October 2, 2023 — NASA has selected a new SwRI-managed heliophysics mission focused on investigating the Sun’s middle corona — an enigmatic region of the Sun’s atmosphere driving solar activity — for a Phase A, mission definition study. Southwest Research Institute’s Dr. Dan Seaton is deputy principal investigator of the Center for Astrophysics | Harvard & Smithsonian-led EUV CME and Coronal Connectivity Observatory (ECCCO), bringing SwRI’s expertise in heliophysics, project management and systems engineering as well as mission and science operations to the proposed small explorer mission.
“ECCCO will answer fundamental questions about the origins of the mass and energy flow that link the Sun to the outer corona and overall heliosphere, the ‘bubble’ of space encompassing the solar system ‘inflated’ by the solar wind,” said Dr. Kathy Reeves, ECCCO principal investigator from the Center for Astrophysics | Harvard & Smithsonian (CfA). “We’ll have unique data that have the potenential to reveal the deep connection between the Sun and its larger environment in the heliosphere.”
The mission focuses on imaging and spectroscopy of the middle corona in extreme ultraviolet (EUV) wavelengths, tracking events like coronal mass ejections (CMEs) from their origins until they leave the Sun. CMEs are huge bursts of coronal plasma threaded with intense magnetic fields ejected from the Sun over the course of several hours. CMEs reaching Earth can generate geomagnetic storms and cause anomalies in and disruptions to modern conveniences such as electronic grids and GPS systems.
“We’ve explored the Sun itself extensively over the last few decades,” said Seaton, a heliophysicist who specializes in imaging the Sun. “With SwRI’s upcoming PUNCH mission, we’ll explore the outer corona and heliosphere, but the middle corona remains a great mystery. ECCCO will finally reveal its secrets.”
NASA’s Polarimeter to Unify the Corona and Heliosphere (PUNCH) mission, scheduled to launch in 2025, is designed to better understand how the mass and energy of the Sun’s corona become the solar wind that fills the solar system. The complementary ECCCO mission would detect, track and measure CME and solar wind outflows from, and study changes in the large-scale structure of, the corona on timescales ranging from minutes to months and years.
“ECCCO is a fascinating mission. The science is right at the center of solar physics right now, going after the ‘middle corona’ that regulates the structure of the corona and the solar wind. Its instruments and analysis build on decades of advances in data processing,” said SwRI’s Dr. Craig DeForest, principal investigator of the PUNCH mission and an ECCCO co-investigator. “We’ve had prototypes of this kind of spectral imaging data — ‘overlappograms’ — since Skylab in the 1970s. Only now do we have the technology to sort out all the information in them.”
ECCCO’s innovative high-sensitivity instruments, when trained on the middle corona, will return wide-field data that are critical to understanding eruptive events and solar wind streams. The ECCCO-I imager sees the full multi-thermal corona from the surface of the Sun out to three solar radii away from the star. The twin ECCCO-S spectrographs are designed to provide unprecedented temperature and density diagnostics from the solar disk to the middle corona.
“This project brings together a team with decades of experience building this kind of instrumentation at CfA, a really strong science team from around the United States, and SwRI’s mission development and engineering expertise to produce a mission that will make the most unique and exciting observations of the solar corona we’ve ever had,” Seaton said.
CfA will lead the ECCCO science mission, SwRI will manage the project and its science and mission operations centers, and Ball Aerospace will build the spacecraft. NASA’s Explorers Program provides frequent flight opportunities for world-class scientific investigations from space utilizing innovative, streamlined and efficient management approaches.