For decades, scientists have tried to harness nuclear fusion—the process that powers stars—in reactors here on Earth. Currently, practical fusion is still a long way off, but there is enormous investment in this power source, because it could theoretically produce a virtually limitless supply of clean energy, perhaps exceeding global demand and enabling the transition to a decarbonized grid. Now, a researcher is pursuing a new twist on this longstanding goal: fusion reactors in space.
Picture massive doughnut-shaped reactors, known as tokamaks, floating in geostationary Earth orbit, or satellites blasting lasers across space to ignite fusion reactions. For now, these visions are speculative. But physicist Young K. Bae, PhD, believes that space-based fusion power could offer advantages over its terrestrial counterpart and may, one day, fuel the expansion of human civilization into space, according to his new paper published in the peer-reviewed journal Acta Astronautica.
"I’ve been working on this as an opening to a spacefaring civilization in the future," Bae says in an interview. "That’s my goal right now—a footstep that humanity can build on." While it’s not exactly a one-person job, Bae hopes to take a crack at it, he adds.
Bae is one of a small group of scientists interested in pioneering designs for fusion reactors in space. These structures could power off-Earth habitats, space manufacturing projects, orbital data centers, deep-space exploration, and all manner of other applications. His paper presents a rough roadmap toward a gigawatt-class tokamak—comparable to at least one large coal or nuclear plant capable of powering roughly one million homes—that might fulfill these lofty goals.
Space-based fusion power "enables higher power density for industrial-scale operations and deep-space missions where continuous power availability is critical" and "becomes increasingly advantageous at multi-gigawatt scales," Bae writes in the paper.
Nuclear fusion occurs when two or more atoms merge into a single atom, a reaction that releases a colossal amount of energy. When you bask in the sun in the daytime or gaze at distant stars at night, you are experiencing the awesome power of fusion reactions. For more than a century, scientists have grappled with the tall technological order of reconstructing this process in reactors.