Researchers at the University of Illinois Urbana-Champaign have made great progress in improving spacecraft efficiency for lunar missions using a new method called multimode propulsion. This innovative approach combines both chemical high-thrust and electric low-thrust propulsion while using the same fuel.
The goal is to optimize how spacecraft operate during missions to the Moon. Supported by NASA, the team analyzed four real mission scenarios to show how this technology can be applied.
Aerospace engineering Ph.D. student Bryan Cline highlighted the project’s significance: “This is the first detailed analysis of multimode mission design for lunar missions relevant to NASA, especially using CubeSats.” By working with a standard 12-unit CubeSat, the team could effectively explore different mission profiles.
One major advantage of multimode propulsion is its ability to lower the spacecraft’s dry mass significantly. Cline explained that using just one fuel tank simplifies the mass and volume, making it more efficient than traditional hybrid systems that need multiple fuels. “With multimode systems, the ability to switch between high-thrust and low-thrust modes improves maneuverability and reduces fuel use,” he said.
Cline’s team initially determined when to use high-thrust or low-thrust during mission simulations, which led to less efficient flight paths. To improve this process, he created an algorithm that automatically finds the best times to switch thrust modes, ensuring the most efficient route.
“We developed the first indirect optimal control technique for multimode mission design, helping us achieve goals like minimizing fuel use and transfer time,” Cline noted.
The researchers successfully tested this method for both two-dimensional transfers between Earth and Mars and three-dimensional transfers to geostationary orbit. Cline emphasized the method’s versatility: “This approach can adapt to many mission design challenges, ensuring the best solutions through variational calculus.”
Cline pointed out the potential of multimode propulsion as a new technology that can improve mission capabilities. “This advancement offers more flexibility and adaptability, allowing for missions that were previously impossible,” he said. “We are at an exciting point for multimode propulsion, translating our lab research into practical uses that will benefit the wider space community.”
