Portal Space Systems Prepares Starburst-1 for Orbital Test of Superconducting Magnet

Portal Space Systems is preparing its Starburst-1 spacecraft for a late-2026 launch carrying a superconducting magnetic actuator designed to control spacecraft orientation without consuming conventional propellant. The Zenno Astronautics system can generate a magnetic dipole of up to 3,500 A·m² and is intended to demonstrate how Earth’s magnetic field could provide propellant-free attitude control while also allowing researchers to measure potential charged-particle shielding effects.

A Different Way to Move a Spacecraft

Most spacecraft rely on reaction wheels, magnetic torquers or thrusters to control their orientation.

Portal Space Systems is preparing to test another approach aboard Starburst-1: a superconducting magnetic actuator developed by Zenno Astronautics.

Rather than expelling propellant, the system generates a strong magnetic field that interacts with Earth’s magnetic field. That interaction produces torque, allowing the spacecraft to change its orientation.

The technology is particularly interesting for Portal because Starburst is being developed around a broader idea: spacecraft that can rapidly change their orbital position and respond to new mission requirements instead of remaining largely fixed in one orbit.

Starburst-1 Has Not Yet Launched

The underlying claim needs an important correction: Starburst-1 had not launched as of October 3, 2026.

Portal has manifested the spacecraft for a SpaceX rideshare mission and is preparing it for a Q4 2026 launch. Recent company and partner updates say the spacecraft completed vibration and final flight testing before heading toward the launch campaign.

That means the superconducting magnet’s performance in orbit remains a planned demonstration rather than a completed orbital result.

Portal’s Starburst-1 is an ESPA-class spacecraft designed for a one-year primary mission in sun-synchronous orbit. The company is targeting more than 1 km/s of total delta-v for the spacecraft’s broader maneuverability demonstration.

The Superconducting Magnet at the Center of the Mission

The payload comes from Zenno Astronautics and is called the Z01 Supertorquer.

Zenno says the system can produce a magnetic dipole of up to 3,500 A·m². The company describes it as the most powerful magnetic actuator expected to fly in space, while independent reporting has described the device as a superconducting magnet system intended for satellite positioning and precision interactions.

The key engineering idea is straightforward.

A current flowing through a coil generates a magnetic field. A conventional coil experiences electrical resistance, which produces heat and requires continuous power while the magnetic field is being maintained.

A superconducting coil behaves differently when cooled below its critical temperature. Its electrical resistance becomes extremely low, allowing very large currents to circulate with comparatively little resistive loss.

Zenno’s system uses high-temperature superconducting technology and a cryogenic cooling system to maintain the required operating conditions. Previous Z01 flight hardware has operated at approximately 77 kelvin, or about −196°C.

How Earth Becomes Part of the Control System

The magnet does not push directly against empty space.

Instead, it interacts with Earth’s magnetic field.

When the spacecraft’s magnetic dipole interacts with the planetary magnetic field, a torque is produced. That torque can rotate the spacecraft without firing a conventional thruster.

This is the same basic physical principle behind traditional magnetic torquers, but the superconducting approach aims to generate a substantially stronger magnetic dipole.

For a spacecraft that needs to change orientation frequently, the potential benefit is significant: some attitude-control functions could be performed without consuming the propellant that would otherwise be reserved for orbital manoeuvres.

Portal describes Starburst as a rapidly maneuverable spacecraft capable of rendezvous and proximity operations, rapid retasking and orbital changes.

Why Propellant-Free Attitude Control Matters

Spacecraft propulsion is often treated as the system that changes orbit, but propellant can also be consumed simply to control orientation.

If a spacecraft can perform some of those orientation changes magnetically, its propulsion system may be able to dedicate more of its available propellant and delta-v to actual orbital manoeuvres.

That does not make the spacecraft completely propellant-free.

Starburst-1 still uses conventional propulsion for translational manoeuvring. The superconducting system is being tested as an attitude-control technology and for precision interactions during close operations.

The distinction is important because magnetic torque generated through Earth’s field cannot simply replace orbital propulsion in every situation.

Its effectiveness also depends on the spacecraft’s orbit and the local magnetic environment.

The Magnet Could Also Test Radiation Protection

The Starburst-1 experiment has another scientific component.

