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To solve space traffic woes, look to the high seas

Ruth Stilwell, an expert in space and aviation policy, thinks the best way to protect spacecraft is to adopt lessons from maritime law.
August 23, 2021
esa satellite
esa satellite

Thanks mainly to the rise of satellite megaconstellation projects like OneWeb and SpaceX’s Starlink, the American Astronomical Society suggests, it’s possible we may see more than 100,000 satellites orbiting Earth by 2030—a number that would simply overwhelm our ability to track them all. Experts have repeatedly called for a better framework for managing space traffic and preventing a future plague of satellite crashes, but the world’s biggest space powers are still dragging their feet. All the while, more and more objects are zooming perilously close to one another. 

Ruth Stilwell, the executive director of Aerospace Policy Solutions and an adjunct faculty member at Norwich University in Northfield, Vermont, has a suggestion for how we can better manage space traffic. She argues that we should look to the maritime laws and policies developed over hundreds of years to guide how ships and other vessels on the sea ought to behave.

Can you start off by giving me the lay of the land of space traffic management and space situational awareness today? How would you evaluate how well the world currently does these things? 

Space traffic management is very much an emerging field. We’re in the early stages, where the discussions in the international community are in the development of norms and standards of behavior. The fundamental purpose of space traffic management is to prevent collisions in space. Collisions, by their nature, are debris-generating events, which cause the domain itself to become polluted and less safe for future actors. So it’s twofold—it’s not just that a collision damages satellites; a collision also causes long-term damage to the environment itself. And we see that very clearly in all of the evaluations of the [2009] Iridium-Cosmos collision.

Space situational awareness is a different thing—it’s about providing data. Different countries and companies around the world detect where these objects are in orbit and share what’s out there. For 50 years, you didn’t really need much information other than [the location of debris so it can be avoided]. But as the orbital domain becomes more congested with junk, it’s not just a question of “How do you avoid debris?” It’s now “How do you interact with other [satellite] operators up there?” When there’s two maneuverable satellites that want to be in the same place at the same time, that’s when you get to that question of management rather than space situational awareness. 

Along those lines, when there is a possible collision between two objects, what’s the general process in place to prevent a disaster from ensuing? Is there a quick outline you can provide?

I’ve been on a quest to find an authoritative reference that talks about the process from end to end. I wish I could say, “Go to this resource, and it’ll show you what happens from the time they look for a close approach to the time that the decision is made for whether or not to maneuver a satellite.” But it’s a bit opaque. Different operators have different internal processes that they don’t necessarily want to share. 

The US Space Force’s 18th Space Control Command Squadron is constantly watching the skies and reevaluating the situation every eight hours. If they detect that a close approach is possible, they’ll issue a conjunction alert to the owner-operator of the satellite. Then it goes into the hands of the owner-operator to decide what to do with that information. And then the 18th will continue to monitor things. The projection of where something might be in space varies wildly based on the object, how it’s shaped, how it reacts to the atmosphere around it … If there’s any intention by the operator to move it on purpose, that changes the observations as well.

You’ve argued that while air traffic control might seem like a sensible analogue to space traffic control for obvious reasons—namely, that it’s about the prevention of collisions—it is actually an inappropriate model, and that maritime law actually provides a better one. 

All of the world’s international airspace is designated to a single entity state for the purposes of providing air traffic control services. So, for example, the US controls 5 million square miles of domestic airspace but 24 million square miles of international airspace. They are the sole authority to provide those air traffic control services in that airspace by virtue of the ICAO [International Civil Aviation Organization]. 

Space doesn’t have anything like that. But the high seas don’t have that either. What the high seas have is a collection of agreed-upon rules of behavior and the authority over each vessel: the state under which the vessel flag is flown. There’s not a high-seas authority that says yes or no, you can operate here and you can’t operate here. Everyone has access to this shared resource, and the principles of freedom of the sea include the freedom of navigation, freedom of overflight, freedom to lay cables underneath, freedom of fishing. Within the maritime agreements, there is freedom to conduct commercial activities. This is different from airspace, which historically has been an area purely for transportation. 

The orbital domain is not solely for transportation [either]. It’s the domain in which the commercial activity occurs: telecommunications, remote sensing, etc.

Of course, maritime law is also meant to prevent collisions on the high seas. Collision regulations, or colregs, dictate what’s supposed to happen if two vessels are [on course for] a head-on collision: who has priority to maneuver, what to do if something happens in a narrow channel … These sort of principles are laid out very clearly. They have very clear applicability to the challenges we’re facing in the space domain. There are very clear parallels. Whereas if we take the aviation model, we’re really trying to force a square peg into a round hole.

Is there pushback or disagreement on the idea of using maritime law as the inspiration for space law? Is the general consensus moving toward this idea?

I think it’s trending that way, by virtue [of the fact] that it’s really the only viable path forward, but there is always discussion. Having someone or some singular body decide what we can do is not a realistic outcome, given the nature of the space domain. We don’t do space traffic like air traffic because it’s not simply a safety question. It is a diplomatic question and an economic question as well. 

Giving control of space traffic to one regulatory body would be easy, like the 18th Space Control Squadron, which provides these services free of charge. But there are countries that are suspicious of that [idea]. And then, of course, there is the issue of classified data. So you get into these complexities of trust—you know, if there was one trusted global entity, then sure, we could do that. [But] there aren’t any that are trusted by all, and trust is something that changes over time. 

So the path forward is to create a way for that information to be shared and trusted. For example, I’m working on a project where we’re talking about blockchain as an enabler for trusted information sharing. By nature of the blockchain, you can determine who inputted the information and validate them as a legitimate participant, and that information can’t be altered by a third party. 

Space is often described as a new kind of Wild West—lawless and unregulated, and anything goes. How can a framework for something like space traffic management even get established if there’s also just no set pathway for establishing rules to begin with? 

I would argue that space isn’t actually the Wild West. There is an obligation in the 1967 Outer Space Treaty for states to supervise objects that they permit to launch from their countries. So it’s not unregulated; it’s not completely free. It’s just we haven’t agreed on what that actually means for continuing supervision. 

The Iridium-Cosmos accident was a wake-up call. It sparked a lot of activity, like the development of on-orbit servicing technology to dispose of big objects that remain in space, and also the development of commercial sensor networks so that we can have better and better space situational awareness information. 

The next big catalyst, I believe, is megaconstellations. We’re seeing more [potential collision] alerts between two maneuverable satellites, which is a solvable problem if we have a set of rules. This creates a lot of pressure on the system to start reaching these agreements. Capitalism is a pretty effective motivator. When people see more and more economic opportunities in popular orbits, then balancing access to those orbits becomes a motivator as well.

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