why Satellites do not collide with each other

There are thousands of satellites orbiting Earth. But 99% Satellites do not collide with each other in space due to careful planning, coordination, and the vastness of space. Several factors contribute to the avoidance of collisions:

1. Orbital Altitudes and Inclinations: Satellites are placed in different orbital altitudes and inclinations, which means they follow distinct paths around Earth. These differences in orbits help minimize the chance of collisions. There are specific regulations and guidelines for satellite operators to ensure safe separation between satellites.

2. Space Traffic Management: Organizations responsible for space activities, such as national space agencies and international organizations, actively manage and track satellites in orbit. They monitor the positions and trajectories of satellites to predict potential collisions and provide warnings to operators to adjust orbits if needed.

3. Launch Planning: When satellites are launched, the timing and trajectory are carefully calculated to ensure they reach their intended orbits without coming into close proximity with other satellites. Launch providers work with space agencies to ensure that satellites are placed in safe and designated orbits.

4. Collision Avoidance Maneuvers: In some cases, if the tracking data indicates a potential collision risk, satellite operators can execute collision avoidance maneuvers to change the satellite's orbit and avoid a collision.

5. Space Debris Mitigation: Mitigation measures, such as designing satellites to re-enter Earth's atmosphere at the end of their operational life, contribute to reducing the overall population of objects in orbit. This helps prevent the accumulation of space debris that could increase the risk of collisions.

6. Technology and Tracking: Advanced radar and tracking systems are used to monitor the positions of satellites and track potential collisions. This information is used to predict and prevent close approaches.

7. Coordination and Communication: Satellite operators and space agencies communicate and coordinate to share information about their satellites' positions and planned maneuvers. This cooperation helps ensure safe distances between satellites.

While collisions between satellites are rare due to these precautions, the growing number of satellites and space debris in orbit has led to increased attention on space traffic management and collision avoidance efforts. As the number of satellites continues to increase, maintaining safe and sustainable operations in space becomes even more important.

Past collision incidents

Here are a few examples.

1. Iridium 33 and Cosmos 2251 (2009): In February 2009, an operational Iridium communication satellite, Iridium 33, collided with the defunct Russian satellite Cosmos 2251. The collision occurred in low Earth orbit and resulted in the creation of thousands of pieces of debris.

2. Fengyun-1C and USA-193 (2007): In 2007, the Chinese satellite Fengyun-1C was deliberately destroyed by a Chinese anti-satellite missile test. This test created a large amount of debris. In a separate incident the same year, the U.S. military shot down its defunct satellite, USA-193, to prevent the uncontrolled re-entry of hazardous materials.

3. Close Encounters: There have been numerous instances of close encounters between operational satellites and defunct satellites or space debris. These close approaches highlight the importance of space traffic management and collision avoidance measures.

4. Near-Miss with Sentinel-1A and a Debris Fragment (2016): In 2016, the European Space Agency's Sentinel-1A radar satellite narrowly avoided a collision with a small debris fragment from a Chinese satellite explosion. The fragment passed within a few hundred meters of Sentinel-1A.