The newest addition to the National Oceanic and Atmospheric Administration’s (NOAA) weather-observing and environmental-monitoring satellite system is slated to launch from the Kennedy Space Center on March 1. The third satellite in the GOES-R+ series includes an instrument built by the Laboratory for Atmospheric and Space Physics (LASP) at CU Boulder that will serve as the nation’s “eyes” on the Sun.
The LASP extreme ultraviolet and x-ray irradiance sensors (EXIS) instrument will monitor for solar flares and energetic particle events that can disrupt technology on Earth such as communication and global positioning systems, cause power outages, and interfere with satellites. EXIS will help forecasters monitor and predict space weather to protect these assets.
The leader of the EXIS program is LASP senior scientist Frank Eparvier, who has been developing solar-monitoring instruments for many NASA missions throughout his 25-year career. He was instrumental in securing LASP’s involvement in the GOES program in 2006.
We caught up with Eparvier to learn more about the EXIS program and how his research has shed new light on the Sun’s impacts on Earth, as well as hear his insights regarding the recent loss of 40 Starlink satellites.
LASP: What inspired you to study space weather?
FE: One summer evening in 1983, as I was driving home from my late-night job working in a candle factory in Oshkosh, Wisconsin, I saw some weird lights in the sky. I pulled over into a pasture to watch the curtains and patches of green and red light, which are rarely seen in Wisconsin. I spent the next several hours watching the Northern Lights in awe. That night stuck with me through my college years—not just my appreciation of the beauty, but also my curiosity about the physics behind what I’d seen. When applying to graduate schools a few years later, I jumped at the opportunity to study what at that time was called solar-terrestrial interactions at CU Boulder. The rest is history!
LASP: How does space weather affect us on Earth?
FE: Many satellites and the space station fly through the upper parts of the atmosphere, so changes in the Sun’s extreme ultraviolet (EUV) radiation can cause changes in the environment in which they travel. Variability in solar radiation can disrupt communications and global positioning navigation and cause unplanned changes in satellite orbits due to increased drag. Energetic particle events can also cause damage to satellite electronics and to humans. Given how reliant our society has become on space-based technology, it has become increasingly critical to monitor the Sun’s threats to it.
LASP: What is LASP’s involvement with the GOES program?
FE: Researchers at LASP have been users of the GOES solar and space weather data since the beginning of the program in the mid-1970s. Our solar group has been at the cutting edge of building research satellite instruments that make the most accurate measurements of the output of light from the Sun (irradiance). So when the opportunity came to build the next generation of four solar EUV and X-Ray irradiance instruments for the GOES-R+ program, we jumped at the chance.
LASP: What does the EXIS instrument program and its science mean to you?
FE: EXIS is the continuation of the solar EUV measurements that LASP has prided itself on providing to the community. While EXIS’s primary purpose is to measure the current state of the Sun and allow for forecasts of potentially harmful space weather, it also provides measurements of important environmental parameters that affect all of us on Earth over long periods of time. Providing this continuity is extremely important in understanding solar variability and its impacts over a period of decades. We at LASP decided to build the EXIS instruments, not as a job or to make money, but because we wanted to see NOAA make the best possible measurements for now—and for decades to come.
LASP: How has your research shed light on solar influences?
FE: I learned early in my career that our understanding of what was going on at the interface between the Earth and space was hampered by our poor knowledge of the energy inputs to that region, in particular from the Sun. When I got the opportunity to work with a group at LASP that was making the world’s best measurements of the input of light energy to Earth’s upper atmosphere, I jumped at it. I’ve spent my career trying to improve our understanding of the sources and impacts of space weather.
LASP: Would a better prediction system have helped to save the Starlink satellites?
FE: No, an adequate detection system is already in place. I think there were several factors involved in the Starlink loss. One was underestimating the risk. The geomagnetic storms that caused the satellites to fall out of the sky were not, by any means, extreme events. But the storm still caused an atmospheric disturbance that increased the density of the air the satellites were flying through. This loss didn’t need to happen; the information to avoid it was available through the NOAA and NASA national space weather programs. I think the lesson is to not underestimate a geomagnetic storm.
LASP: What do you see as the future of space weather prediction?
FE: The future of space weather prediction is rapidly catching up to that of terrestrial weather in terms of our ability to make accurate nowcasts, like our weather maps provide us on a daily basis. This is a very exciting time to be a solar scientist!
Written by Aimee Merkel – LASP communication specialist