You could have a lot more flexibility to do a lot more things.
For decades, small satellites have faced a quiet but stubborn constraint: to move quickly and to move wisely required two separate fuel systems, two separate tanks, and a compromise between power and precision. A team at MIT, working with a propellant originally designed to make spaceflight safer, has dissolved that constraint — demonstrating that a single ionic liquid can feed both a chemical thruster and an electrospray thruster, giving even the smallest spacecraft the full range of motion once reserved for far larger machines. The first real-world test arrives this November, when NASA sends a briefcase-sized satellite into orbit carrying one shared tank and the ambitions of a much larger mission.
- Small satellites have long been forced to choose between raw thrust and fuel efficiency — a limitation that has quietly capped how far and how usefully they can operate.
- MIT researchers discovered that ASCENT, an Air Force-developed ionic liquid propellant, performs equally well in both chemical and electrospray thrusters, collapsing two systems into one shared tank.
- Lab tests ran up to 100 hours of continuous operation inside a vacuum chamber, with a CubeSat spinning on a magnetic levitation stand as engineers measured thrust and efficiency across both thruster types.
- NASA's Green Propulsion Dual Mode mission, launching in November, will carry the first shared-tank system into space — a live trial that could redefine what small satellites are capable of.
- If validated in orbit, the technology opens pathways to CubeSat missions targeting Mars and the asteroid belt, as well as more responsive Earth-observation constellations that can deploy and reposition on demand.
A team at MIT has solved a long-standing problem in small satellite design: the requirement to carry two entirely separate propulsion systems, each with its own fuel tank, each built for a different purpose. By working with a propellant called ASCENT — originally developed by the U.S. Air Force as a non-toxic replacement for the hazardous fuel hydrazine — the researchers showed that a single tank can power both a chemical thruster and a set of electrospray thrusters. The result gives tiny spacecraft the ability to perform hard, fast maneuvers and slow, precise adjustments from the same fuel supply.
ASCENT turns out to be an ionic liquid, a salt-based fuel that stays liquid even in the vacuum of space, which makes it naturally suited to both thruster types. Chemical thrusters provide raw acceleration — the kind needed to change orbits quickly. Electrospray thrusters, thumbnail-sized devices that use electric fields to accelerate charged particles, produce thrust with exceptional efficiency over long distances but cannot match a chemical thruster's sudden power. Until now, spacecraft designers had to carry both systems separately or sacrifice one capability entirely.
To verify ASCENT's dual-mode potential, the team filled small reservoirs — roughly the size of Lego bricks — with one gram of the propellant and mounted electrospray thrusters on opposite sides of a CubeSat. Inside a vacuum chamber on a magnetic levitation stand, they applied varying voltages and watched the satellite spin as the thrusters fired. Across experiments lasting up to 100 hours, ASCENT matched the performance of conventional ionic liquids, confirming that no compromise was required.
The first orbital test arrives this November with NASA's Green Propulsion Dual Mode mission — a briefcase-sized CubeSat drawing one chemical thruster and four electrospray thrusters from a single shared tank. Success could open the solar system to small satellites in ways previously unimaginable: efficient electrospray cruising toward Mars or the asteroid belt, with chemical thrusters ready for quick repositioning when something worth observing comes into view. A simple idea — one tank, two modes — took years of collaboration between MIT, the Air Force, and NASA to make real.
A team at MIT has cracked a problem that has long constrained the ambitions of small satellites: the need to carry two entirely separate propulsion systems, each with its own fuel tank, each optimized for a different job. Now, working with a special propellant developed by the U.S. Air Force, the researchers have shown that a single tank can power both a chemical thruster and a set of delicate electrospray thrusters—giving tiny spacecraft the ability to perform both the hard, fast maneuvers of a rocket and the slow, precise adjustments of a fuel-efficient ion engine.
The propellant is called ASCENT, short for Advanced SpaceCraft Energetic Non-Toxic propellant. It was originally designed as a safer alternative to hydrazine, the traditional fuel for chemical propulsion in space, which is notoriously hazardous to handle. What the MIT team discovered is that ASCENT happens to be an ionic liquid—a salt-based fuel that remains liquid even in the vacuum of space—which means it can do double duty. Amelia Bruno, a former postdoctoral researcher in MIT's Department of Aeronautics and Astronautics and the lead author of a new study in the Journal of Propulsion and Power, puts it simply: "If you can have chemical and electrical propulsion in one small package, it's the best of both worlds."
