NASA's Starling Mission Demonstrates GPS-Free Satellite Navigation

NASA's Starling mission has reached another milestone, demonstrating a system that lets a spacecraft calculate its orbital position by observing other objects in space, rather than relying on an outside navigation network. The technology, called FALCON (Fast Autonomous Lost-in-space Catalog-based Optical Navigation), is a joint flight experiment developed by NASA and EraDrive, a startup that grew out of Stanford University.

Satellites near Earth use GPS to navigate, but GPS signals weaken and become unreliable or unavailable around the Moon and in deep space. FALCON offers an alternative: it uses Starling's onboard star tracker cameras, instruments that normally help a spacecraft determine its orientation, to spot other spacecraft and orbital debris nearby. It then matches what it sees against a catalog of known space objects and uses those matches as reference points to calculate its position.

In one test, mission controllers loaded a catalog of about 20,000 space objects and their predicted orbits onto Starling. FALCON compared the catalog data with its camera observations, calculating Starling's position while also refining the estimated locations of other objects. Over three days, and without any intervention from ground controllers, FALCON improved the known orbits of more than 200 objects, producing estimates more precise than the existing catalog. NASA said this marks the first time a spacecraft has determined its orbit using optical cameras and its position relative to other objects.

“FALCON is yet another success for the Starling demonstration mission,” said Roger Hunter, program manager for NASA's Small Spacecraft and Distributed Systems program at NASA's Ames Research Center in California's Silicon Valley. “The results from FALCON can have far-reaching implications for on-orbit space-traffic monitoring, collision avoidance, and alternative navigation.”

FALCON began as a University SmallSat Technology Partnerships project before developing into EraDrive, which is now commercializing its Era-Core flight software. Starling, which launched in 2023, will expand the FALCON experiment later this year, when its four spacecraft share tracking observations to refine their positions.