The electric propulsion technology evolves by eradicating those major problems through advanced simulation and innovative design. Such innovations are making the spacecraft mission coming outside of the Earth atmosphere more efficient, reliable, and long-term.
1. Ion Engine Breakthroughs
Electric propulsion, especially ion engines, has been identified as an efficient and low-fuel consumer compared to chemical rockets. In an ion engine, the gases such as xenon are ionized and expelled out at high speed to produce thrust. However, problems like electron back-scattering and degradation of components have posed a challenge to long-duration space missions.
Recently, research scientists at the University of Virginia and the University of Southern California published in Plasma Sources Science and Technology to better understand how electrons behave in an ion engine’s exhaust plume. Advanced supercomputer simulations help in analyzing thermodynamic properties that determine the velocity and temperature of particles in plumes.
2. Challenges in Electric Propulsion Systems
Although electric propulsion is very efficient, it has its own set of engineering challenges. One of the most important ones is back-scattering of electrons from the exhaust plume, which can cause damage to sensitive spacecraft components like solar panels and antennas.
Important challenges are:
Surface Erosion: Long-term exposure to ionized particles degrades spacecraft materials.
Energy Loss in Plumes: Electrons at the periphery of the ion plume lose energy much faster, which makes the interaction with spacecraft surfaces unpredictable.
Limited Thrust Capability: Though efficient, ion engines create much lower thrust than chemical propulsion, which is necessary to develop considerable speed over longer periods.
3. Solutions to Improve Ion Engine Performance
Advanced electric propulsion engineering solutions aim at overcoming these difficulties:
Improved electron confinement: scientists are refining methods of magnetic shielding and confinement, which spread the electrons outside the ion plume.
Plume Shaping Techniques: Altering the geometry of the ion beam is designed to reduce the back-scattering impact that imperils spacecraft components.
Alternative Propellants: Explorations into other ionizable gases, like krypton and iodine, are opening up the electric propulsion regime beyond the more conventional xenon-based thrusters.
4. NASA’s Advanced Electric Propulsion System (AEPS)
NASA is working with Aerojet Rocketdyne to develop the Advanced Electric Propulsion System (AEPS), which will be used to power deep-space missions. The system, which will use 50kW Hall-effect thrusters, will be critical to NASA’s Lunar Gateway, set to launch no earlier than 2027. AEPS will provide the following:
Improved thrust efficiency
Longer operating life
More efficient energy utilization for deep space
5. Innovative Spacecraft Designs for Electric Propulsion
The Aerospace Corporation is developing a new satellite design, called DiskSat, an alternative to the standard CubeSat. DiskSats are designed like flat plates, improving their surface area for solar energy generation, making them ideal for electric propulsion systems.
These are satellites 1-meter in diameter and about 2.5 cm thick.
Their design also improves maneuvering capability using ion thrusters.
ENPULSION has provided nano-electric propulsion systems for DiskSat missions, scheduled to be launched by late 2024.
6. The Future of Field-Emission Electric Propulsion (FEEP)
The next generation of electric propulsion is the Field-Emission Electric Propulsion, which employs liquid metals such as cesium and indium for high-precision thrust for those missions where precision is extremely required, like space telescopes and deep-space probes.
In 2018, the first FEEP thruster was deployed in orbit called the IFM Nano Thruster.
Engineers are miniaturizing FEEP modules to fit inside CubeSats, so that even smaller spacecraft can employ advanced propulsion techniques.
Electric propulsion technology is developing at a breakneck pace, surmounting barriers to make long-duration space missions possible. Future missions will enjoy the benefits of:
Increased mission durations with sustained, low-fuel propulsion.
Reduced wear and tear on spacecraft components.
More maneuverability and efficiency in space exploration.