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NASA and USAF-Backed Research Reveals the Breakthrough Propulsion Technology That Could Propell Future Satellite Swarms


In a University of Kentucky laboratory, three small spacecraft stand-ins slid across low-friction air tracks, nudging and pulling one another without thrusters, propellant, or physical contact.

Instead, they used carefully timed magnetic fields, a technique that could one day help future satellite swarms hold precise formations in space without constantly burning fuel.

The NASA and Air Force-backed study, set to be published in the September 2026 edition of Aerospace Science and Technology,  marks a step toward what researchers call electromagnetic formation flying, a proposed method for controlling the relative positions of satellites using onboard coils rather than conventional propellant-based thrusters.

In the study, researchers demonstrated a decentralized, three-satellite control system that used alternating magnetic field forces to maintain formation with centimeter-level precision, offering a possible pathway for future space telescopes, interferometers, gravity-wave detectors, and other distributed spacecraft missions.

“Spacecraft formation flying can advance a variety of space technologies such as distributed-aperture telescopes, gravity-wave detectors, and interferometers,” researchers write. “One challenge for spacecraft formation flying is that traditional propellant thrusters eventually deplete, and they can contaminate sensitive spacecraft components.”

The study, authored by scientists from the University of Kentucky’s Department of Mechanical and Aerospace Engineering, focuses on a longstanding problem in spacecraft engineering.

Many future missions may not rely on a single large spacecraft, but instead on groups of smaller satellites flying in carefully arranged formations. If those satellites can maintain their spacing and orientation with extreme precision, they could function together like a much larger scientific instrument.

For example, a distributed-aperture telescope could use multiple spacecraft separated by carefully controlled distances to achieve observing capabilities that might be difficult or impossible with a single monolithic telescope.

Similar formation-flying concepts have been proposed for space-based interferometers and additional missions in which the relative positions of spacecraft are central to mission performance.

However, keeping multiple satellites in formation is not easy. Standard spacecraft rely on thrusters, which consume limited propellant. Over time, that fuel runs out, limiting mission duration and maneuverability. Thruster plumes can also contaminate sensitive instruments, a concern on spacecraft carrying delicate optical, scientific, or electromagnetic sensors.

However, electromagnetic formation flying, or EMFF, offers a different possibility. Each spacecraft carries electromagnetic coils. When electric current flows through those coils, they create magnetic fields. Those fields interact with magnetic fields created by nearby spacecraft, producing attractive or repulsive forces that can alter the satellites’ positions relative to one another.

Put simply, the satellites can push or pull on each other using magnetism.

The idea is not entirely new. Previous work has explored electromagnetic formation flying between two spacecraft, including experiments using direct-current-driven coils.

The problem becomes much harder when the formation includes three or more satellites. In that case, every satellite’s magnetic field can interact with the others, creating a web of coupled forces that becomes increasingly difficult to control as the formation grows.

The new study approaches that problem using alternating magnetic field forces, or AMFF. Rather than driving the coils with steady direct current, the researchers use sinusoidal currents at specific frequencies.

The key insight is that two satellites generate a nonzero time-averaged interaction force only when their magnetic moments alternate at the same frequency. If they do not share a frequency, the average force between them is negligible.

That frequency-matching approach effectively allows the system to pair satellites electromagnetically. One pair can interact at one frequency, while another pair interacts at a different frequency.

By adjusting the amplitude of each sinusoidal signal, the satellites can control the strength of the force between each pair without requiring a centralized controller to solve the entire formation’s motion at once.

“Only pairs with a common frequency can generate a nonzero time-averaged intersatellite force, and that force is determined solely by the amplitudes at the common frequency,” researchers write. “The method in this paper is decentralized, which means that each satellite has access to measurements of its position and velocity relative to only its local neighbor satellites.”

Centralized control can work in smaller systems, but it can turn computationally clumsy as satellite formations grow. A scalable system would need each spacecraft to make local decisions based on nearby neighbors, rather than requiring a single controller to calculate every force across the entire formation.

