There’s heavy traffic in orbit. And those who “drive” the satellites, like Telespazio, are constantly on alert, waiting for a possible collision warning. It’s an alert indicating that two objects might crash into each other. In nearly seventy years — since the launch of the first artificial object, Sputnik — Earth’s orbits have been increasingly exploited without any real international regulation.In this second episode, Space Panorama takes you into the Telespazio Control Room at the Fucino Space Center, located in the Avezzano plain in Abruzzo, where space operations are overseen.“Telespazio’s job is to make sure satellites stay in their assigned orbits,” explains Andrea Cardellicchio, Head of Operations at Telespazio. “We also have to ensure they don’t go on a collision course with other objects in space, which can be either debris or other satellites operated by different providers.”
Firing the Thrusters to Avoid Danger
The first step in this process is receiving a collision alert, which typically comes from the U.S. Space Command.
“They send us a message identifying the risk of collision and the predicted time of impact,” Cardellicchio continues. “We then refine the analysis to determine the actual probability of a collision with this object.”
If needed, a collision avoidance maneuver is performed: the satellite is commanded to fire its thrusters and either raise or lower its orbit to move away from danger.
“The most dangerous objects are parts of rockets used to launch other satellites,” the Telespazio engineer adds. “Other risks come from defunct satellites that are no longer controlled, or satellites without propulsion systems on board. It’s as if they were pilotless — and they further increase orbital crowding and the collision risk for the satellites we operate.”
Sick Space: The Kessler Syndrome
All these objects remain orbiting Earth. They are often large and therefore pose a serious threat to active satellites. This is especially true in low Earth orbits (between 300 and 2,000 kilometers in altitude), now crowded with thousands of satellites.
There are about 10,000 active ones, but radars scanning the sky are also tracking hundreds of thousands of dead, uncontrollable satellites, fragments, and millions of pieces of debris created by past collisions, tank explosions, and scattered materials — space junk.
As the number of objects grows, so does the risk of collisions — and at orbital speeds, impacts are almost always damaging or even catastrophic. Collisions generate even more debris, further increasing the risk of new impacts. This creates a self-sustaining cascade known as the Kessler Syndrome, named after the American astrophysicist who first described the problem.
Mega-constellations like Starlink (with tens of thousands of satellites planned) and upcoming projects from Amazon and China are obviously part of the issue. In this scenario, coordination with other satellite operators has become essential to decide whether and how to maneuver.
One famous case involved a possible collision with a Russian satellite: “It happened right after the invasion of Ukraine,” recalls Cardellicchio. “Those were particularly tense days because, due to the breakdown in communications with Russia, we had to carry out the maneuver without any coordination with the other satellite’s operator — essentially flying blind.”