An International Partnership Is Developing Nuclear Fusion Propulsion for Spacecraft

Back in 2022, researchers from the Lawrence Livermore National Laboratory in California unveiled a new method of potentially making nuclear fusion viable. Now, two companies have partnered to bring fusion technology to the realm of spacecraft propulsion, a development that could drastically shorten the time it takes to travel to distant worlds.

The fusion process is straightforward enough: simple atomic nuclei fuse into complex ones, just like we see in stars. But it has been difficult for decades to figure out a way to create a fusion process that generates more energy than what is put into it.

In the wake of Lawrence Livermore National Laboratory’s breakthrough, large-scale experiment, other companies are considering fusion for their future, including Oxfordshire-based Pulsar Fusion, which has now partnered with the United States’ Princeton Satellite Systems.

Pulsar emphasized it is trying to be “very careful” about what they say about the project, because viable fusion remains an idea on the horizon for now. But it is on their roadmap as they work to create nearer-term projects to diversify their funding and satisfy investors.

“We build electric propulsion systems, which is all plasma physics and electromagnetic confinement, fusion studies,” Pulsar founder and CEO Richard Dinan told SpaceRef, with applications including second-stage “kicker” engines to send satellites to orbit after a launch. “We speak to aerospace companies on daily basis, and we build what people want to buy, and we deliver them on time on budget, and they work.”

The new partnership pools the two companies’ resources, with Pulsar now receiving access to Princeton’s data on fusion studies conducted with a reactor known as the Princeton Field-Reversed Configuration.

The long-term goal of the project, which is still very experimental, is to create a direct fusion drive for spacecraft propulsion. Simply put, magnetic confinement and heating, alongside fuels of helium-3 and deuterium, are being tested to create the specific impulse and variable thrust needed for space missions.

“To be able to share this data, where we can now incorporate that live fusion reactor data into the design of our engine for us, internally — at least — it’s an incredible partnership,” Dinan said. Next steps could include building an engine to scale, and creating or using a big chamber to house electromagnetic fields for testing.

Dinan emphasized that the project is at an early stage and the challenge is finding a viable path to success in an environment that prioritizes raising money for near-term investments. That said, the hope is the company could use some form of machine learning to learn more about how plasma behaves, which he characterized as a “bit like a weather system” and “chaos itself.”

“It’s so complicated that every single reaction changes the state of that part, but we can’t actually study it [easily] as we don’t know what we don’t know,” Dinan said. He suggested that one approach could be to study plasma under electromagnetic confinement.

The two-year mission for the partnership is to break down the research into “achievable chunks and deliver them,” he said, but at this early stage, it is hard to predict where exactly the research would take them.

The vision, he added, would be to build a reactor at a large enough scale to allow for the right conditions for fusion to take place, such as suitable plasma temperature. That could include varying the sizes of reactors during the development process, as one way in which the research could vary.

Once fusion energy gets going to the point of being feasible and practical — which Dinan believes will happen, sooner or later — Dinan said that it will be a natural fit to improve space exploration.

In particular, the company suggests that a trip to Mars, currently a nine-month journey, could take just 30 days. A trip to Titan could become a two-year mission instead of taking seven.

The shorter transit times permitted by high-speed fusion propulsion not only would put distant planetary destinations within easy reach, but could also help buttress the quickly growing lunar economy or make missions to Mars more feasible, as some examples.

“I think we’re not there yet,” Dinan said of the technology, but he emphasized small steps are achievable. He declined specifics on what kinds of missions Pulsar would want to do, saying it really depends on larger priorities — including whether it ends up being humans or robots to make the journeys to these faraway zones.