WASHINGTON — As companies develop plans for large constellations of orbital data center satellites, experts say now is the time to start thinking about some critical space safety topics and rules of the road.
During a July 29 panel discussion organized by the Secure World Foundation, government and industry officials said plans to deploy constellations of tens of thousands to a million satellites require coordination on how those systems can safely coexist in low Earth orbit.
Ezra Feilden, co-founder and chief technology officer of Starcloud, a startup that has filed plans for an 88,000-satellite constellation, said the best practices established by SpaceX’s Starlink constellation should be a good starting point.
“They’re operating essentially without any major safety issues,” he said, calling Starlink “a good example for the industry to follow regarding conjunction avoidance, beginning-of-life, end-of-life” satellite operations.
However, Starlink has only about 10,000 operational satellites, 1% the size of SpaceX’s proposed orbital data center constellation. That could mean far more potential conjunctions for operators to deal with.
“In the current constellations, there are hundreds of thousands of maneuvers that are done annually,” said Ron Birk, principal director of The Aerospace Corp.’s Space Enterprise Evolution Directorate. “In an environment with up to a million spacecraft, that could be more like half a billion maneuvers.”
Feilden noted that those studies assume the number of conjunctions will scale by the square of the number of satellites, which holds for systems where satellites are in intersecting orbital planes. That is not the case, though, for many orbital data center constellations, which propose to operate satellites in shells of dawn-dusk sun-synchronous orbits that do not intersect.
That would enable a much higher density of satellites, he argued, without increasing collision risks. “I think we should start to look at it in a similar vein that we treat geostationary orbit,” he said, “which requires a different framework to coordinate.”
That approach, though, comes with a caveat. All the orbital data center satellites in those dawn-dusk orbits need to orbit in the same direction. “If we all choose just one or the other, then all the traffic flows together,” he said.
The risk of collisions greatly increases, though, if some satellites orbit in one direction and others in the opposite direction. “It’s going to be like a highway without deciding which side of the road the traffic goes on, with an enormous number of head-on collision risks,” he warned.
That will require a “significant amount of coordination,” he acknowledged. “We don’t have any concrete suggestions for how to achieve that.”
One way is through space traffic coordination systems, which could help set global standards. Jeff O’Neil, director of government affairs at Planet, compared ongoing efforts at the Commerce Department to set up the Traffic Coordination System for Space, or TraCSS, with the development decades ago of a global air traffic control system promoted by the United States, sharing information that can help set standards.
“It’s a perfect example of how we can set the right rules of the road for everyone,” he said.
That could feed into regulatory efforts, such as the mission authorization system called Space Commerce Certification that the Office of Space Commerce is establishing to ensure compliance with the Outer Space Treaty, said Matias Cava, national space policy lead in the office.
However, the office only recently announced it was moving ahead with that certification system, which remains voluntary. “I would encourage operators to not wait for government action to develop and abide by best practices,” he said, “and think about how they would want their competitors to act in space.”
For Feilden, that means one thing. “Today, we need to decide which side of the road we’re going to be driving on.”
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