NASA’s Lunar Environment Heliospheric X-ray Image (LEXI) imager, which will use X-ray vision to measure the Earth’s magnetosphere from the moon’s surface, is scheduled for launch aboard Firefly Aerospace’s Blue Ghost Lander no earlier than mid-January.
Designed by scientists at Boston University as part of the Artemis mission that will return humans to the moon, LEXI will offer insights into how space weather driven by the sun affects Earth to help mission planners protect future spacecraft from the harmful effects of solar radiation.
According to a statement from NASA, the LEXI instrument will wait until the “dust clears” from its lunar landing before firing up its X-ray imager. The instrument will be pointed at Earth for six days while it gathers images of the X-rays that emanate from the magnetosphere.
If successful, the mission could inform mission planners on the dynamics of the magnetosphere, which protects the planet from radiation. The data could also offer an unprecedented view of how the magnetosphere can open up to allow streams of solar particles through, resulting in auroras and potentially damaging infrastructure.
“We’re trying to get this big picture of Earth’s space environment,” said Brian Walsh, a space physicist at Boston University and LEXI’s principal investigator. “A lot of physics can be esoteric or difficult to follow without years of specific training, but this will be science that you can see.”
NASA’s LEXI Will Capture Images of the Magnetosphere “Breathing”
Before LEXI, several satellites measured the X-rays ejected by the magnetosphere after collisions with solar particles. Still, those readings only captured small segments of the magnetosphere’s outer edge, the magnetopause, where these events occur. With LEXI settled on the Moon’s surface, it will be the first instrument capable of seeing the entire magnetopause and the x-rays ejected from it at the same time. The result will be the first-ever real-time measurement of the magnetosphere “breathing in and out” as it expands and contracts in reaction to the flow of solar particles.
“We expect to see the magnetosphere breathing out and breathing in for the first time,” said Hyunju Connor, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and the NASA lead for LEXI. “When the solar wind is very strong, the magnetosphere will shrink and push backward toward Earth, and then expand when the solar wind weakens.”
The NASA team that will monitor the data from LEXI once it has landed says it will also potentially capture an event known as “magnetic reconnection.” According to mission planners, magnetic reconnection is when the magnetosphere’s field lines merge with similar field lines in the solar wind and “release energetic particles that rain down on Earth’s poles.” Those readings could help answer longstanding questions about these events, including whether they occur steadily or in compacted bursts. The data will also help answer whether these events happen at multiple sites simultaneously.
“We want to understand how nature behaves,” Connor said, “and by understanding this, we can help protect our infrastructure in space.”
After a Previous Life as STORM, X-ray Imager is Reborn
Notably, NASA says this is not LEXI’s first voyage into space. Originally called STORM, the instrument was built in 2012 to test the ability to measure low-power X-rays over an extended field of view. After its successful launch later that year, the instrument performed its data collection and then fell back to Earth.
Since the instrument’s successful mission, it has resided in a display case at NASA’s Goddard Space Flight Center. According to Walsh, the idea to reuse STORM and rename it LEXI came about after NASA asked participants in the Commercial Lunar Payload Services (CLPS) umbrella program, which includes Artemis, to search for low-cost missions that could return significant scientific value without a high cost.
“We’d break the glass — not literally — but remove it, restore it, and refurbish it, and that would allow us to look back and get this global picture that we’ve never had before,” he said.
The team found that the instrument was in overall good shape, but some of the optics and other components were replaced with newer technologies. Given a second life as LEXI, the X-ray imager is now ready for launch. According to mission planners, it could generate significant scientific value once again.
“There’s a lot of really rich science we can get from this,” Walsh said.
NASA offers more insight into LEXI, ARTEMIS, and the CLPS program on its mission website.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.