After 40 days of traveling through space, a shiny, golden spacecraft gently lands on the surface of the moon. The autonomous moon lander, with 10 aerospace instruments onboard, faces Earth—238,855 miles away. As the dust beneath it settles, a clear view of our home planet emerges. The scientists who have spent years preparing for this moment, eagerly awaiting its arrival and ready to view Earth in a whole new way, can finally breathe. 

At least, that’s how Boston University engineer Brian Walsh hopes the landing of NASA’s Blue Ghost Mission 1 all unfolds. 

That’s because one of the instruments hitching a ride on the Blue Ghost lander is a telescope created by Walsh, a BU College of Engineering associate professor of mechanical engineering, and his team. The Lunar Environment heliospheric X-ray Imager (LEXI) will be the first BU-created device to ever land on another planetary body. Although LEXI hasn’t left the atmosphere yet, the lander is scheduled to launch on a SpaceX Falcon 9 rocket from the Kennedy Space Center in Florida between January 15 and 17. For now, Walsh and his collaborators are bracing themselves for Blue Ghost—designed by private company Firefly Aerospace and commissioned by NASA—to blast off. 

Blue Ghost is one of eight US landers anticipated to take off in the next two years and will deploy on the near side of the moon, in a flat region called Mare Crisium. Once LEXI opens its protective dust cover—mounted on top of the lander—it will get an unprecedented view of Earth’s magnetosphere, the magnetic bubble that shields us from harmful charged particle radiation.

“LEXI will image, for the first time, the boundary of Earth’s magnetic field,” Walsh says, and how it deflects the constant flow of solar wind and high-speed charged particles emanating from the sun. If you’ve ever seen the dazzling colors of the aurora borealis, then you’ve witnessed the result of Earth’s magnetosphere interacting with solar wind, creating a geomagnetic storm. The goal of LEXI is to view that phenomena from the opposite perspective—instead of looking up from Earth’s surface, it will look back at Earth from the vantage point of the moon.

But for that to happen, everything must go according to plan. Unfortunately, that is never a guarantee with space travel. 

Last January, the first NASA-commissioned lander mission malfunctioned, and never made it past the atmosphere. The next one launched and successfully landed in February 2024. Blue Ghost will mark the agency’s third attempt to ship payloads to the moon using a private company’s vehicle, its mission ignited by NASA’s efforts to conduct research in different lunar regions. The agency’s ultimate goal is to create the first moon-based space station to serve as a launch point for going to Mars. 

Preparing for a moon mission is both thrilling and nerve-racking, according to Walsh, but the inherent uncertainty is pushed aside by intense preparation and rigorous testing of the device. His team at BU received funding from NASA in 2019 to design and build the telescope. For Walsh though, LEXI is a culmination of 15 years of work that started while he was a postdoctoral researcher at NASA’s Goddard Space Flight Center, where he began measuring X-ray signals in the atmosphere. 

“Hundreds of years ago, people had great knowledge of the magnetic field of Earth for navigation on the surface of Earth, and now we know that same magnetic field extends out into space where it protects us from solar wind,” Walsh says. “We still don’t know what the outer edge of that field looks like, the shape of it or how it gets compressed, so seeing this grand picture is really important for understanding the space environment around the Earth.” 

In the months and years since the LEXI project kicked off, the team has been hard at work: choosing materials (an early prototype made of plastic was jokingly nicknamed “Plexi”), doing the math to determine the ideal dimensions, adding electronics and computing systems, crafting specially engineered glass lenses, testing its durability. The 24-pound telescope needs to withstand intense vibrations, temperature swings, and communicate seamlessly to the lab’s control room.

The device’s innovative optical lenses mimic lobster eyes—technology prototyped in the 1990s that was inspired by how well lobsters can see in dark, murky environments—that pick up even the faintest glowing X-ray signals, called soft X-rays. The crustacean-inspired lenses in LEXI were specially fitted to withstand spaceflight. Walsh and his team, who collaborated with researchers from NASA Goddard, Johns Hopkins University, University of Miami, and the University of Leicester, published a technical overview of the telescope in Space Science Reviews. 

When it wasn’t undergoing examination, LEXI was stored in a sealed vacuum chamber on BU’s Charles River Campus, so not even a particle of dust could interfere with its operation. In March 2024, the device made its final appearance in a clean room at the College of Engineering, where community members could glimpse the device before it left. The next day, Walsh and the team carefully—so carefully—began transporting the device by truck to Firefly Aerospace’s headquarters in Austin, Tex., where it was mounted and integrated to the Blue Ghost lander. That was the last time Walsh saw the telescope in person.

“I imagine the feeling is similar to sending a child off to college. You spend so much time working with someone and taking care of them and monitoring everything they do, and then you hand them off and you have to say alright, let’s do it,” Walsh says. 

Now, he connects to the telescope through the lander’s computer systems. And the work hasn’t stopped. The team has been in consistent contact with Firefly to continue testing LEXI and simulating the mission before takeoff. 

“The simulations have been long and intense,” Walsh says. There have been some that last for 24 hours a day for a week straight—exactly how it will be when the lander touches down on the moon, giving the team the opportunity to practice taking shifts monitoring the data received in real time. Walsh says that everything has been smooth. They anticipate that in the minutes after LEXI powers up and begins recording data, they will receive X-ray signals that will paint the picture of the Earth’s magnetic field boundary.

These X-rays are released when a charged atom emitted from the sun, like an oxygen ion, slams into a neutral particle, like hydrogen, which floats around in abundance at Earth’s outer atmosphere. When the particles collide, the oxygen ion steals an electron from the hydrogen, and that process releases an X-ray. LEXI will record those invisible wavelengths of light, constantly present around our planet, for seven days. After that, the sun will set on the moon and it’s expected that icy temperatures—dipping as low as -208 degrees Fahrenheit—will disable the lander and all of its payloads permanently. 

It’s a short window, but “there are big outstanding questions that this data will help answer,” Walsh says, like being able to predict when and how Earth receives more energy from the sun that causes geomagnetic storms. “We live in this bubble, this magnetosphere. 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 into 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. When there are big geomagnetic storms—like when the aurora borealis was visible in Massachusetts in October 2024—thousands of satellites need to suddenly be raised in their orbits, because the lower atmosphere becomes much more dense, dragging them down. Storms can also result in disturbances to radio communications, navigation technology, and aerospace systems. LEXI’s data will help inform models that can predict those days of extreme space weather and help experts prepare for them. 

With so much to discover, the launch of Blue Ghost will be the beginning of the science Walsh and his team have prepared for. The mission will orbit Earth for the first 25 days, spend 4 days in transit, then orbit the moon for 16 days before touchdown. From their BU-based control room, they’ll trigger a latch on the front of the telescope that will open a small door, exposing LEXI’s lenses to the expanse of space. All of the hours and years will pay off when they receive data illuminating the magnetosphere boundary, providing insights into the electromagnetic relationship between Earth and the sun that has allowed life on Earth to exist.

“Getting the very first picture of Earth’s magnetic field will be extremely exciting,” Walsh says. 

In the coming weeks, The Brink will be charting LEXI’s progress, from the upcoming launch to the landing of the Blue Ghost to Walsh’s analysis of the data. Follow BU on social media and check back on The Brink for more stellar updates.