To test the idea, the researchers built a ground-based experimental platform using three custom electromagnetic actuation system units placed on linear air tracks.

The air tracks allowed the units to move with low friction, simulating one-dimensional relative motion between satellites. Each unit included an electromagnetic coil, batteries, power electronics, an Arduino Due microcontroller, wireless communication hardware, and laser range-finding sensors for measuring relative position.

In the three-satellite setup, the center unit was driven by a sum of two sinusoidal currents, while each outer unit was driven by one of those frequencies. This allowed the center unit to interact independently with each outer unit, demonstrating the central premise of frequency-multiplexed magnetic control.

In closed-loop experiments, the three-satellite system achieved formation in less than 30 seconds. The maximum steady-state formation error was less than plus or minus 0.01 meters, or about 0.4 inches. The mean steady-state formation error was less than plus or minus 0.001 meters, or about 0.04 inches.

Those numbers demonstrate that the method did more than produce a magnetic tug in a lab. It allowed multiple units to settle into a desired formation using local feedback and alternating magnetic fields, while avoiding the coupling problem that has limited electromagnetic control for larger formations.

The researchers also compared the experimental results with computer simulations. While the simulations generally matched the observed behavior, the team noted some differences caused by real-world hardware factors, including sensor interference, current saturation, possible misalignment, airflow disturbances along the air tracks, and unmodeled magnetic effects.

Those caveats are important. This was not a spaceflight demonstration, and the system was tested only in one dimension. Real spacecraft would operate in a far more complex environment, where microgravity, radiation, extreme temperature swings, atmospheric drag in low Earth orbit, gravitational forces, Earth’s magnetic field, and equipment restrictions would all matter.

Researchers also note that traditional thrusters may still be needed for orbit maintenance, orbit transfers, or controlling the overall center of mass of a satellite formation.

In essence, this is not a replacement for all spacecraft propulsion. It is better understood as a possible propellantless method for controlling the relative positions of satellites once they are already in orbit and operating as part of a formation.

Still, that limitation does not diminish the possible impact. If electromagnetic formation flying can be scaled and adapted for real spacecraft, it could reduce propellant demands for future distributed missions. That could extend mission lifetimes, reduce contamination hazards to sensitive instruments, and enable spacecraft formations more flexible than today’s architectures.

The research was supported in part by the National Aeronautics and Space Administration (NASA), the National Science Foundation, and the Air Force Office of Scientific Research.

The funding mix reflects the dual scientific and strategic interests in the work. NASA has clear reasons to explore precise formation flying for future space observatories and scientific missions. The Air Force, meanwhile, has an obvious interest in satellite coordination, maneuverability, and resilient distributed space systems.

The study’s most intriguing contribution may be its demonstration that magnetic-field-based satellite control can be both decentralized and scalable.

Rather than treating a multi-satellite formation in a single complicated system that must be controlled from the top down, AMFF allows each satellite to manage interactions with its neighbors using assigned frequencies. That could become increasingly valuable as space missions move toward constellations, swarms, and distributed architectures.

Researchers caution that additional work will be needed to move beyond one-dimensional air-track experiments and toward three-dimensional testing, more realistic sensing and control hardware, and, eventually, on-orbit validation.

Additional coils would be needed for three-dimensional position control, and relative attitude control could require additional actuation frequencies for each interacting satellite pair.

Nevertheless, the laboratory results show that the underlying concept works in a three-body system, which is exactly where the hard part begins.

Two satellites can pull or push on each other relatively easily. Three satellites introduce the coupling problem that makes electromagnetic formation flying difficult. By demonstrating three-satellite control with alternating magnetic fields, the study delivers experimental evidence that the frequency-based solution can work.

For forthcoming space missions, that could be a meaningful step. The next generation of telescopes and orbital instruments may not always be built as single enormous spacecraft. They may be assembled virtually, with multiple satellites flying together as one coordinated machine.

