFI’s primary science, as it is not bright enough to impact the existing pattern of glinting stray light.

There've been lots of stories about this week’s triple-conjunction smiley moon in the media. We happened to catch the conjunction during PUNCH commissioning, along with two other planets besides!

This beautiful, ghostly polarimetric rainbow reveals the direction and degree of polarization of the ghostly zodiacal light, in a preliminary data product from the WFI-2 spacecraft. On 18-April, WFI-2 executed its first polarimetric triplet imaging, collecting images through all three of its polarizers in succession. The polarimetric triplet image, expressed as RGB color channels, reveals the direction (via hue) and degree (via saturation) of polarization everywhere in the field of view all at once. WFI looks to one side of the Sun (marked with a star glyph). This image, made with Level 0 (uncalibrated) data direct from the WFI-2 camera, is consistent with existing results (Leinert et al. 1998) on the direction and degree of polarization of the zodiacal light. Stars appear white because they are mostly unpolarized compared to the 7% polarization of the zodiacal light. PUNCH uses a novel mathematical formalism (“MZP”, DeForest et al. 2022) to manipulate and background-subtract the polarimetric values from each of its four cameras. Chromatic treatment of coronal polarization was demonstrated at the 2023 total solar eclipse (Patel et al. 2023), highlighting the long-term synergy between ground- and space-based observations of the corona.

PUNCH opened the protective doors of its first two instruments, the Narrow Field Imager (NFI) and one of its three Wide Field Imagers (WFI-2) on 14-April. First-light images from WFI and NFI reveal that they are in focus, functioning nominally, and able to collect the deep field images needed for PUNCH science. The first image from WFI-2 is a spectacular view of approximately 40° of sky, including zodiacal light, several constellations, and various other astronomical objects. The first image from NFI reveals in-focus performance and resolution of the faint starfield close to the Sun. These two images are composited here to show how the instruments’ data will fit together once commissioning is finished.

During the week of 2025 April 7, PUNCH collected calibration data from the instruments – our last chance to take advantage of closed doors, before they open. Even these “dark frames”, taken with the doors closed, are interesting to look at. These images are “Level 0” (unprocessed) data products generated by the Science Operations Center (SOC), with full flight metadata attached. The cameras are working properly, with low noise levels. The images are brighter on the right because PUNCH uses dual readout detectors, with separate digitizers for the two halves of the images; they have slightly different zero points, an effect we remove at “Level 1” and higher. There is a very small amount of light visible in the upper left, which we believe is stray light scattered by the closed instrument door itself. Over the South Atlantic Anomaly in Earth’s magnetic field, an area of enhanced cosmic ray flux, we see significant particle impacts on the detector. The rate of impacts agrees with calculations performed over six years ago, during the mission’s Phase A concept study.

PUNCH will maintain the constellation with a novel, water-powered, shot-glass-sized rocket engine attached to each spacecraft. Each spacecraft carries about a British pint (600 g) of water in a small canister. To run the engine, PUNCH electrolyzes about 1/10 tsp (0.5 mL) of water, building up small stores of hydrogen and oxygen at about 200 psi. Then it burns the fuel in just a few seconds. Each cycle delivers a “kick” of about one inch/sec (2 cm/sec): just enough to correct for small orbital shifts and keep the constellation stable. PUNCH is the first space mission to use this type of engine, which carries safe propellant but is complex to operate.

On March 29, 2025, many folks went outside to catch a glimpse of the partially eclipsed Sun, as the Earth carried them through the Moon’s shadow. PUNCH, orbiting high overhead, also passed through the shadow. Orbital velocities are high, so each spacecraft passed through the darkest part of the partial eclipse (the Moon’s penumbra) at a slightly different time, about eight minutes apart. Even though the instruments’ doors are still closed for commissioning, PUNCH registered the eclipse. During the brief interval of darkest shadow, the solar arrays couldn’t keep up with on-board power usage and each spacecraft briefly switched to battery power, using slightly less than 1% of its battery capacity to keep operating normally through the brief gap.

While making its unique observations, PUNCH will augment a fleet of international spacecraft observing the Sun and solar system, including NASA's Parker Solar Probe and STEREO missions, the European Space Agency's (ESA) Solar Orbiter and Jupiter Icy Moon Explorer (JUICE) missions, and the ESA/Japanese Space Agency's (JAXA) BepiColombo mission, all of which afford unique joint science opportunities. The longitudinal trajectories of these missions are shown along with the orbits of Mercury, Venus, and Mars relative to an Earth-stationary frame of reference. On this scale, PUNCH is always located at Earth. Trajectories were generated by the Austrian Space Weather Office / GeoSphere Austria (Möstl/Davies/Weiler) – further details and additional movies available.

