How could MHD generators provide power for spacecraft and deep-space probes?

Magnetohydrodynamic (MHD) generators offer a potential method for providing electrical power to spacecraft and deep-space probes by converting the kinetic energy of a high-temperature, electrically conductive fluid directly into electricity as it moves through a magnetic field.123

For space applications, these systems have been investigated for both burst and continuous operations. The primary considerations for their use include:1

• Heat Sources: While both chemical and nuclear heat sources have been studied, nuclear heat is the preferred choice for supplying power to deep-space probes.1
• Operational Mechanism: Because conventional nuclear reactors operate at temperatures too low for the thermal ionization required by standard MHD generators, these systems would likely require nonequilibrium ionization techniques using seeding materials.1
• Advantages: MHD systems are attractive for space missions because they are direct energy-conversion devices, which can offer high reliability due to their lack of moving parts.3

While the potential for space-based MHD power has been considered, historical challenges—including the difficulty of finding viable applications for space missions—previously led to the curtailment of research in this area.4