At 2 am on a Sunday in March 2025, a dozen scientists were gathered in a College of Engineering lab at Boston University in a tense, nail-biting silence. Almost 240,000 miles away, a shiny, golden spacecraft was slowly dropping toward the moon’s surface after traveling through space for 40 days. Mounted on best was a specially designed telescope, built at BU and known as LEXI, sent to capture views of Earth’s protective magnetic field that have never been seen before.
They waited in anticipation. Would the spacecraft land gently on the right spot? If it did, would it stay upright? Would it crash and destroy years of their work in the blink of an eye?
Nothing was certain. Moon landings are notoriously tricky feats. In 2024, a NASA-funded lander made by Intuitive Machines tipped on its side after landing faster than anticipated.
But by 2:30 am EST on March 2, 2025, the researchers got the news they’d been waiting—hoping—for.
“NASA, we are on the moon,” came a voice, as all eyes were on the mission’s computer systems used to communicate with the instrument and the spacecraft.
Project head Brian Walsh, an ENG associate professor of mechanical engineering, straightened up and smacked his hands together, his face awash in relief. Others cheered and let out their breath.
“We’re thrilled to reach this milestone,” said Walsh (GRS’09,’12). “There has been so much excitement leading up to this moment. The LEXI operations room exploded with high fives and hugs when we touched down. But a few moments later, it was some collective deep breaths to settle the heart rates and refocus back on the larger mission.”
The Blue Ghost Mission 1 spacecraft, built by the private company Firefly Aerospace and commissioned by NASA, had touched down successfully—a history-making landing for BU and for Firefly. The attached telescope, called the Lunar Environment heliospheric X-ray Imager (or LEXI) is the first device created by the University to land on another planetary body. It was also the first moon operation for Firefly, which became the first commercial company to successfully land on the moon.
Rousseau Nutter (ENG’20), a mechanical engineer at NASA Goddard Space Flight Center who returned to BU to help manage the project, was in the room when LEXI landed. “All right. Let’s get to work,” he said after the brief celebration. “We’re on the moon.”
Six hours later, LEXI powered up and opened its protective dust cover, exposing the imager’s lenses to the vast expanse of space.
From Lab to Lunar Landing
Getting LEXI from the lab to the moon took six years of researching, designing, engineering, and testing to make sure the 24-pound imager could withstand the intensity of spaceflight, handle drastic temperature swings, and communicate seamlessly to the ENG-based control room.
In March 2024, Walsh and his team transported the instrument by truck to Firefly Aerospace’s headquarters in Austin, Tex., where it was mounted on and integrated into the Blue Ghost lander. The LEXI team—among them Nutter, Emil Atz (ENG’23,’23), Cat Paw U (ENG’23,’24), Van Naldoza (ENG’20,’25,’26), Cadin Connor (CAS’20, ENG’22,’29), Anika Dujakovich (ENG’25,’27), research scientist Ramiz A. Qudsi, and Carl Schmidt (GRS’08,’13), a College of Arts & Sciences research assistant professor of astronomy—continued to connect and test LEXI through the lander’s computer systems.
And then, on January 15, 2025, Blue Ghost blasted off from the Kennedy Space Center in Florida, riding on a SpaceX Falcon 9 rocket. The spacecraft orbited Earth for 25 days, transited between Earth and the moon for 4 days, then went into lunar orbit for 16 days before landing on the moon.
LEXI’s goal was to get an unprecedented view of Earth’s magnetosphere, the magnetic bubble that shields us from charged particles and solar radiation. Specifically, Walsh says, the instrument was designed to image, for the first time, the boundary of Earth’s magnetic field, called the magnetopause, and the way it deflects the constant flow of solar wind and high-speed charged particles emanating from the sun.
The 24-pound LEXI imager had to be built to withstand the intensity of spaceflight, handle drastic temperature swings, and communicate seamlessly to the College of Engineering control room. The BU team put years of work—designing, building, testing—into the LEXI project. The telescope, pictured here, took images of the interaction of the solar wind and the Earth’s magnetic field. Photos by Michael D. Spencer
If you’ve ever seen the dazzling colors of the aurora borealis, then you’ve witnessed Earth’s magnetic field interacting with solar wind, creating a geomagnetic storm. The aim of LEXI was to view that phenomena from the opposite perspective: instead of looking up from Earth’s surface, it looked back at Earth from the vantage point of the moon. Once interpreted, LEXI’s data can help illuminate the magnetic relationship between Earth and the sun that has allowed life on Earth to exist.