A sufficiently strong magnetic field can influence the trajectories of charged particles. That raises the possibility of using magnetic fields as part of future spacecraft radiation-protection systems.

Portal CEO Jeff Thornburg has highlighted radiation shielding as a potential application of the magnet, while Zenno says Starburst-1 will carry a charged-particle counter to measure the effect directly in orbit.

This is still an experimental concept.

The mission is intended to provide empirical flight data rather than establish that the system can already protect an operational spacecraft from space radiation.

The measurements could help determine how useful strong localized magnetic fields might be for reducing exposure to charged particles around sensitive spacecraft hardware.

The Technology Already Has Some Flight Heritage

Starburst-1 is not the first time Zenno has put superconducting magnetic hardware into space.

In 2023, the company flew an early high-temperature superconducting electromagnet on a D-Orbit satellite carrier. That demonstration was primarily intended to establish that the technology could operate in space.

A later Z01 system flew aboard Impulse Space’s Mira spacecraft on the LEO Express 3 mission, where Zenno reported hundreds of hours of successful on-orbit operation and demonstrated commanded spacecraft-orientation changes.

Starburst-1 represents a larger and more capable application of the concept.

The planned mission will provide another opportunity to test the technology, this time on a spacecraft specifically designed around rapid orbital manoeuvrability.

Starburst Is Part of a Larger Space-Mobility Strategy

The superconducting magnet is only one part of Portal’s Starburst programme.

The company is developing Starburst as a maneuverable spacecraft bus that can operate in different orbital environments and support missions requiring rapid orbital changes.

Its larger Supernova spacecraft is being developed for trans-orbital operations, with Portal targeting a substantially higher delta-v capability. The two spacecraft share many systems and manufacturing processes, allowing flight experience from Starburst to feed into Supernova’s development.

Portal has also raised $50 million in Series A funding to accelerate its spacecraft and manufacturing programmes, including Starburst and Supernova.

What the Orbital Test Will Actually Prove

The upcoming mission should not be interpreted as proof that superconducting magnets can replace spacecraft propulsion.

Instead, Starburst-1 is designed to answer more specific engineering questions.

Can the superconducting system maintain its required thermal conditions in orbit?

Can it generate the predicted magnetic dipole?

Can it reliably interact with Earth’s magnetic field to control spacecraft orientation?

And can the magnetic field produce measurable charged-particle deflection under real orbital conditions?

Those measurements are important because space hardware must operate through vacuum, thermal cycling, radiation and long-duration exposure without the maintenance options available on Earth.

A New Control Layer for Maneuverable Spacecraft

If the technology performs as intended, superconducting magnetic actuators could become another tool in the spacecraft-control toolbox.

They would not eliminate chemical or electric propulsion. Instead, they could handle selected attitude-control functions while preserving propellant for manoeuvres that actually require translation.

The concept becomes particularly interesting when combined with highly maneuverable spacecraft.

Portal’s Starburst programme is built around rapid orbital response, while Zenno’s magnet attempts to provide a high-strength, propellant-free method of controlling orientation.

The upcoming Starburst-1 mission will therefore test more than a powerful magnet.

It will test whether superconducting electromagnets can become a practical control technology for a new generation of maneuverable spacecraft.

For now, the most important milestone is still ahead: getting the spacecraft into orbit and collecting the first long-duration flight data from the integrated system.

FAQs

What is Starburst-1?

Starburst-1 is an ESPA-class maneuverable spacecraft being developed by Portal Space Systems for a planned Q4 2026 mission demonstrating rapid orbital changes, retasking and rendezvous capabilities.

Has Starburst-1 launched yet?

No. As of October 3, 2026, Starburst-1 was still preparing for launch following final flight testing. Portal has targeted a Q4 2026 launch.

What does the superconducting magnet do?

Zenno’s Z01 Supertorquer generates a strong magnetic dipole that interacts with Earth’s magnetic field to produce torque, allowing spacecraft orientation to be changed without consuming conventional propellant.

How powerful is the Starburst-1 magnet?

Zenno says the Z01 system integrated on Starburst-1 can generate a magnetic dipole of up to 3,500 A·m².

Could the magnet protect spacecraft from radiation?

It may help deflect some charged particles, and Starburst-1 will carry instrumentation to measure that effect. However, the effectiveness of the technology as a practical spacecraft radiation shield remains an experimental question.