Duplicating expensive resources is expensive and wasteful, and most people would agree it’s unnecessary. However, the planned increase in major satellite constellations is currently causing a massive duplication of resources as individual companies and even countries try to set up their own infrastructure in space. What’s more, there is a relatively limited amount of space in Low Earth Orbit (LEO), where many of these satellites are supposed to go – any more than that and a single collision could cause Kessler Syndrome, where many of the ones already in orbit would be destroyed and we wouldn’t be able to launch any more for a long time. A new paper from researchers at the National University of Defense Technology in China suggests an alternative to these multiple megaconstellations – a single, modular system similar to how cloud computing works on the current internet.
According to paperwork filed with the International Telecommunications Union (ITU), there are more than 1 million satellites planned for launch in the future. Many will be used to complete three different communications megaconstellations – Starlink (SpaceX), Project Kuiper (Amazon), and OneWeb. Each of these megaconstellations don’t work well with each other, and have their own protocols and requirements that make intercommunication difficult at best.
Though admittedly not all of those satellites would launch of an LEO orbit, maintaining a safe distance in between them in that orbit would be extraordinarily difficult with that many satellites. A calculation from a different paper estimates that the total maximum safe amount of satellites LEO can hold is 175,000, assuming that they maintain a safe 50 km distance from one another.
Fraser talks about the impact Starlink is already having on astronomy.
The solution, the authors suggest, is an Open and Shared Sustainable Mega-Constellation (OSSMC). This would standardize the satellites used in constellations and make them interchangeable as well as interoperable. By their calculation, this would improve the satellites operational functionality while also limiting the number necessary to under 50,000 – well below the safe threshold for LEO satellites.
To implement this system, the authors suggest two new architectural innovations. First is a “Sensors+Network+AI” (SNAI) infrastructure, which abstracts the satellite’s operations out into three core elements. Sensors would be the things that detect the satellites surroundings, network is what allows it to communicate with other satellites, and AI in this case is the brute computational force it can use to process the necessary information. Ultimately, this flexibility allows the satellite to become a node in a larger network, interchangeable with many others.
That is where the second architectural innovation comes in. It is a “Cloud-Pool-Terminal” paradigm. In this case, each satellite acts like a node in a cloud, and when its computational resources aren’t being used, it can contribute to a “pool” of computing resources available for users on the ground, who interact with it via a “terminal”. All of this terminology is familiar to networking experts, as much of it mimics how cloud systems currently operate today. Except maybe it needs a different name since this one would actually be operating above the clouds.
People were even concerns about space junk when SpaceX first started launching Starlinks, as Fraser shows.
Anyway, the authors aren’t just putting this forward with no evidence – they compared how their architecture would work compared to existing ones. First, it lowers both the “Orbit Impact Score” and the space volume collision rate, both of which measure the chances of an impact between satellites, by double digit percentages. Another metric, as always, is cost, which the authors assess to decrease by 19.15%, while still increasing another metric – the Geometric Dilution of Precision, a measure of positional accuracy, by 51.07%.
A slightly more confusing metric is the “task success rate”, which they measured to have increased from 26 to 45%, as well as the “task failure rate” which they said decreased from 51% to 1%. To be clear, the original numbers were calculated using the authors’ own “semi-physical simulation experiments”, and don’t seem to represent the actual failure or success rates of any of the major constellations in use today.
So while this might sound like a good idea in practice, there’s one major thing working against it: geopolitical tensions. America and many of its allies, which control the current crop of megaconstellations, have already banned communications devices by Chinese manufacturers like Huawei due to security concerns. And given the important role Starlink has played in the ongoing Russia/Ukraine war, the likelihood of the world coming together to create a shared infrastructure that could also potentially benefit an enemy is unlikely to say the least. But, if the world itself ever moves towards a more stable and peaceful paradigm, there is the chance that we might see something akin to this shared, open source system. Just don’t hold your breath.
Learn More:
EurkeaAlert / Science China Press – Addressing the dilemma of one million satellites: a Chinese solution to alleviate orbital congestion in space
J. Yang et al – Open and Shared Sustainable Mega-Constellation
UT – China’s ‘Thousand Sails’ Joins Starlink as the Latest Mega-Satellite Constellation in Orbit