Once the telescope touched down, the BU team didn’t have a moment to waste. They had only 10 days to record data before the setting sun plunged the moon into frigid darkness—with temperatures dipping as low as -208 degrees Fahrenheit and freezing Blue Ghost’s electrical components. All of the data had to be monitored in nearly real time to ensure it was recording as expected, according to Qudsi, a BU Center for Space Physics research scientist and lead data scientist and software developer for LEXI.
“I am most excited about seeing the fluctuations in the Earth’s magnetopause that we will be able to measure using LEXI data,” Qudsi says. “This hasn’t been done yet and LEXI provides a wonderful opportunity to do so.”
We’re thrilled to reach this milestone. There has been so much excitement leading up to this moment.
Unlike the telescope we use to spot stars and planets, LEXI records individual photons that result from a phenomenon called the solar wind charge-exchange, which is when charged atoms emitted from the sun slam into neutral particles, like hydrogen, in Earth’s outer atmosphere. The charged atom then steals an electron from the hydrogen. That exchange releases an X-ray in the process. Those invisible wavelengths of light, constantly present around our planet, can indicate how much solar wind is pushing up against Earth’s magnetic force field. When a lot of energy breaks through, geomagnetic storms form.
LEXI recorded those faint X-rays with special optical lenses—a design inspired by lobsters’ eyes, which can see in dark, murky environments—that pick up the faintest glowing signals. The BU team collaborated with researchers from NASA’s Goddard Space Flight Center, Johns Hopkins University, University of Miami, and the University of Leicester in the United Kingdom to develop LEXI’s lenses and machinery.
The week that LEXI was collecting data was a tiresome stretch. Each team member rotated in and out of the control room in eight-hour shifts so the information could be monitored 24 hours a day.
“It was a very intense week,” says Walsh, who first began measuring X-ray signals in the atmosphere as a postdoctoral researcher at Goddard. There were some challenges while LEXI was on the moon, including higher- and lower-than-anticipated temperatures. But the Blue Ghost and LEXI stayed the course. Nutter, who handled the team’s schedule, says everyone executed the plan flawlessly. “We have a fabulous team that made it extremely easy to manage the schedule,” he says.
In total, LEXI operated for more than 150 hours on the lunar surface, accumulating a trove of valuable data. Toward the end of the mission, on March 14, Blue Ghost witnessed a total solar eclipse, when the Earth blocked the sun; a couple of days later, LEXI recorded the sun set on the moon. “We saw some really interesting things about how the surface of the moon changes as the sun sets, and got some really good data,” Walsh says.
We saw some really interesting things about how the surface of the moon changes as the sun sets.
By 5:19 pm EST on March 16, about five hours after sunset, LEXI shut down for the final time. And by 7:10 pm, several hours into the lunar night, Blue Ghost’s batteries reached zero, as expected, making it impossible for the instruments to turn back on. The lander will stand powerless, with LEXI pointing up to the sky, for the foreseeable future, shining in the windless landscape of the moon.
The Next Phase
today, the LEXI team is tasked with analyzing hours of images recorded from the lunar surface and painting a picture of Earth’s magnetic field boundary.
The data can help answer some big questions, such as predicting when and how Earth receives high amounts of energy from the sun that cause geomagnetic storms. “We live in this bubble, this magnetosphere,” Walsh explains. “Some days, a lot of energy breaks into that magnetic bubble. We’re trying to understand how that process works.”
It’s unclear if those high-energy days are a result of changes in the solar wind, or if energy is building up and then penetrating the magnetosphere in one big burst, or if energy is getting absorbed gradually into the magnetosphere like a constant stream of wind. This is important to know. During big geomagnetic storms, satellites need to be raised in their orbits, because the lower atmosphere becomes dense from increased heat and energy that drag satellites down. Storms can also result in disturbances to radio communications, navigation technology, and aerospace systems.
Walsh hopes LEXI’s data can help inform models that predict those days of extreme space weather.
“I’m proud of everything the team has done, through development, launch, flight, and surface operations,” he says. “We’ve just begun to work through the science data but have already started to discover new things about the lunar surface and our local space environment. Looking back, the team is proud to have left a set of paw prints in the lunar regolith as the first Terrier on the moon.”
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