Pulsar Fusion is a British aerospace start-up based in Bletchley, founded by the entrepreneur Richard Dinan.
Dinan, previously known for appearing on the reality television series Made in Chelsea, established the business in the early 2010s under the name Applied Fusion Systems before it was rebranded.
The company has spent more than a decade developing nuclear fusion technology, the process that powers the sun, with the aim of using it for both clean energy and spacecraft propulsion.
It employs a small team of engineers and scientists and has previously tested conventional hybrid rocket engines and electric thrusters.
What actually happened
Pulsar Fusion has achieved what it calls the world's first plasma ignition inside a nuclear fusion rocket exhaust system.
The test took place at the company's UK facility and was demonstrated live at a technology conference in California hosted by the Amazon founder, Jeff Bezos.
Engineers used powerful electric and magnetic fields to generate and confine a superheated, ionised gas known as plasma within the exhaust architecture.
For this particular test, the plasma was created using krypton gas, chosen because it becomes plasma efficiently at the required flow rates.
Meet Sunbird
The technology is part of a project called Sunbird, a reusable spacecraft designed to dock with other vehicles while in orbit.
Once docked, Sunbird is intended to provide continuous, high-thrust propulsion to carry spacecraft across the solar system.
For its eventual operational engine, known as the Dual Direct Fusion Drive, the company intends to run on a fuel mix of deuterium and helium-3, needed only in small quantities compared with conventional rocket fuel.
Why it matters
Chemical rockets, the kind used on most missions today, can take the best part of a year to reach Mars.
Pulsar Fusion says its fusion-based approach could eventually reduce that journey substantially, though reported estimates for the exact transit time vary between different accounts of the technology.
The Dual Direct Fusion Drive is designed to generate two megawatts of power alongside continuous thrust, potentially offering roughly a thousand times the thrust of existing in-orbit propulsion systems.
What comes next
Achieving plasma ignition validates the core physics behind the engine, but building a fully operational fusion-powered spacecraft remains a far larger engineering challenge.
Pulsar Fusion plans an in-orbit demonstration of Sunbird's core components in 2027, with a production-ready system not expected until the early 2030s.
Constructing the orbital docking stations Sunbird would need to refuel and operate in space is likely to prove just as demanding as the propulsion technology itself.
