Engineers Design Air Traffic Control System for Lunar Orbit

For decades, the moon belonged to one visitor at a time. A spacecraft would arrive, do its work, and leave—the whole celestial highway empty again. But NASA's vision for a sustained lunar base changes that calculus entirely. Soon, multiple ships will need to occupy the same orbital path simultaneously: crew capsules, cargo vessels, landers, all sharing space above the lunar surface. That requires rules. It requires traffic control.

Engineers from Texas A&M, Purdue University, and NASA's Johnson Space Center recently published a study outlining how to manage this orbital congestion. The work addresses a problem that sounds simple until you think about it: how do you keep spacecraft from colliding when they're all moving constantly through an orbit that has no ground, no runway, no physical infrastructure at all?

The orbit in question is called the near-rectilinear halo orbit, or NRHO. It loops around both poles of the moon, offering a sweet spot between fuel efficiency and access to the lunar surface. A single spacecraft can occupy it without much fuss. But add an Orion crew capsule, uncrewed cargo ships, and lunar landers all to the same path, and the mathematics becomes unforgiving. Diane Davis, an associate professor of space engineering at Texas A&M and one of the study's authors, put it plainly: collisions and serious damage become possible. Crew safety and mission success depend on effective traffic management.

The system works on principles familiar to anyone who has flown in an airplane. On Earth, air traffic control manages holding patterns, assigns runways, and clears airspace so planes don't meet mid-flight. The lunar version does something similar, but with complications that ground-based controllers never face. There is no physical airport. Spacecraft don't land on a tarmac—they wait in orbit, constantly moving, until conditions align for descent or departure. Engineers had to figure out how to "park" vehicles that never stop moving.

One fundamental problem is positioning. On Earth and in low orbit around it, GPS satellites tell you exactly where you are. In lunar orbit, that constellation doesn't exist. Controllers can estimate a spacecraft's location using radio signals from the Deep Space Network, which has stations in California, Spain, and Australia, or by using optical instruments aboard the spacecraft itself. But "estimate" is the operative word. Once a ship leaves Earth's GPS umbrella, no one knows its precise location—only an approximation.

The NRHO itself is hostile to spacecraft. Gravity from the moon, Earth, and distant celestial bodies all tug at anything in that orbit. Spacecraft must constantly adjust their trajectory to avoid crashing into one another, being pulled down to the lunar surface, or drifting into deep space. The new control system accounts for all these forces and has successfully simulated multiple spacecraft sharing the orbit without collision.

NASA announced its moon base plans in March, envisioning a three-phase program: first, sending supplies and equipment; second, building the base with nuclear power and other advanced technology; third, staffing it with rotating crews of humans. The entire effort is expected to take most of the next decade. The traffic control system is not glamorous—there's nothing to photograph, no hardware to display—but Davis emphasized its importance. The future of lunar exploration depends as much on managing traffic as it does on rocket science itself.

Interestingly, the NRHO was originally chosen for the Gateway space station, a project NASA later canceled in favor of moving directly to the moon base. That decision means NASA is now reconsidering which orbit to use, since it no longer needs to accommodate a permanent station. But the research applies regardless. Whatever orbit NASA ultimately selects, the principles of managing multiple spacecraft safely in cislunar space remain essential. The work represents a shift in how humanity thinks about the moon—not as a destination for isolated missions, but as a place where traffic flows, where rules matter, where the sky above the lunar surface needs its own air traffic control.