How can we prevent satellite collisions in an overcrowded space?

Recent reports indicate a near-collision between an Australian satellite and a suspected Chinese military satellite. Additionally, the US government levied its first-ever space junk fine, imposing a $150,000 penalty on DISH Network, a satellite TV services provider, for its 21-year-old communications satellite, EchoStar-7. The fine was due to its failure to adhere to previously agreed-upon debris mitigation plan orbit requirements.
This incident marks the beginning of a new era in space usage, with the number of active satellites projected to increase by 700% by the decade’s end. As space around our planet becomes increasingly congested, ensuring the safe navigation of thousands of satellites and space debris fragments gains paramount importance. This necessity has given rise to the field of space domain awareness, which focuses on monitoring and managing satellites and space debris in Earth’s three primary orbital regions, signifying the growing significance of space traffic management in our modern world. Currently, there are over 8,700 active satellites in various Earth orbits.
Understanding the intricacies of space debris involves recognizing the three primary satellite orbits. Low Earth orbit, the most common, hosts at least 5,900 active satellites positioned up to 1,000km above Earth’s surface, constantly in motion. Notably, the International Space Station orbits in this region, completing 16 circuits around Earth each day. Moving higher, we encounter medium Earth orbit, situated between 10,000 and 20,000km above Earth. Although less crowded, it accommodates critical satellites like those powering the Global Positioning System (GPS). These varying orbits play a pivotal role in satellite functionality and the challenges of managing space debris.
How do we track them all? This is where space domain awareness comes in. It is the field of detecting, tracking and monitoring objects in Earth’s orbit, including active satellites and space debris.
We do much of this with ground-based tracking, either through radar or optical systems like telescopes. While radar can easily track objects in low Earth orbit, higher up we need optical sensors.