Towards space traffic management

Today’s active satellite infrastructure provides a multitude of critical services to citizens, and includes communication, weather, navigation, and Earth monitoring missions. Its loss would severely damage modern society. Even more, a new era in space has just started, driven by commercial low latency broadband services, using large constellations of satellites in low-Earth orbit (LEO). These systems will revolutionise connectivity on ground, on the road, and in air. However, they also come with an increase in space traffic. The number of satellites to be launched in the next five years will surpass the number of satellites ever launched globally over the whole history of spaceflight up until today.

Managing the risks for and of space traffic takes place on the basis of non-binding guidelines that are progressively translated into national regulation. However, 20 years after such measures have been proposed and applied across the industry, several dozens of large space objects still get stranded every year in critical orbital regions, where they will remain for several hundred years. Furthermore, an average of eight on-orbit fragmentation events occurs every year, contaminating the environment with additional fragments.

As a result, operations in space are facing more burdens, not only related to the risk of losing a mission, but also from an increase in evasive manoeuvres. Today, missions in densely used altitude layers receive several dozens of collision warnings per day, of which only the most critical can be avoided. The efforts associated with limiting such collisions are set to increase in line with the onset of large constellation traffic. This will not only raise the number of conjunction alerts, but also increase coordination efforts, since active-on-active conjunctions will occur more frequently. There are no flight rules available to manage such a scenario, nor is communication between space operators subject to specific rules or norms. This chapter explains how standardisation and voluntary coordination action can prepare the ground for a regulatory approach to space traffic management (STM).