Ion thrusters are today the most common prime mover for powering satellites during orbital maneuvers.
But traveling from low Earth orbit (LEO) to more distant orbits – or even to the Moon – requires a different type of ion thruster capable of escape velocity and orbital capture maneuvers.
Using technology originally developed for NASA’s upcoming lunar space station, the space agency has miniaturized its high-power solar electric technology into an engine that could make more complex satellites and planetary missions possible.
The history of space travel is filled with impressive sizzling spools of fire-breathing chemical engines launching monumental rockets skyward to the Moon, Mars and beyond. Although these massive devices are marvels of human engineering, the real workhorses of the space industry are the much less gargantuan ion thrusters.
These engines are as old as rockets themselves…Soviet and German rocket leaders imagined their future uses more than a century ago. And today, these electric propulsion systems power the swarms of satellites around Earth that make modern life possible. Unlike chemical rockets that release gases for propulsion, ion engines are powered by individual atoms, making them much more fuel efficient and allowing satellites to operate longer.
However, they are not perfect. In the future, spacecraft will need to perform high-speed propulsion maneuvers, such as achieving escape velocity and orbital capture, which current ion engines cannot provide. That’s why NASA developed the H71M sub-kilowatt Hall Thruster, a next-generation ion engine capable of providing speed change.
The propulsion system must operate at low power (sub-kilowatt) and have high propellant flow (i.e., the ability to use a high total mass of propellant over its lifetime) to allow the impulse required to execute these maneuvers. Although commercial ion thrusters are sufficient for most LEO satellites, these engines use only “10 percent or less of the initial mass of a small spacecraft in propellant,” according to NASA. The H71M thruster uses 30% and could operate for 15,000 hours.
“Small spacecraft using NASA-H71M electric propulsion technology will be able to maneuver independently from low Earth orbit (LEO) to the Moon or even from geosynchronous transfer orbit (GTO) to Mars,” wrote the NASA on its website about the new one. ion thruster. “The ability to conduct missions from these near-Earth orbits can significantly increase the throughput and reduce the cost of science missions to the Moon and Mars.”
The creation of this thruster grew out of NASA’s work on the power and propulsion element of Gateway, NASA’s planned lunar orbital space station. The team essentially miniaturized the high-power solar electric technologies that will make this lunar mission possible into a package that can provide thrust for smaller space missions.
One of the first spacecraft companies to use this next-generation technology is SpaceLogistics, a space subsidiary of Northrop Grumman. The company’s NGHT-1X Hall thrusters are based on NASA technology and will enable its Mission Expansion Module (MEP) – which, as the name suggests, is essentially a satellite repair vehicle – to reach geosynchronous Earth orbit, where it will attach to a larger satellite. Acting as a “propulsion pack,” the MEP will act as an ion-powered symbiote that will extend the larger satellite’s mission by at least six years.
If all goes well, this small but powerful thruster could enable planetary missions once thought impossible.
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