A space vessel is traveling through the vastness of space using ion propulsion, leaving a trail of blazing light in its wake. This illustration by Corey Ford from Stocktrek Images depicts the futuristic spacecraft in all its glory.
Currently, ion thrusters are the prevailing main mechanism used to propel satellites during orbital maneuvers.
However, in order to journey from low-Earth orbit (LEO) to more distant orbits, including the Moon, a specialized type of ion thruster is necessary to reach escape velocity and perform orbital capture maneuvers.
By leveraging advancements made for NASA’s upcoming lunar space station, the agency has successfully reduced the size of their high-power solar electric technology to create an engine that could enable more intricate satellite and planetary missions.
The past of space exploration is packed with remarkable videos showcasing powerful chemical engines propelling enormous rockets upwards towards the Moon, Mars, and other distant destinations. Despite the impressive nature of these colossal machines, the true driving force of the space sector are the significantly smaller ion thrusters.
The origins of these engines date back to the early days of rocketry, when Soviet and German leaders envisioned their potential uses over a century ago. Today, these electric propulsion systems are responsible for powering the numerous satellites orbiting Earth, which play a crucial role in modern society. Unlike traditional chemical rockets that emit gases for propulsion, ion engines utilize individual atoms as their power source, making them significantly more efficient in terms of fuel consumption and enabling longer operation periods for satellites.
Despite their capabilities, there are still flaws with current spacecraft technology. In the near future, there will be a need for high-speed propulsion maneuvers, such as escaping Earth’s orbit and entering into orbit around other celestial bodies, that cannot be achieved by existing ion engines. As a solution, NASA has created the H71M sub-kilowatt Hall-effect thruster, a more advanced ion engine that is capable of providing the necessary velocity change.
The low-power (sub-kilowatt) operation and high-propellant throughput are essential for the propulsion system to achieve the necessary impulse for maneuver execution over its lifetime. While commercial ion thrusters are suitable for most LEO satellites, NASA states that these engines typically use only “10% or less of a small spacecraft’s initial mass in propellant.” In comparison, the H71M thruster uses 30 percent of the spacecraft’s initial mass and can remain operational for 15,000 hours.
According to NASA’s website, small spacecraft equipped with NASA-H71M electric propulsion technology will have the capability to independently move from low-Earth orbit to either the Moon or a geosynchronous transfer orbit to Mars. This new ion thruster will enable missions to be conducted from these near-Earth orbits, potentially increasing the frequency and reducing the expense of lunar and Mars scientific missions.
NASA’s development of this thruster was inspired by their work on the Power and Propulsion Element for Gateway, a planned lunar orbital space station. The team was able to shrink the high-power solar electric technologies used for the lunar mission into a compact package suitable for smaller space missions.