SpaceX recently announced that its Starlink broadband satellite constellation, in addition to providing high-speed and low-latency Internet services, is being given a new role as a space situational awareness system called "Stargaze" to track and manage low-Earth orbit traffic and act as an orbital "traffic police." There are currently about 9,600 Starlink satellites in orbit, and the long-term planning scale is as high as 42,000. This huge constellation is not only used to transmit data and video, but is also regarded by SpaceX as a potential space monitoring infrastructure.
Each Starlink satellite is equipped with a star-sensitive camera (star-tracker), which is the standard equipment for attitude control of spacecraft. It can judge its own attitude by photographing the starry sky and comparing it with the star map. The principle is similar to the sextant navigation in traditional navigation. The star sensitivity of a single satellite is not special, but when nearly 10,000 satellites are in orbit at the same time and continuously scan the sky, a wide-covering optical observation network is formed, providing new possibilities for real-time tracking of orbital targets.
The article pointed out that although space is extremely vast in scale, it stands to reason that the spacecraft launched by humans in the past 70 years will almost "not see each other" even if they are distributed in the cislunar space. However, in reality, the situation is more like sea lanes: spacecraft often concentrate on operating at specific altitudes and orbital corridors, similar to ships gathering in shipping lanes and straits, which significantly increases the risk of collision in local areas. In these "orbital channels", how to grasp the positions and trajectories of various spacecraft and debris in real time has become a priority task for space agencies and operators in various countries.
Traditional space monitoring relies on two pillars: first, each satellite operator proactively discloses its satellite orbit parameters and promptly reports when the orbit or attitude changes; second, ground-based radar and telescope networks continuously monitor the sky. However, in actual operations, operators do not always report orbit changes completely or in a timely manner. Ground observation stations are limited by line of sight, weather, and observation time windows. It is often difficult to track each target at high frequency and for a long time. Accurate orbit calculation often takes several hours, and it is difficult to cover "space junk" such as leftover rocket debris in a timely manner.
SpaceX says this is not just a theoretical risk, but a real risk that has already emerged. In 2025, a third-party satellite was originally planned to pass about 9,000 meters near a Starlink satellite, but the trajectory was adjusted without sufficient notification, and the distance at the closest point was shortened to about 60 meters, greatly increasing the potential collision probability. If a collision occurs, a large amount of debris may be generated, posing a threat to other satellites in surrounding orbits for several months. It is said that relying on the trajectory update capability of the Stargaze system, the control team was able to correct the Starlink satellite orbit in time to avoid this close and dangerous contact.
SpaceX said that there are approximately 30,000 tracking cameras in its constellation, which can continuously detect and track orbital targets, and cumulatively build a huge observation database, thereby significantly compressing orbit calculation time from hours in the past to minutes. On this basis, with the help of the space traffic management platform, close encounters between spacecrafts can be predicted earlier, and time can be reserved to take maneuvering avoidance and other measures to improve the safety of the entire low-Earth orbit environment.
The Stargaze system has now completed its beta operation, and the orbital ephemeris (ephemeris) generated by it are open to the public and are updated hourly. However, SpaceX also emphasized that Stargaze cannot replace the transparency obligations of each operator in data disclosure. Satellite operators should still proactively and timely share any orbit change information to reduce misjudgment and risk accumulation.