NASA tests spacecraft navigation without GPS

NASA is testing technology that could allow spacecraft to navigate autonomously without relying on GPS or continuous instructions from Earth. The technology is being demonstrated by Starling, a group of four CubeSats operating in low Earth orbit.

The Starling mission is designed to show how multiple small spacecraft can operate as a coordinated swarm. The satellites communicate directly with each other, share information and can make decisions without requiring every action to be commanded from the ground.

One of the key technologies is StarFOX, which uses optical sensors to determine the position of the spacecraft and identify other objects in orbit. The system can track multiple members of the swarm simultaneously and calculate their orbits using measurements between the spacecraft and observations of stars.

This is important because GPS is not available everywhere in space. NASA therefore wants to develop navigation systems that can function independently, particularly for missions far from Earth. During the Starling experiments, the spacecraft demonstrated relative navigation without GPS. 

NASA is also testing Distributed Spacecraft Autonomy (DSA), software that effectively gives the swarm a shared decision-making capability. Each spacecraft contributes its own observations and status information, after which the system determines how the group should respond. This can reduce the amount of work required from operators on Earth. 

The technology could eventually be useful for missions around the Moon and farther into deep space. NASA has already tested the concept in simulations involving lunar orbits, including scenarios with swarms of up to 60 spacecraft. Such networks could eventually provide navigation and timing services around the Moon in a similar way to GPS on Earth.

The advantage of autonomous navigation becomes particularly clear as spacecraft travel farther from Earth. Communication delays can make real-time control impossible, while autonomous systems can respond immediately to changes in their surroundings.

NASA sees Starling as an early step toward larger groups of spacecraft that can navigate, communicate and coordinate their activities independently. The technology could support future scientific missions and exploration beyond Earth while reducing dependence on ground-based navigation and communication infrastructure.