The implications ripple outward quickly. Small satellites, or CubeSats, are already cheaper and easier to launch than their larger cousins. But they have always been constrained by their size—everything must be miniaturized, including fuel supplies. A chemical thruster gives you raw power for quick burns: ascending, descending, speeding up, slowing down. An electrospray thruster, by contrast, is a thumbnail-sized device that uses an electric field to accelerate charged particles from an ionic liquid, producing a fine spray that generates thrust with remarkable efficiency. It can nudge a spacecraft across millions of miles, but it cannot produce the sudden acceleration a chemical thruster can. Until now, you had to choose. You had to carry both systems, or sacrifice capability.
To test whether ASCENT could truly power both types of thrusters, Bruno and her colleagues, including Paulo Lozano, the Miguel Alemán Velasco Professor of Aeronautics and Astronautics, filled small reservoirs the size of Lego bricks with one gram of ASCENT—a liquid with the viscosity of baby oil—and attached electrospray thrusters to opposite sides of a CubeSat. They placed the whole assembly on a magnetic levitation stand inside a vacuum chamber tuned to mimic the conditions of space. Then they applied varying levels of voltage and watched the CubeSat spin like a floating top as the thrusters fired. Over multiple experiments lasting up to 100 hours of continuous operation, they measured the thrust produced and calculated fuel efficiency. The result: ASCENT performed just as well as the conventional ionic liquids the team had been using, proving that a single propellant could indeed fuel both thruster types without sacrifice.
The real test comes this November, when NASA launches the Green Propulsion Dual Mode mission—a briefcase-sized CubeSat carrying one chemical thruster and four electrospray thrusters, all drawing from a single propellant tank. If successful, the mission will open doors that have been closed to small spacecraft. Lozano envisions CubeSats making the slow journey to Mars or the asteroid belt using their electrospray thrusters for efficiency, then switching to chemical thrusters for quick repositioning to observe interesting features. Closer to home, a constellation of small satellites could be deployed rapidly or slowly depending on what a storm or climate event demands. The flexibility changes everything. "You could have a lot more flexibility to do a lot more things," Lozano says. For the first time, a satellite will have a shared propellant tank—a simple idea that took years of collaboration between MIT, the U.S. Air Force, and NASA to make real.
Citas Notables
If you can have chemical and electrical propulsion in one small package, it's the best of both worlds.— Amelia Bruno, MIT Department of Aeronautics and Astronautics
You could send CubeSats to Mars or the asteroid belt, making the journey slowly with electrospray thrusters, then use chemical thrusters to quickly move and look at interesting features.— Paulo Lozano, MIT
La Conversación del Hearth Otra perspectiva de la historia
Why does it matter that both thrusters can use the same fuel? Couldn't you just carry two separate tanks?
You could, but then you're doubling your weight and your complexity. A CubeSat is already constrained by size and launch cost. Every kilogram matters. A shared tank means you're not paying twice for the infrastructure.
So this is really about efficiency—fitting more capability into something smaller?
Partly that. But it's also about flexibility. A chemical thruster is all-or-nothing. An electrospray thruster is all finesse. Before, you had to decide which one you needed. Now you can have both.
How did they know ASCENT would work in an electrospray thruster when it was designed for chemical propulsion?
They didn't, not for certain. But ASCENT is an ionic liquid, and ionic liquids are what electrospray thrusters are built around. Bruno says they realized the chemistry aligned and decided to test it. Sometimes the best discoveries come from noticing that two separate problems might share a solution.
What happens if this mission in November succeeds?
Then you start seeing small satellites doing missions that were previously impossible. Mars exploration with CubeSats. Real-time climate monitoring with rapid repositioning. The constraint that has always limited small spacecraft—the choice between power and precision—disappears.
Is there a risk that this becomes the standard and then everyone depends on it?
That's how good technology works. It becomes invisible because it's so useful. The real question is whether other teams can replicate it, whether it scales, whether it holds up over years in space. November will answer some of those questions.