The Science Operations Center (SOC) for PUNCH received the first data packets from the four spacecraft. The data downlinks included both engineering and test image packets. The SOC successfully decompressed the packets and reconstructed the expected striped test pattern image. Using a test pattern allows the SOC to verify that data is properly transmitted and formed into images. The spacecraft sends engineering packets down alongside the images that indicate spacecraft parameters such as orientation and position. The SOC’s automated processing routines ingested this data and confirmed the spacecraft are pointing toward the Sun as expected. A good estimate of the spacecraft pointing is critical for the SOC’s data processing; it would not be possible to construct the seamless mosaics required to answer PUNCH’s science questions without it. The next step is to collect and process calibration images without light on the sensor, commonly called dark images. More information about the SOC processing can be found on GitHub.

The heliophysics community came out to celebrate the impending launch by presenting and discussing the latest developments in PUNCH science, including the origin and evolution of the ambient solar wind and turbulence within it, and the physics, tracking and predictability of transient events such as coronal mass ejections, corotating interaction regions, and shocks. Beyond these primary PUNCH science topics, the workshop provided a forum for exploring PUNCH connections to the magnetosphere and aurora, zodiacal dust, and sun-grazing comets and other solar system objects. PUNCH's readiness to engage scientists around the world was demonstrated through presentations and a hands-on tutorial on data access, and its synergies with a range of community missions and models explored through panel discussions. The meeting took place February 25th and 26th, 2025 at Cal Poly in San Luis Obispo, CA, and benefited from the support and involvement of Cal Poly students and faculty. It was further enriched by PUNCH outreach events before and during the meeting.

We invite the community to the sixth PUNCH (Polarimeter to UNify the Corona and Heliosphere) Science Meeting on February 25th and 26th, 2025 at Cal Poly in San Luis Obispo, CA. Major science topics include the origin and evolution of the ambient solar wind and turbulence within it and the physics, tracking, and predictability of transient events including CMEs, CIRs, and shocks.

We invited the community to the fifth PUNCH (Polarimeter to UNify the Corona and Heliosphere) Science Meeting (June 20-21, 2024) in Boulder, Colorado. Major science topics included the origin and evolution of the ambient solar wind and turbulence within it and the physics, tracking, and predictability of transient events including CMEs, CIRs, and shocks.

The topic of this telecon was in-situ/remote-sensing/modeling synergies. Click to go to meeting page with links to presentations.

The fourth PUNCH (Polarimeter to UNify the Corona and Heliosphere) Science Meeting was successfully held in the summer of 2023 in Boulder, CO. We solicited abstracts for poster/oral presentations from the community on subjects related to this topic. Click to go to meeting page with links to presentations and posters.

The topic of this telecon was synergies with other missions/projects. Click to go to meeting page with links to presentations.

The third PUNCH (Polarimeter to UNify the Corona and Heliosphere) Science Meeting was on August 12th, 2022. Attendance was high and the attendees were highly engaged. Major science topics included the origin and evolution of the ambient solar wind and turbulence within it, mission outreach, and the physics, tracking, and predictability of transient events including CMEs, CIRs, and shocks.

PUNCH science and outreach development continues, with presentations at the Fall 2021 AGU. PDFs of posters are available on the PUNCH publications / presentation page, and videos of talks on the PUNCH Youtube Playlist.

The PUNCH 2 Science Meeting took place August 9-11, 2021. If you missed the talks, or just want to see them again, they are available via a Youtube Playlist, and also through the workshop agenda with time-stamped access to specific talks.

PUNCH 2 Science Meeting First Announcement (March 31, 2021) We invite the community to the second PUNCH (Polarimeter to UNify the Corona and Heliosphere) Science Meeting (August 9-11, 2021), an in-development NASA mission that will image the outer corona and solar wind throughout the inner heliosphere. Major science topics include origin and evolution of the ambient solar wind and turbulence within it, and the physics and predictability of transient events including CMEs, CIRs, and shocks.

PUNCH has instituted a program to recognize and encourage early-career scientists working with the Science Team on problems that support and enhance PUNCH mission science. PUNCH Associate Investigators (AIs) pursue science projects with mentorship from PUNCH co-I(s), attend team meetings, participate in PUNCH working group activities, and present at PUNCH science meetings. They act as liaisons, communicating PUNCH science to the broader community and community needs back to the project. In this way, they help grow the PUNCH user base, and also benefit from the career-enriching experience of being embedded in a NASA mission at an early stage of their careers.

PUNCH, the Polarimeter to UNify the Corona and Heliosphere, is an in-development NASA mission that will image the outer corona and solar wind throughout the inner heliosphere. Major science topics include origin and evolution of the ambient solar wind and turbulence within it, and the physics and predictability of transient events including CMEs, CIRs, and shocks.

The first PUNCH Science Team meeting was held virtually June 3-5, 2020. 44 team members and colleagues attended, sharing information about the mission, instruments, science goals, and planned data products. We also learned about STEAM, our student enhancement option, and plans for PUNCH Outreach. The Outreach presentation included a member of the Hopi tribe who read aloud his letter of support for our envisioned plan. There are many Science Team members who are experienced and interested in contributing to Outreach and Communications for PUNCH.