If so, keeping those satellites precisely arranged without wasting propellant could become one of the enabling technologies of future astronomy, Earth observation, and national security space systems.

“This article presented a 3-satellite experimental demonstration of decentralized EMFF using AMFF,” researchers conclude. “The settling time and steady-state formation error achieved in these experiments demonstrate that this approach is most likely capable of meeting requirements for satellite constellation reconfiguration and maintenance, thereby addressing the need for propellant-free formation flying.”

Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan.  Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com 

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MIT Engineers Testing Exotic ‘Electrospray’ Propulsion for Faster, More Maneuverable Spacecraft


Massachusetts Institute of Technology (MIT) engineers are testing a new category of advanced-propulsion “electrospray” thrusters that combine the benefits of modern chemical and electrical thrusters used to drive satellites and other spacecraft into one hybrid system.

The team behind the novel propulsion technology said that electrospray thrusters could allow mission planners to design smaller, more nimble satellites and spacecraft capable of performing faster, more powerful maneuvers or slower, more precise adjustments, depending on mission requirements.

Electrospray Combines the Best of Chemical and Electric Propulsion

Launching rockets into space still requires chemical thrusters, but once spacecraft and satellites reach orbit, engineers continue to develop novel propulsion methods that are more efficient than chemical propulsion technologies. Given the strict weight requirements of spacecraft launches, finding alternatives to chemical propellants has opened up a wider range of mission profiles.

Among the most common alternatives to chemical thrusters are designs that combine electrical energy with small amounts of propellant to produce small but sustainable thrust. Although electric thruster designs require less fuel, saving significantly on launch weight, they also lack both the power and the rapid, quick burst performance of chemical thrusters.

According to study author Amelia Bruno, a former postdoc in MIT’s Department of Aeronautics and Astronautics (AeroAstro), combining chemical and electrical propulsion into a single system is “the best of both worlds.”

“This opens the door for small satellites to do even more science, more observations, and more interesting missions, all on a smaller and cheaper platform,” Bruno explained to MIT News.

Study co-author Paulo Lozano, the Miguel Alemán Velasco Professor of Aeronautics and Astronautics at MIT, agreed, noting that combining both technologies could enable a CubeSat mission to Mars “where they could make the journey slowly, using electrospray thrusters.”

“You could then use your chemical thrusters to quickly move to look at interesting features,” the professor added. “You could have a lot more flexibility to do a lot more things.”

ASCENT Rocket Fuel as the Thruster’s Ionic Liquid Propellant Enables Hybrid Design

According to a statement detailing the new electrospray thruster’s design, the ones developed by the MIT team are about the size of a thumbnail. Each thruster is also placed directly above a small fuel reservoir. For the MT electrospray thrusters, the fuel is an ionic liquid propellant, a liquid composed of salts that remain dissolved in a solution.

electrospray propulsion
These four flight-unit electrospray thrusters were delivered by the MIT Space Propulsion Laboratory to NASA for the upcoming Green Propulsion Dual Mode (GPDM) mission. Image Credit: Amelia Bruno

“Ionic liquids are very stable and can even remain a liquid in space, which not a lot of materials can do,” Bruno explained. “And it’s basically a sea of ions, which is why we base our technology around it, so we can pull those ions out into an electrospray.”

When a spacecraft’s battery delivers an electric charge to the fuel reservoir, the ions within the fuel also become charged. The thruster’s design channels the charged particles from the reservoir and through the thruster tips, expelling them into space.

Although the team has tested several types of ionic propellant in its electrospray propulsion thrusters, Bruno and Lozano have collaborated with the U.S. Air Force to synthesize an all-new ionic liquid propellant, which they are calling the Advanced SpaceCraft Energetic Non-Toxic propellant, or ASCENT.

Originally designed as a “green” alternative to extremely hazardous hydrazine rocket fuel that has been the staple in the rocket industry for decades, Bruno notes that ASCENT “happens to be an ionic liquid mixture.”

