Space is often described as “vastly, hugely, mind-bogglingly big,” but Low Earth Orbit (LEO)—where a multitude of satellites currently resides—is far more limited than it appears. With thousands of satellites already in LEO and tens of thousands more anticipated, a significant concern has arisen: the potential for overcrowding that could render this orbital space ineffective for satellite operations due to interference and collision risks.
A new study by MITRE aims to establish a framework to determine when the volume of space traffic in LEO becomes unmanageable. The work, titled “Integrating Orbital Carrying Capacity into International Policy Constructs: Leveraging Best Practices from Aviation’s Risk-Based Norms,” proposes adapting elements from international air traffic control to manage orbital traffic and prevent collisions, as stated by MITRE’s Vice President Kevin Toner.
During the annual Advanced Maui Optical and Space Surveillance Technologies (AMOS) conference, Toner and his colleagues discussed the study, which will be presented at the 75th International Astronautical Conference in October. The rapid increase in satellites in LEO, situated approximately 300-2,000 kilometers above Earth, has raised global concerns regarding the “carrying capacity” of this orbital regime. Like terrestrial spaces, LEO has a finite capacity, and overcrowding could significantly elevate the likelihood of catastrophic collisions and the creation of space debris.
At a recent meeting of the UN Committee on the Peaceful Uses of Outer Space, the issue of LEO congestion and equitable access for developing nations was highlighted. Mega-constellations, comprising thousands of satellites launched by commercial enterprises and governments, have been identified as significant contributors to potential overcrowding.
For instance, SpaceX has deployed around 6,000 Starlink satellites in LEO, with plans to expand to over 40,000. The company has also launched militarized versions of Starlink, known as Starshield, for the National Reconnaissance Office. Similarly, Amazon’s Kuiper Project introduced the first two satellites of a planned 3,000-satellite constellation in 2023, while OneWeb has successfully placed 630 of its 648 planned satellites into orbit.
China’s ambitions in this domain are also notable, as its state-owned Shanghei Spacecom Satellite Technology recently launched the first 18 satellites of the Thousand Sails (G60) project, which plans to encompass roughly 15,000 satellites. Moreover, the Space Force’s Space Development Agency aims to deploy up to 500 satellites for a data relay network and an additional 100 for missile tracking.
MITRE’s study proposes a strategic approach to managing orbital traffic by segmenting space into specific altitude bands and incorporating temporal aspects into the analysis. “There are many definitions of carrying capacity, but we emphasize considering factors like timing and orbit congestion,” Toner noted.
By applying principles from air traffic management—classifying orbital regions similar to airspace classifications—the study aims to inform better regulatory practices. For instance, the 700-900 kilometer orbital range is likened to heavily congested Class A air corridors, with Earth’s poles (where many satellites converge) identified as Class B, and higher orbits above 1,000 kilometers as Class C.
The ultimate objective of the MITRE proposal is to facilitate international collaboration and establish standardized regulations that ensure the safety and sustainability of space activities. By developing globally harmonized policies, the study strives to create a path toward effectively managing the increasing satellite traffic in LEO while preserving access for all users.
