Superconducting actuator reaches flight readiness aboard Starburst-1

Portal Space Systems’ first free-flying mission with live payloads now carries a device built to steer it without spending chemical propellant. Zenno Astronautics has completed and integrated its Supertorquer aboard Portal Space Systems’ Starburst-1, which is moving through final flight preparations.

The actuator uses superconducting electromagnetics to control a spacecraft’s attitude—its orientation. It creates a magnetic dipole of up to 3,500 A·m², then interacts with Earth’s magnetic field to provide control authority in medium Earth orbit and geostationary Earth orbit. Unlike a chemical thruster used for pointing, it does not consume a propellant reserve.

That distinction matters for Starburst-1’s mission. Portal designed the spacecraft for rendezvous and proximity operations, rapid retasking and rapid orbital change for national-security and commercial operators. If the actuator handles attitude control as intended, propellant can remain available for the maneuvers that actually move the spacecraft, rather than being spent on keeping it pointed.

The same magnetic field may offer a second benefit: reducing the radiation reaching onboard systems by deflecting some charged particles. Zenno’s laboratory testing has shown promising results, but the company has not yet demonstrated that effect in orbit. Starburst-1 will carry a charged-particle counter specifically to measure it.

And so, concretely, the near-term result is a flight test of a new control method on a maneuverable spacecraft—not a finished replacement for propulsion. Starburst-1 will also validate subsystems shared with its larger Supernova trans-orbital vehicle, including high-performance reaction-control-system thrusters, while the Supertorquer’s expected status as the most powerful magnetic actuator flown will still depend on the mission taking place.