Thruster breakthrough? New 2-in-1 propulsion system is about to get an in-space test

Instead of having separate fuel for chemical thrusters and electrical thrusters, a Massachusetts Institute of Technology (MIT) study suggests that a single propellant can power both kinds of systems. And this idea will get an in-space test soon, if all goes according to plan. "If you can have chemical and electrical propulsion in one small package, it's the best of both worlds," Amelia Bruno, a former postdoctoral student at MIT who led the new study, said in a university statement on Monday (June 1). "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." The study borrows from fuel research by the U. Air Force, and it was partially funded by NASA. The space agency's Green Propulsion Dual Mode cubesat spacecraft will launch no earlier than November to see if the propulsion system and monopropellant, already tested on the ground, also works well in space. The mission to low Earth-orbit will serve as a valuable demo, the agency stated, for missions that go much farther from our planet — to places such as Mars, the eventual destination for human missions under NASA policy. "NASA is looking to expand deeper into space to support future agency objectives. Major drivers for these activities include researching and developing new and advanced propulsion systems and capabilities," agency officials wrote of the cubesat mission, which last year was expected to launch in October 2025, according to a SpaceNews report. The green monopropellant the mission is using, tested in a new MIT study in the Journal of Propulsion and Power, builds upon previous Air Force research. The propellant is called ASCENT, or Advanced Spacecraft Energetic Non-Toxic Propellant. The fuel is marketed as greener, or less toxic, than the usual high-efficiency hydrazine that is perfect for making big maneuvers in space but is dangerous to handle. It's also been tested in space before, during NASA's Green Propellant Infusion Mission in 2019-20 (when the fuel was called AF-M315E; it has since been renamed, according to the Air Force Research Laboratory, which developed it). What's more, ASCENT — despite being originally envisioned for chemical thrusters that use fuel quickly, during big space moves like orbital insertions — may also be suitable for electrospray thrusters. These thrusters are designed to make smaller, long-term adjustments to a spacecraft's trajectory. The tiny (thumbnail- to dime-sized) thrusters use an electric field to accelerate particles of liquid propellant.