A new type of electric propulsion system has successfully fired in orbit, potentially opening the door to cheaper, simpler and more scalable propulsion for the growing satellite industry.
Muon Space has announced the first successful in-space firing of a zinc-fueled Hall-effect thruster, marking a major milestone for electric propulsion technology. The company’s Starlight thruster used solid zinc as its propellant and successfully completed its maiden orbital firing aboard SERT-III, a spacecraft built specifically to test the technology.
The historic test took place on July 1, 2026, and the thruster worked successfully on its very first attempt. According to Muon Space, telemetry collected during the firing closely matched predictions from ground testing, while orbital tracking confirmed that the spacecraft experienced measurable thrust.
The demonstration could be especially important for the rapidly expanding satellite-constellation industry, where companies are looking for propulsion systems that are efficient, affordable and easier to manufacture and operate at large scale.
Why Hall-Effect Thrusters Matter
Satellites need propulsion for several important tasks. They may need to raise their orbit after launch, maintain their position, avoid collisions, or eventually move into a lower orbit for disposal.
Traditional chemical rockets can provide strong thrust, but they consume propellant relatively quickly. Electric propulsion takes a different approach. Instead of producing a powerful burst of thrust, electric thrusters generate much smaller amounts of thrust over long periods.
One of the most widely used forms is the Hall-effect thruster (HET).
Hall-effect thrusters use electricity and a magnetic field to accelerate charged particles out of the engine. The particles leave the spacecraft at very high speed, producing thrust in the opposite direction.
This gives electric propulsion a major advantage: high propellant efficiency.
However, conventional Hall-effect thrusters commonly use noble gases such as xenon or krypton. These gases need to be stored under high pressure, which requires tanks and additional spacecraft hardware. The propellant itself can also be expensive and subject to supply-chain limitations.
Muon Space is attempting to change this equation by replacing those gases with solid zinc.
Why Zinc Could Make Satellite Propulsion Simpler
At first glance, using a metal as rocket propellant may sound unusual. But zinc has several properties that make it attractive for this application.
Zinc is relatively abundant, inexpensive and non-toxic. Most importantly for spacecraft design, it is solid at room temperature.
That means zinc does not need to be stored inside a high-pressure gas tank like xenon or krypton.
Instead, the solid material can be stored and fed into the propulsion system, where it is heated and vaporized before being used to generate the plasma needed for the Hall-effect thruster.
Removing high-pressure storage could simplify several parts of a spacecraft.
It could reduce the complexity of propellant storage, make ground handling easier and potentially simplify launch integration. For companies building dozens or hundreds of satellites, even relatively small reductions in cost and complexity can become significant when multiplied across an entire constellation.
The technology also reduces reliance on noble gases, which have become an important concern as the number of satellites being launched continues to grow.
The First Firing Was More Than a Thruster Test
The July 1 demonstration was designed to test much more than whether the thruster could simply turn on.
Muon Space built SERT-III, a dedicated propulsion test spacecraft, specifically to evaluate the Starlight system in the real space environment.
Before the spacecraft was launched, the company conducted extensive testing in vacuum chambers. Multiple flight-representative thrusters were tested under different operating conditions, including different throttle levels, temperatures and start-up cycles.
These tests created a baseline for comparison.
Once Starlight reached orbit, engineers could compare the spacecraft's actual performance with what they had observed on Earth.
The results were encouraging.
Telemetry showed that the thruster started and completed its burn successfully. The spacecraft also did not experience harmful effects from electromagnetic interference, sudden power changes or interactions with the plasma produced by the thruster.
Most importantly, orbital tracking detected a clear change in the spacecraft's orbit, providing direct evidence that the thruster generated the expected thrust.
Can Solid Zinc Really Work in Microgravity?
One of the biggest questions before the mission was whether solid zinc could be reliably handled and vaporized in the unusual environment of space.
On Earth, engineers can control equipment under familiar conditions. In orbit, however, microgravity can affect how materials move and behave.
The SERT-III mission provided a real-world test.
According to Muon Space, the flight demonstrated that the solid zinc propellant could be fed and vaporized reliably in microgravity.
The mission also studied another important issue: contamination.
Any propulsion system can potentially release material that deposits on nearby spacecraft surfaces. For satellites carrying sensitive cameras, sensors, solar panels or communications equipment, unwanted deposits could become a serious problem.
To study this, SERT-III carried Thermoelectric Quartz Crystal Microbalance (TQCM) sensors positioned around the spacecraft.
These instruments monitored how much zinc was deposited near the thruster.
The measurements showed that zinc deposition was below the conservative predictions made before the mission. This gives engineers additional information for improving their models and designing future systems to manage the plume.
Performance Matched Ground Testing
Another important result came from comparing orbital data with laboratory testing.
Muon Space reported that the in-space telemetry was consistent with the company's ground-test results. Initial analysis also indicated that the system was meeting or exceeding its design targets for thrust and efficiency.
This is important because a propulsion system can behave differently once it leaves a controlled laboratory environment.
The successful test therefore represents an end-to-end validation of the technology—not simply a demonstration that the engine can operate in a vacuum chamber.
The spacecraft, power system, propellant feed system and thruster all had to work together in orbit.
What This Could Mean for Satellite Constellations
The potential impact of the technology becomes clearer when looking at the rapidly growing number of satellites being deployed.
Large constellations can require dozens, hundreds or even thousands of spacecraft. Every satellite needs power, communications and, in many cases, propulsion.
Traditional propulsion systems can add significant cost and complexity to every spacecraft.
A zinc-based Hall-effect thruster could potentially provide the efficiency of electric propulsion while making propellant storage and spacecraft integration simpler.
Starlight is designed for missions including orbit raising, station keeping and deorbiting, making it potentially useful across several stages of a satellite's operational life.
If the system can be manufactured reliably at scale, its relatively inexpensive propellant could also help reduce the cost of operating large satellite fleets.
What Happens Next?
The successful SERT-III mission is an important milestone, but it is not the final step.
Muon Space plans to use the data collected during the orbital test to improve the Starlight system's reliability, manufacturing process and plume management.
The company says it plans to begin deploying the current-generation Starlight thruster on customer missions before the end of 2026.
Muon is also developing a second-generation version called Gen2. This system is intended to provide a wider range of thrust for larger spacecraft.
The company plans to conduct the first orbital test of Gen2 in the first quarter of 2027, followed by its first commercial customer mission later in 2027.
A New Direction for Electric Space Propulsion
The successful firing of Starlight does not mean zinc will immediately replace xenon or krypton across the satellite industry. Future missions will still need to demonstrate long-term reliability, manufacturing at scale and performance across different spacecraft and mission profiles.
But the first orbital demonstration is a significant step.
For decades, electric propulsion has offered satellites an extremely efficient way to maneuver through space. The challenge has often been the cost and complexity of the propellant systems supporting those engines.
Muon Space's zinc-powered Hall-effect thruster takes a different approach: use a common solid metal instead of relying on pressurized noble gases.
The successful first firing shows that the concept can operate in the real space environment.
If future missions confirm its reliability and economics, solid-zinc propulsion could become an important new option for the next generation of commercial satellites—and potentially make sophisticated electric propulsion more accessible as satellite constellations continue to expand.
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