“And we said, hey, that’s the stuff we typically use,” the researcher added. “Theoretically, this should work. Let’s go figure out how.” 

Tests: Chemical Propellant Equally Efficient as Conventional Ionic Liquids

To test their electrospray design, each tested thruster was attached to a small reservoir about the size of a single Lego brick, and then the reservoir was filled with ASCENT. Next, electrospray thrusters were mounted on opposite sides of a traditional CubeSat.

To simulate the microgravity environment of Near-Earth Orbit, the team placed the thruster-equipped CubeSat on a MagLev stand. The team noted that the MagLev in Lozano’s lab is installed inside a large vacuum chamber. This design allows the researchers to fine-tune the environment to best mimic the conditions in space.

During a series of tests, the team applied varying voltage levels to the electrospray thrusters. As expected, the reaction produced a spray from the thruster nozzles, which spun the CubeSat around on the MagLev stand like a freely spinning top.

During each thruster firing, the team measured the amount of thrust produced. This data, combined with the voltage and fuel data, allowed the team to calculate ASCENT’s fuel efficiency during continuous operation. Some tests lasted up to 100 hours.

When the MIT group evaluated the results, they first determined that the choice of ASCENT was correct, as it successfully fueled each electrospray thruster. Even more significantly, the tests revealed that the readily available chemical propellant was equally efficient as conventional ionic liquids.

“Compared to our normal electrospray propellants, ASCENT can provide similar performance in terms of thrust,” Bruno explained. “Now that we know our thrusters work with ASCENT, we can start thinking of all the ways we can make them even better.”

Testing Electrospray Thrusters on NASA’s Green Propulsion Dual Mode Mission

When discussing the benefits of their successful electrospray thruster tests, Lozano noted that a spacecraft with electric and chemical thrusters can share a single fuel tank. Due to its compact design, this hybrid electrospray thruster could be mounted on a small satellite.

Fortunately, the team won’t have to wait long to see their thruster in action. According to the research team, whose work was partially supported by NASA, their design will be incorporated into NASA’s upcoming Green Propulsion Dual Mode mission scheduled to launch in November. The Green Propulsion Dual-Mode mission will carry a briefcase-sized CubeSat with a primary chemical thruster and specially designed electrospray thrusters, making it the first attempt to combine electrical and chemical propulsion in a small spacecraft.

“This will be the first time that a satellite will have a shared propellant tank,” Lozano explained.

Although a large portion of proposed electric propulsion missions that might employ the new electrospray thruster are designed to explore deeper into the Solar System and beyond, Lozano also highlighted the technology’s possible applications closer to home. For example, satellites equipped with both technologies could rapidly respond to environmental or climate changes in real time with a speed and efficiency unavailable with current propulsion options.

“Say there’s a storm coming, and you’d want to deploy your constellation of small satellites to observe over one location,” the researcher explained. “You could choose to send them quickly or slowly, depending on the nature of the observation.”

“And the only way to do that is if you have two propulsion systems, which is now possible,” he added.

Although the mission will not launch before November, Bruno noted that a successful test could allow engineers to consider missions they never thought possible.

“Now that we know our thrusters work with ASCENT, we can start thinking of all the ways we can make them even better,” the researcher explained.

The study “Performance Characterization of Electrospray Thrusters with Energetic Ionic Liquid Monopropellant” was published in the Journal of Propulsion and Power.

Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.

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NASA working to streamline development of nuclear electric propulsion demo mission

SR-1 Freedom

NASA is working on a streamlined management approach for a nuclear electric propulsion demonstration mission the agency wants to launch in two and a half years.

The post NASA working to streamline development of nuclear electric propulsion demo mission appeared first on SpaceNews.

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Blue Origin Rocket Blows Up on Florida Launchpad During Test

The rocket, built by the Jeff Bezos-owned space company, was to carry 48 satellites into space. Blue Origin reported on social media that “all personnel have been accounted for.”
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