As part of NASA’s Artemis campaign, a cutting-edge X-ray imager, the Lunar Environment Heliospheric X-ray Imager (LEXI), is heading to the Moon to capture the first global images of Earth’s magnetic field, which protects our planet from harmful solar radiation. LEXI is one of 10 scientific payloads onboard the upcoming lunar mission, set to launch from Kennedy Space Center in Florida no earlier than mid-January. The payload will ride aboard Firefly Aerospace’s Blue Ghost Lander under NASA’s Commercial Lunar Payload Services (CLPS) initiative.
LEXI’s primary mission is to support NASA’s understanding of how Earth’s magnetosphere—its magnetic shield—responds to space weather, which is driven by solar activity. By taking detailed X-ray images of this protective barrier, the instrument will provide insights into the dynamic processes that shape our planet’s interaction with the solar wind and other cosmic forces.
Once LEXI lands on the Moon and stabilizes, it will power up, warm up, and begin its work: observing Earth’s magnetosphere from the unique vantage point of the lunar surface. For six days, the instrument will capture low-energy X-rays produced when solar wind particles collide with Earth’s magnetic field at the edge of the magnetosphere, a region known as the magnetopause. These X-rays are produced as the solar wind impacts the magnetosphere, and LEXI’s global field of view will allow researchers to observe the full scope of this interaction for the first time.
“Unlike past missions that have only observed patchy segments of the magnetopause, LEXI will provide a comprehensive view of the entire region,” explained Brian Walsh, a space physicist at Boston University and principal investigator for LEXI. “We’re trying to get the big picture of Earth’s space environment—this will be science you can actually see.”
As the solar wind changes in strength, it causes fluctuations in the size and shape of Earth’s magnetosphere. During periods of strong solar wind, the magnetosphere compresses and contracts toward Earth, while it expands when the wind weakens. LEXI will provide critical data on this “breathing” effect, offering a new understanding of how the magnetosphere reacts to varying solar conditions.
“We expect to see the magnetosphere ‘breathing’ in and out for the first time,” said Hyunju Connor, an astrophysicist at NASA’s Goddard Space Flight Center and LEXI’s NASA lead. “When the solar wind is particularly strong, the magnetosphere will shrink and push back toward Earth, while it will expand when the solar wind weakens.”
This real-time data will allow the research team to observe how the magnetosphere evolves over time, offering a deeper understanding of the boundary that protects Earth from solar radiation.
In addition to monitoring the magnetosphere, LEXI will also capture magnetic reconnection events. This process occurs when the magnetosphere’s magnetic field lines merge with those of the solar wind, releasing energetic particles that can rain down on Earth’s poles, creating auroras. Understanding these reconnection events is a key area of research, as scientists are still working to understand how often they occur, whether they happen at multiple locations simultaneously, and whether they occur in steady flows or burst-like patterns.
The data gathered by LEXI could provide answers to these long-standing questions, shedding light on how the solar wind impacts Earth’s atmosphere and space weather.
While these solar particles can create beautiful auroras, they also pose risks to satellites and power grids. Solar storms and magnetic reconnection events can damage satellite electronics and disrupt communications, navigation, and even power infrastructure on Earth. By understanding these processes, scientists hope to develop strategies to better protect critical infrastructure from space weather events.
“We want to understand how nature behaves,” said Connor. “By understanding the magnetosphere’s interactions with the solar wind, we can help protect our infrastructure in space and on the ground.”
This lunar mission will not be LEXI’s first foray into space. Originally developed as STORM (Suborbital X-ray Imaging Spectrometer), the instrument was designed to test technology for detecting low-energy X-rays over a wide field of view. In 2012, the STORM instrument launched aboard a sounding rocket, collected X-ray images, and successfully returned to Earth. With its proven capabilities and new enhancements, LEXI is now poised for its ambitious mission on the Moon.
As part of NASA’s Artemis program, LEXI’s findings will help provide crucial insights into Earth’s space environment and contribute to the development of strategies to protect humanity from the potentially harmful effects of space weather.
By Impact Lab