Leonard David's INSIDE OUTER SPACE

Image credit: NASA

A Georgia Tech study warns that increasing lunar traffic could lead to costly collision avoidance maneuvers. What’s now needed is better coordination to manage growing risks in cislunar space.

While collision probabilities in orbits around the Moon are very low compared to Earth orbit, spacecraft in lunar orbit will likely need to conduct multiple costly collision avoidance maneuvers each year.

The research has appeared in the Journal of Spacecraft and Rockets.

Moon maneuvers

“Our analysis suggests that satellite operators must perform up to four maneuvers annually for each satellite for a fleet of 50 satellites in low lunar orbit (LLO),” said one of the study’s authors, Brian Gunter, an associate professor in the Georgia Tech Daniel Guggenheim School of Aerospace Engineering.

NASA’s Lunar Reconnaissance Orbiter (LRO).
Credit: NASA’s Goddard Space Flight Center Conceptual Image Lab

According to the paper, a series of simulations were performed, using high-fidelity dynamics, in which the current 6 lunar satellites and approximately 50 future space objects were examined. Probabilities of collisions were computed and logged for those events that would likely result in a collision avoidance maneuver, along with other metadata regarding the location and parameters related to the conjunction.

“Our analysis suggests that satellite operators must perform up to four maneuvers annually for each satellite for a fleet of 50 satellites in low lunar orbit (LLO),” the researchers report. “With just 10 satellites in LLO, a satellite might still need a yearly maneuver. Most close encounters are expected to happen near the equator.”

Close approaches

The research work, led by Stef Crum, a 2024 graduate of Georgia Tech’s aerospace engineering doctoral program, said the work underscores the need for improved space domain awareness in the lunar environment.

“The close approaches were much more common than I would have intuitively anticipated,” Crum commented in a university press statement. Considering the small number of satellites in lunar orbit, “the need for multiple maneuvers was ‘really surprising.’”

Korea Moon orbiter.
Credit: KARI

The research points to a key finding: If operators aren’t coordinated about how they plan lunar missions, opportunities for collision will increase in “popular” orbits.

For more information, go to “Cislunar Orbit Collision Probability Analysis” in the bimonthly Journal of Spacecraft and Rockets published by the American Institute of Aeronautics and Astronautics (AIAA) at:

https://arc.aiaa.org/doi/epdf/10.2514/1.A36114