A Magnetohydrodynamic Drive Could Lead to Fuel Stations on Mars
Within the next fifteen years, NASA, China, and SpaceX plan to send the first crewed missions to Mars. In all three cases, these missions are meant to culminate in the creation of surface habitats that will allow for many returns and – quite possibly – permanent human settlements. This presents numerous challenges, one of the greatest of which is the need for plenty of breathable air and propellant. Both can be manufactured through electrolysis, where electromagnetic fields are applied to water (H2O) to create oxygen gas (O2) and liquid hydrogen (LH2).
While Mars has ample deposits of water ice on its surface that make this feasible, existing technological solutions fall short of the reliability and efficiency levels required for space exploration. Fortunately, a team of researchers from Georgia Tech has proposed a “Magnetohydrodynamic Drive for Hydrogen and Oxygen Production in Mars Transfer” that combines multiple functionalities into a system with no moving parts. This system could revolutionize spacecraft propulsion and was selected by NASA’s Innovative Advanced Concepts (NIAC) program for Phase I development.
Recommendation comes from Assistant Professor Alvaro Romero-Calvo at the Georgia Institute of Technology and his colleagues at the Georgia Tech Research Corporation (GTRC). The system utilizes a magnetohydrodynamic (MHD) electrolytic cell based on electromagnetic fields to accelerate electrically conductive fluid (in this case, water) without any moving parts. This allows the system to extract and separate oxygen and hydrogen gas in microgravity, eliminating the need for mandatory water circulation and related equipment (such as pumps or centrifuges).
Romero-Calvo and his team, experts in low-gravity science, fluid mechanics, and magnetohydrodynamics, have spent years researching applications of MHD systems for space flights. The need for a specialized study to evaluate the feasibility of the concept and its integration into a suitable oxygen production architecture ultimately motivated their proposal. In a previous study, Romero-Calvo and co-author Dr. Katharina Brinkert, a Chemistry professor at the University of Warwick, had indicated how locally harvested water could reduce payload masses for spacecraft launches.
However, they also pointed out that operating such machines in microgravity presents many unknowns not addressed by most current research. Specifically, they highlighted significant technical challenges such as the need to separate and collect oxygen and hydrogen bubbles due to the absence of buoyancy in microgravity, which traditionally has been addressed using forced water circulation loops. However, they argued that this led to liquid management devices in space composed of multiple elements and moving parts, which were complex, inefficient, and unreliable. As Romero-Calvo mentioned in a recent Georgia Tech news bulletin:
“The idea of using MHD forces for liquid pumping was addressed in the 1990 thriller film The Hunt for Red October; in the film, a Soviet submarine using an MHD drive seeks asylum in the United States. While seeing Sean Connery as a Soviet submarine commander is entertaining, the reality is that submarine MHD propulsion is highly inefficient. In contrast, our concept operates in microgravity environments where weak MHD forces dominate, opening up capabilities that make the mission possible.”
Instead of traditional circulation loops, the proposed MHD system relies on two different mechanisms to separate oxygen and hydrogen from water. The first arises from diamagnetic forces induced in the presence of strong magnetic fields, leading to magnetic levitation effects. The second involves Lorentz forces resulting from the application of a magnetic field to a current between two electrodes. As stated in Romero-Calvo’s proposal article:
“Both approaches could potentially lead to next-generation electrolytic cells with minimal or no moving parts, thus enabling human deep space operations with minimal mass and power penalties. Initial estimates indicate up to 50% reductions in mass budgets compared to Oxygen Generation Assembly architectures for functions integrated to a 99% reliability level. These values apply to a standard four-crew Mars transfer consuming 3.36 kg of oxygen per day.”
If successful, this MHD system would enable the recycling of water and oxygen gas for long-duration space journeys. Romero-Calvo and his colleagues at the Daniel Guggenheim School of Aerospace Engineering at Georgia Tech have also demonstrated potential applications of this technology for other mission profiles where water-based SmallSat propulsion and ISRU are imperative. Currently, Romero-Calvo and his colleagues have formulated the concept and developed analytical and numerical models.
In the next step, the team and their partners at Giner Labs, a Massachusetts-based electrochemical R&D firm, will conduct feasibility studies. Over the next nine months, they will receive $175,000 to investigate the general applicability of the system and the readiness level of the technology. These studies will primarily involve computational work but will also include prototypes testing fundamental technologies on Earth. As a Phase I proposal, they will also compete for $600,000 in Phase II funding for a two-year study.
An early demonstrator of this technology was tested on December 19, 2023, during the 24th flight of Blue Origin’s New Shepard (NS-24), an unmanned mission. Supported by Blue Origin and the American Society for Gravitational and Space Research (ASGSR), Romero-Calvo’s team tested how magnets electrolyze water under microgravity conditions. Data from this flight and upcoming tests will inform a prototype of an HMD electrolyzer and could lead to an integrated system for future space missions. Romero-Calvo stated:
“We were investigating fundamental magnetohydrodynamic flow regimes when applying magnetic fields to water electrolyzers under space flight conditions,” Romero-Calvo said. “The Blue Origin experiment, along with our ongoing collaboration with Professor Katharina Brinkert’s group at the University of Warwick, will help us predict the movement of oxygen bubbles in microgravity and provide clues on how to build a water electrolyzer for humans in the future.”
Source: A Magnetohydrodynamic Drive Could Lead to Fuel Stations on Mars
A Magnetohydrodynamic Drive Could Lead to Fuel Stations on Mars