In the United Kingdom, a new type of fusion propulsion system for spacecraft is being developed. If the project, which is funded by the British Space Agency, is successful, it could reach Mars significantly faster than before. Pulsar Fusion, a company based in Bletchley, UK, is developing an advanced nuclear fusion rocket designed to significantly cut the travel time to Mars. Named the Sunbird engine, this innovative technology harnesses the same fundamental process that powers stars—nuclear fusion. What sets it apart from earlier efforts is that the fusion reaction will occur directly in space, offering a groundbreaking approach to deep space propulsion and potentially revolutionizing interplanetary travel.
The developers at Pulsar Fusion view space as the ideal setting for nuclear fusion. “Fusion should happen in space, not on Earth,” says CEO Richard Dinan in an interview with CNN. He explains that Earth’s environment requires highly complex and artificial conditions to achieve fusion, whereas space naturally provides the extreme conditions needed. Nuclear fusion involves combining light atomic nuclei—usually hydrogen isotopes like deuterium and tritium—to form heavier elements such as helium, releasing vast amounts of energy in the process. This is the same energy-producing reaction that powers the sun. Unlike nuclear fission, fusion generates minimal long-lived radioactive waste and carries a much lower risk of catastrophic accidents, making it a cleaner and safer option for the future of space travel.
Fusion reactor research has made significant progress in recent years. For example, the Chinese experimental reactor EAST was able to maintain stable plasma for almost 18 minutes in January 2025. However, this new world record only lasted a short time, as the French tokamak WEST surpassed this mark in February with over 22 minutes of stable plasma ignition. Furthermore, the commercial use of nuclear fusion faces major challenges, particularly with regard to the stability of the reactions and the economic viability of the technology. A saying has been circulating among physicists for decades: “Nuclear fusion is 20 years in the future—and always will be.”
Pulsar Fusion’s ambitious plans are not only groundbreaking but seem almost extraterrestrial, according to a report by Live Science. The company’s Sunbird rocket, designed with a futuristic armored structure and stretching approximately 30 meters in length, will be powered by helium-3—an exceptionally rare isotope scarcely found on Earth. Unlike traditional fusion fuels, helium-3 is not a byproduct but a component of the fuel mixture itself. When fused with deuterium, it primarily releases protons, creating a form of “nuclear exhaust radiation” that is expected to drive the rocket’s propulsion. This method promises to be cleaner and more efficient than standard fusion reactions, which typically emit high-energy neutrons. Looking ahead, Pulsar Fusion envisions harvesting helium-3 from lunar regolith to support sustained missions. The company’s immediate objective is to conduct a linear fusion trial to test the core technologies. If successful, a working prototype could be ready within four to five years—an ambitious target given the theoretical challenges and immense costs involved.
