Hundreds of satellites could soon be flying in orbital regions already too crowded to allow safe, long-term operations, a new study suggests.
The study found that while in 2019 only 0.2% of satellites in Earth in orbit were forced to perform more than 10 collision avoidance maneuvers per month, this percentage had increased sevenfold by the start of 2025, to reach 1.4%. This figure may still seem low, but it means that around 340 satellites spend a lot of time avoiding debris and other spaceships.
Furthermore, the satellite population is expected to continue to grow. While in 2019 around 13,700 objects (including space debris) zoomed around the planet low earth orbit (LEO), at altitudes below 1,200 miles (2,000 kilometers), that number has since increased to 24,185 objects in 2025, an increase of 76%, according to the study. By the end of this decade, some 70,000 satellites could reside in LEO, according to industry growth forecastwhich represents a more than fivefold increase compared to the situation in 2019.
Study team members reported selecting 10 collision avoidance maneuvers per month as a threshold at which satellite operation may become too complicated to be beneficial.
“Operators don’t want to spend all their time worrying about avoiding collisions,” study co-author Maya Harris, a research assistant and graduate student in science at the Massachusetts Institute of Technology (MIT), told Space.com. “They don’t want to spend all their propellant doing maneuvers.”
The researchers used data from the space object catalog maintained by US Space Command and modeled the probability of a collision for each pair of objects, satellites and debris, residing in the same orbital region. Whenever two objects came within 200 meters of each other, the researchers noted that the event required a collision avoidance maneuver.
Different operators choose a different threshold to perform collision avoidance maneuvers. NASA spacecraft primarily maneuver when the risk of collision is greater than 1 in 100,000. EspaceX — the world’s largest satellite operator, with its broadband megaconstellation Starlink — is being more cautious, using its autonomous space dodge system to avoid an object posing a greater risk. more than 1 in a million.
The frequent maneuvers present a disruption to operations that some satellite managers are better able to absorb than others, Hugh Lewis, a space debris expert and professor of astronautics at the University of Birmingham in England, told Space.com.
“For an Earth observation spacecraft, there’s probably a much larger disturbance to perform a maneuver, because they have to control their altitude and tilt very precisely in order to achieve a particular ground trajectory,” said Lewis, who was not part of the new study. “But for spacecraft like Star linkthey have great flexibility in what orbits they can be in and still provide service. »
In addition to the disruption of service, the success of evasive maneuvers is not guaranteed. Spatial tracking is not perfectly precise and calculation errors are possible. Additionally, previous studies have shown that performing an avoidance maneuver creates a higher risk of subsequent collision with another spacecraft, because this changes the satellite’s trajectory in ways that collision prediction algorithms cannot immediately account for. The more satellites there are in orbit, the higher the risk of failure of one of these maneuvers.
Lewis said the data suggests there is already about a 10 percent chance of an orbital collision occurring within a year. A total satellite collision would create thousands of new debris fragments, further increasing the need to maneuver operational spacecraft into close orbits and thus increasing the likelihood of subsequent collisions. It is this risk of collision which concerns both researchers and operators.
“If we have more collisions generating a lot of debris, that will allow us to reach our (full orbital) capacity much sooner,” Harris said.
Lewis said that according to the last report filed with the U.S. Federal Communications Commission, SpaceX’s Starlink satellites performed 145,000 collision avoidance maneuvers in the six months to July 2025. That would equate to about four maneuvers per satellite per month.
“They seem to be adapting to this very well,” Lewis said. “They don’t seem to be saying it’s really getting difficult, so maybe they could accommodate even if we get to 10 a month.”
The new study finds that satellites orbiting at certain altitudes face more congestion than others. In orbital regions between 400 and 600 km altitude and between 700 and 800 km altitude, many satellites are already forced to avoid collisions more than 10 times per month.
“Although most of the orbit is not yet at full capacity, some regions already are,” Harris said. “The two most affected areas are between 400 and 600 kilometers, where there are many active satellites, and then between 700 and 800 kilometers, where there is a lot of space debris.”
The new study suggests that satellite operators may be able to make better use of available space by launching less into already crowded orbits and operating their constellations in a coordinated manner so that their satellites’ orbits are synchronized rather than intersecting.
Lewis, however, questions whether global coordination of satellite operations is feasible. SpaceX is currently by far the largest satellite operator, but the company may soon have competition for that title: Countries around the world, including perceived adversaries like China, are considering developing their own satellite constellations. tens of thousands of satellites.
“I don’t think it’s likely that SpaceX and the Chinese will coordinate how they structure and operate their systems,” Lewis said.
The study was published in the October issue of the journal Acta Astronautica.