The Pulsar Fusion company, based in the United Kingdom, has revealed a nuclear rocket design, called Sunbird. It offers the possibility of reducing a trip to Mars to under four months and Pluto to under four years.
Its concept involves small, modular units docking with a spacecraft and employing nuclear fusion engines to achieve significantly higher speeds and longer burn times, enabling faster transit to destinations like Mars.
Unlike traditional tokamak reactors that aim to contain fusion reactions for energy generation, Sunbird leverages plasma leakage for thrust, turning a potential flaw into a key feature.
Tokamaks rely on Deuterium-Deuterium (D-D) or Deuterium-Tritium (D-T) reactions, subjecting hydrogen isotopes to extreme pressures and temperatures within a confined space. This continuous process requires massive infrastructure, including large magnetic coils, cooling systems, radiation shielding, and armored containment vessels.
Instead, Pulsar Fusion’s Sunbird employs the Dual Direct Fusion Drive (DDFD) principle. This involves a straight chamber with a pinched section, using pulsed magnetic fields to accelerate plasma into the chamber, where particle collisions induce fusion.
The approach was previously dismissed due to leakage issues, but the company repurposes this flaw as a feature by using the escaping particles as exhaust for propulsion.
Sunbird uses what is called aneutronic fusion that uses deuterium and helium-3 (D+3He) to produce helium-4, energy, and protons, significantly reducing neutron production and enabling plasma control for rocket propulsion.
The Sunbird engine is able to offer a significant leap in performance compared to existing propulsion systems.
Chemical rockets are capable of high thrust, but they suffer from low specific impulse, limiting their efficiency. On the other hand, electric propulsion systems, like ion thrusters, boast high specific impulse but provide minimal thrust.
In addition, nuclear fission rockets offer a compromise, but their thrust is still slow. Meanwhile, Sunbird aims to offer both high thrust and a high specific impulse of up to 15,000 seconds, which is much more than ion drives.
In addition to propulsion, Sunbird also offers the potential for significant power generation. The plasma exhaust can be passed through a magnetohydrodynamic coil to generate 2 MW of electricity, dwarfing the power output of the International Space Station’s solar arrays.
This self-contained nuclear rocket tug is currently undergoing large vacuum test chamber trials. The company plans to demonstrate the technology later this year and begin orbital tests in 2027.
