A British start-up has unveiled an ambitious project that could transform space exploration. Their idea? Using nuclear fusion to power a fleet of reusable rockets, nicknamed Sunbirds, capable of significantly reducing travel times within the Solar System.
Sunbirds could be stored in orbit.
Credit: Pulsar Fusion
These rockets, developed by Pulsar Fusion, would use an innovative nuclear fusion engine, the Direct Fusion Drive (DDFD). This system promises exhaust velocities far superior to current technologies, potentially halving travel time to Mars, for example. The first tests of this technology are planned for this year, with a goal of achieving orbit by 2027.
The Sunbirds concept relies on platforms where the rockets would be stored before deployment. They could act as "space tugs," attached to other spacecraft. This approach could reduce the costs of long-distance space missions.
Sunbirds could serve as space tugs, propelling spacecraft out of Earth's orbit.
Credit: Pulsar Fusion Unlike terrestrial fusion reactors, which aim to produce continuous energy, the DDFD engines would operate in short bursts. They would use a mixture of deuterium and helium-3, a rare isotope, to generate propulsive protons. This reaction, simpler to achieve in space, benefits from the natural vacuum and extremely low temperatures.
The Sunbirds could also serve as space batteries, powering the systems of the spacecraft they are attached to. Their robust design, with thick shielding, protects them from cosmic radiation and micrometeorites. Each rocket would cost around $90 million, but the savings on space missions would justify this investment.
Orbital docking stations could enable faster and more economical space travel.
Credit: Pulsar Fusion
The first tests of the DDFD engine will take place this year in giant vacuum chambers in England. Although actual fusion is not yet achievable, these tests will validate the concept. Pulsar also plans an orbital demonstration in 2027, but the timeline for a functional prototype remains uncertain.
How does nuclear fusion work in space?
Nuclear fusion involves merging light atomic nuclei to release colossal energy. On Earth, fission reactors, such as tokamaks, aim to fuse deuterium and tritium to produce continuous energy. In space, the DDFD engine uses a mixture of deuterium and helium-3, a rare isotope, to generate propulsive protons.
This reaction is simpler to achieve in space due to the natural vacuum and extremely low temperatures. Unlike terrestrial reactors, the DDFD operates in short bursts, reducing technical constraints. The protons produced are directly used for propulsion, offering exhaust velocities far superior to traditional chemical engines.
Concept video of Sunbirds in action.
Credit: Pulsar Fusion
Helium-3, although rare on Earth, could be extracted from the lunar surface in the future, making this technology more accessible. This approach paves the way for faster and more economical space travel, while reducing reliance on chemical fuels.
What are the advantages of Sunbirds?
These reusable rockets could halve travel time to Mars, making interplanetary missions more feasible. Their design as "space tugs" allows them to propel other spacecraft from Earth's orbit, avoiding the costs and risks associated with surface launches.
In addition to their propulsion role, Sunbirds could serve as space batteries, powering the systems of the spacecraft they are attached to. Their robust shielding protects them from cosmic radiation and micrometeorites, ensuring increased durability in the harsh space environment.