A new kind of space engine could change how we explore the solar system, and it’s powered by the same force that lights up the stars. A British startup called Pulsar Fusion is working on a nuclear rocket that uses fusion energy to propel spacecraft at unprecedented speeds. If successful, the company says it could cut the travel time to Mars exponentially.
Named Sunbird, the concept is still in development, but Pulsar plans to test its technology in orbit as early as 2027. The idea is simple in theory: meet a spacecraft already in orbit, attach to it like a space tug, and blast off toward its destination using fusion-powered thrust.
Fusion is often considered the holy grail of clean energy. Unlike nuclear fission, which splits atoms and produces long-lived radioactive waste, fusion joins lightweight atoms like hydrogen into heavier ones, releasing far more energy — and without the radioactive byproducts. On Earth, the goal is to generate electricity. In space, Pulsar wants to skip that step and use the reaction directly for propulsion.
Sunbird’s nuclear rocket engine will use helium-3, a rare form of hydrogen, to fuel fusion reactions that produce energetic protons. These protons would shoot out of the back of the engine, creating forward thrust. Because Sunbird doesn’t need to convert the fusion reaction into electricity, the system can be inefficient but still incredibly useful.
One reason this may actually work is because space itself is an ideal environment for fusion. On Earth, engineers have to fight against gravity and atmospheric pressure to contain the ultra-hot plasma needed for fusion to occur. In the vacuum of space, those barriers don’t exist. As Pulsar’s CEO Richard Dinan says, space is where fusion wants to happen.
There are challenges ahead, of course, including miniaturizing the fusion hardware, managing heat, and designing a compact power system. But if Pulsar can prove the concept in orbit, the long-term possibilities are enormous. Sunbird could one day shuttle satellites, ferry cargo to the Moon, or even power a crewed mission to Mars in under six months.
