Swarms of autonomously maneuvering satellites promise to make space operations far more efficient. But they also pose collision risks.
Through the Starling mission, NASA and SpaceX will begin testing strategies for preventing autonomous satellites from crashing into each other.
NASA originally planned to send the Starling mission into an orbital altitude of 555 kilometers. Because SpaceX Starlink broadband satellites operate in that orbit, the space agency’s Conjunction Assessment Risk Analysis (CARA) group advised Starling mission managers to send the four Starling cubesats 10 kilometers higher.
“Realizing that these two constellations are close to each other gave us an opportunity to look at how we will deal with space traffic management in the future, when there are even more spacecraft in low Earth orbit,” said Howard Cannon, NASA Starling project manager at the NASA Ames Research Center. “How can we avoid collisions given the number of spacecraft that will be up there?”
After Starling completes a six-month series of experiments to demonstrate swarm communications, navigation and autonomy, CARA, Starling and Starlink will test collision-avoidance strategies.
The spacecraft will report their positions to the ground systems.
“Then, conjunction-analysis software on the ground will automatically say, ‘Hey, you’re going to run into each other if you don’t do something,’” Cannon said.
The warning will be sent to the satellites, which will plan maneuvers. Before carrying out the maneuvers, though, the satellites will seek approval from the ground systems.
As traffic surges in low Earth orbit, this type of coordination will be essential.
“You can’t have humans in the loop,” Cannon said. “This is all going to have to be automatic in the future.”
Moriba Jah, an associate professor of aerospace engineering at the University of Texas at Austin, agreed.
“Most people don’t recognize that there is a data-pipeline problem in space,” Jah said. “There’s no way to downlink information from satellites to the ground fast enough to do the computations and send commands back to the satellites. There’s not enough time for that given the current infrastructure.”
By working together, Starling and Starlink will show how two constellations “can talk to each other and start playing out different criteria like right of way,” Jah said.
This article originally appeared in the June 2022 issue of SpaceNews magazine as “Starling meets Starlink.”
