With the ever-increasing collision risk in orbit, a Space Traffic Management (STM) system is crucial to protect our satellites.
The increased accessibility to space in recent times and the miniaturisation of satellites has led to an intense growth of the number of space assets placed in already congested orbits. With more than 5,000 active and defunct satellites in low Earth orbit (LEO) alone and mega-constellations that will add thousands more in the coming years, issues related to space debris and space traffic management (STM) have become imperative for the safety of space operations. There are already more than 30,000 trackable debris pieces with a diameter of 10 cm or more, and about one million pieces larger than 1 cm, all of which threaten satellites and spacecraft. The latest uncontrolled re-entry brought to public attention was China’s Long March 5B core stage in May 2021 that was preceded by another uncontrolled re-entry of the same launcher series in May 2020 highlighted the need for STM and Space Situational Awareness (SSA) capabilities to effectively protect launch vehicles and orbiting objects in LEO and beyond. While commitments to best practices and a tentative set of rules have been established, clear incentives to operate in a way that guarantees the safe and sustainable use of orbital space are still lacking. Proactive STM capabilities will play a key role in the protection of critical space assets and the further development of the EU’s strategic autonomy in STM, ensuring safe and sustainable access to space for all.
| Source: ESA | |
| Red | Satellites (functional or dysfunctional) |
| Yellow | Rocket bodies |
| Green | Mission-related objects such as covers, caps, etc |
| Blue | Fragments |
To develop a sustainable and effective global STM system, standards and best practices will have to be determined through international cooperation, collaborative goalsetting. Although some elements of STM can be first tackled at the European level, the detailed development and ultimate application of best-practice requirements and norms for the responsible behavior of space actors shall be an international effort. Due to the size of the launch vehicle, safe disposal of launcher stages is of particular concern. A collision between a launcher stage during an uncontrolled re-entry and large space debris (> 10cm) or worse still a satellite would cause another steep rise in orbital fragments, not to mention the possibility of explosions further escalating the problem. More than 240 explosions and about 10 collisions have contributed to the total number of orbiting debris, estimated in circa 30.000 bigger than 10cm, 700.000 bigger than 1 cm, and 170.000.000 larger than 1 mm in diameter.
International best-practice requirements may call for some adaptations to the standards for operators, though in addition to guaranteeing a safer and more sustainable space environment will also lead to an increase in efficiency in the face of more common collision risks. Indeed, as the population of satellites in congested and competitive orbits increases, so will the need for collision alerts, both between spacecraft as well as between spacecraft and debris. Consequently, time-sensitive and accurate STM capabilities are expected to allow for greater precision in defining collision avoidance maneuvers, thereby reducing disruptions and fuel expenditures for orbital maneuvers.
The safety, security, and sustainability of outer space activities are rapidly leading to the need for the implementation of planned and coordinated STM activities, including end-of-life and de-orbiting operations. While the uncontrolled re-entry of the Long March 5B did not create any immediate consequence to satellites in LEO and fortunately crashed in the Indian Ocean, its 10 days of orbiting the Earth served as a grim reminder of the dangers of a “business-as-usual” approach to space sustainability. The furthering of both norms for responsible behavior (applicable to both public and private actors) as well as data and information sharing practices are avenues to be pursued within a broader European STM system.
The EU, with its tradition of openness and its well-developed intergovernmental and international collaboration networks has already laid the groundwork for the development of an advanced and reliable STM system. European strategic autonomy in STM has the potential to resemble similar to the development of the Galileo programme for navigation and its resultant relationship with GPS. This balance between autonomy and international cooperation for STM, already in place for navigation with Galileo-GPS, may enable safe access and use of space for both European and global operators.
 | This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101004319. This article reflects the author’s view and not necessarily the views of the European Commission or of the European Health and Digital Executive Agency |