The study found that, while in 2019 only 0.2% of satellites in Earth orbit were forced to perform more than 10 collision-avoidance maneuvers per month, that percentage had risen sevenfold by early 2025, to 1.4%.
That number might still seem low, but it means that some 340 satellites spend a lot of time dodging debris and other spacecraft.
The study team members said that they selected 10 collision-avoidance maneuvers per month as a threshold at which satellite operation may become too complicated to be beneficial.
Different operators choose a different threshold to perform collision-avoidance maneuvers.
The new study found that satellites orbiting at certain altitudes face more congestion than others.
According to a recent study, hundreds of satellites might soon be operating in orbital regions that are already too crowded to support long-term, safe operations.
The study discovered that by early 2025, 14% of satellites in Earth’s orbit were required to perform more than 10 collision-avoidance maneuvers per month, a sevenfold increase from just 0.2 percent in 2019. Even though it may not seem like much, that figure indicates that 340 satellites are constantly avoiding spacecraft and debris.
Furthermore, the number of satellites is expected to continue increasing. In 2025, there will be 24,185 objects in low Earth orbit (LEO), which is a 76% increase from the 13,700 objects (including space junk) that zoomed around the planet in 2019 at altitudes below 1,200 miles (2,000 kilometers). Industry growth forecasts indicate that by the end of this decade, nearly 70,000 satellites may be in low Earth orbit (LEO), more than five times as many as in 2019.
The members of the study team stated that they chose a monthly threshold of 10 collision-avoidance maneuvers as the point at which satellite operation might become too complex to be valuable.
Research assistant and Massachusetts Institute of Technology (MIT) science graduate Maya Harris told Space . com, “Operators don’t want to be spending all their time worrying about collision avoidance.”. The last thing they want is to use up all of their propellant on maneuvers. “.
Data from U’s catalog of space objects was used by the researchers. S. Space Command and calculated the probability of a collision for every pair of objects—debris and satellites alike—that were in the same orbital zone. The researchers observed that a collision-avoidance maneuver was necessary each time two objects were within 200 meters (less than 66 feet) of one another.
In order to execute collision-avoidance maneuvers, different operators select a distinct threshold. Most NASA spacecraft maneuver when there is a greater than one in 10,000 chance of a collision. Being more cautious, SpaceX, the largest satellite operator in the world with its Starlink broadband megaconstellation, uses its autonomous space dodging system to steer clear of an object that poses a risk greater than 1 in 3 million.
According to Hugh Lewis, a space debris specialist and professor of astronautics at the University of Birmingham in England, frequent maneuvers cause a disruption to operations that some satellite handlers can better handle than others, Space . com reported.
Lewis, who did not participate in the new study, stated, “There’s probably a much bigger disruption to make a maneuver for an Earth-observation spacecraft, because they have to control their altitude and inclination very precisely in order to achieve a particular ground track.”. However, Starlink and other spacecraft have a lot of leeway in terms of the orbits they can be in while still providing the service. “.”.
Aside from the service interruption, the success of the avoidance techniques is not assured. Mistakes can happen because space tracking is not always accurate. Furthermore, prior research has demonstrated that executing an avoidance maneuver increases the likelihood of a subsequent collision with another spacecraft because it modifies the satellite’s trajectory in a way that collision-prediction algorithms might not recognize right away. The likelihood that one of these maneuvers will fail increases with the number of satellites in orbit.
According to Lewis, data indicates that the likelihood of an in-orbit collision occurring within a year is already about 10%. There would be thousands of new debris fragments from a full-on satellite collision, increasing the need for operational spacecraft in nearby orbits to maneuver and increasing the likelihood of more collisions. Both researchers and operators are concerned about this collision risk.
According to Harris, “we will reach [full orbital] capacity much sooner if we have more collisions that create a lot of debris.”.
According to Lewis, the most recent report submitted to the U.S. S. . SpaceX’s Starlink satellites executed 145,000 collision-avoidance maneuvers in the six months before July 2025, according to the Federal Communications Commission. That would equate to about four satellite maneuvers every month.
“They seem to be able to accommodate that really well,” Lewis remarked. “Even if we reach the ten per month, they might be able to accommodate it because they don’t seem to be saying that things are getting really difficult. “.”.
According to the new study, there is more congestion for satellites orbiting at particular altitudes than for others. Several satellites already have to avoid collisions more than ten times a month in orbital regions between 25 and 370 miles (400 and 600 km) and 435 and 500 miles (700 and 800 km).
“Some regions of the orbit are already at capacity, even though the majority of it is not yet,” Harris said. Between 400 and 600 kilometers, where there are a lot of active satellites, and between 700 and 800 kilometers, where there is a lot of space debris, are the two most impacted regions. “.”.
By launching fewer satellites into already overcrowded orbits and coordinating the operation of their constellations so that their satellites’ orbits are in sync rather than crossing one another, satellite operators may be able to make better use of the available space, according to the new study.
Lewis, however, questions the viability of satellite operations being coordinated globally. Currently, SpaceX is the largest satellite operator by far, but it may soon face competition as nations all over the world, including China and other perceived enemies, are planning to build their own constellation of tens of thousands of satellites.
“The possibility that SpaceX and the Chinese would coordinate how they structure and operate their systems is unlikely,” Lewis stated.
The Journal Acta Astronautica published the study in its October issue.
