NASA’s LEXI provides X-ray vision of Earth’s magnetosphere

NASA’s X-ray imager will head to the moon as part of the agency’s Artemis campaign, where it will take the world’s first images of the magnetic field that protects Earth from solar radiation.

The Lunar Environmental Heliosphere X-ray Imager (LEXI) instrument is one of 10 payloads to be carried on board the next lunar transport under NASA’s Commercial Lunar Payload Services (CLPS) initiative, and is part of NASA’s F.L. It is scheduled to launch as soon as possible from the Kennedy Space Center. Firefly Aerospace’s Blue Ghost Lander in January. This instrument supports NASA’s goal of understanding how our home planet responds to space weather, or conditions in space caused by the Sun.

Once the dust from the moon landing clears, LEXI powers up, warms up, and refocuses on Earth. Over six days, it will collect images of X-rays emitted from the edge of Earth’s vast magnetosphere. This comprehensive view shows how this protective boundary reacts to space weather and other cosmic forces, and how it opens to allow streams of charged solar particles to enter and create aurora borealis. and how it can cause damage to infrastructure.

“We’re trying to get a complete picture of Earth’s space environment,” says Brian Walsh, an astrophysicist at Boston University and LEXI principal investigator. “A lot of physics is esoteric or difficult to understand without years of specialized training, but this makes it tangible science.”

LEXI will observe low-energy X-rays that are formed when a stream of particles from the Sun, called the solar wind, collides with Earth’s magnetic field. This occurs at the edge of the magnetosphere, called the magnetopause. Researchers were recently able to detect these X-rays in a patchwork of observations from other satellites and instruments. However, from a vantage point on the Moon, the entire magnetosphere is within LEXI’s field of view.

Back on Earth, the team will continue working around the clock to track how the magnetosphere expands, contracts and changes shape in response to the strength of the solar wind.

“We’re hopeful that for the first time we’ll be able to see the magnetosphere breathing in and out,” said Hyunjoo Conner, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and director of NASA’s LEXI. “I’m working on it,” he said. “When the solar wind is very strong, the magnetosphere contracts and is pushed back toward Earth, and when the solar wind weakens, it expands.”

The LEXI instrument is also poised to capture magnetic reconnections, where magnetic field lines in the magnetosphere merge with those in the solar wind, releasing high-energy particles that rain down on Earth’s poles. This could help researchers answer lingering questions about these events, such as whether they occur simultaneously at multiple sites and whether they occur on a steady basis or in bursts.

These solar particles streaming into Earth’s atmosphere can cause vivid auroras, but they can also damage satellites orbiting Earth and interfere with ground-based power grids.

“We want to understand how nature behaves, and by understanding this we can protect our infrastructure in space,” Connor said.

The CLPS delivery is not LEXI’s first space trip. The Goddard team, including Walsh, built the device (then called STORM) to test techniques for detecting low-energy X-rays over a wide field of view. In 2012, STORM was launched into space on a sounding rocket, collected X-ray images, and then fell back to Earth.

It ended up in Goddard’s display case, where it sat for 10 years. When NASA called for CLPS projects that could be executed quickly and on a limited budget, Walsh thought about the instrument and its potential for what could be seen from the moon’s surface.

“We’re not literally breaking glass, but by removing it, repairing it, and renovating it, we can look back and see a global picture that we’ve never seen before,” he said. said. Some old optics and other components have been replaced, but the instrument is in overall good condition and is now ready to fly again. “There’s a lot of really rich science that can come from this.”

Based on the CLPS model, NASA is investing in commercial delivery services to the Moon to enable industry growth and support long-term lunar exploration. As a major customer for CLPS deliveries, NASA aims to be one of many customers for future flights. NASA Goddard is LEXI’s principal scientific collaborator. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the development of seven of the 10 CLPS payloads aboard Firefly’s Blue Ghost lunar lander, including LEXI.