Pulsar Fusion: Leading the Next Generation of Krypton Plasma Space Propulsion

Pulsar Fusion
Bletchley, United Kingdom
www.pulsarfusion.com

Sunbird first plasma with krypton. (Image: Pulsar Fusion)

Today’s spacecraft rely primarily on two very different propulsion systems, each with fundamental limitations. Chemical rockets generate extremely high thrust, essential for launch and rapid maneuvers, but their relatively low exhaust velocities limit how fast spacecraft can ultimately travel through space.

Electric propulsion systems, such as ion or Hall thrusters, achieve very high exhaust velocities, making them highly efficient. However, they produce very low thrust, requiring spacecraft to accelerate gradually over long periods. Fusion propulsion has the potential to deliver both high thrust and extremely high exhaust velocities. This combination could dramatically shorten travel times across the solar system.

Pulsar Fusion, a U.K.-based space propulsion company developing advanced propulsion technologies for the rapidly growing satellite and deep-space markets, recently announced that it has achieved “first plasma” in its Sunbird exhaust test system. This milestone represents the first glimpse of the physical architecture of a nuclear fusion exhaust system for space travel.

Sunbird front view in chamber. (Image: Pulsar Fusion)

This achievement was demonstrated live during a dedicated technical session at Amazon’s MARS Conference in Ojai, California, where visionary leaders in machine learning, automation, robotics, and space gathered to shape humanity’s future beyond Earth.

The Sunbird demo was presented live by Pulsar Fusion CEO Richard Dinan to an esteemed group of world-leading machine learning and robotics academics/entrepreneurs, Nobel laureates, and astronauts. The test was performed by Pulsar Scientists in Bletchley, United Kingdom, and live streamed to the stage in California during Richard Dinan’s presentation.

This test marks an early step in development, demonstrating plasma confinement within the exhaust architecture of the Sunbird system. The experiment uses a combination of electric and magnetic fields to guide and accelerate charged particles through the exhaust channel.

Sunbird is powered by Pulsar Fusion’s state-of-the-art Dual Direct Fusion Drive (DDFD). With its high specific impulse (10,000–15,000 s) and 2 MW of power, the Sunbird redefines what’s possible in space travel. Dual Direct Fusion Drive (DDFD) is a compact design nuclear fusion engine which could provide both thrust and electrical power for spaceships. This technology opens unprecedented possibilities to explore the solar system in a limited amount of time and with a very high payload to propellant masses ratio. Since DDFD provides power as well as propulsion in one integrated device, it would also provide as much as 2 MW of power to the payloads upon arrival.

Sunbird in large vacuum test chamber. (Image: Pulsar Fusion)

The next phase of development will see Pulsar gather detailed performance data, including thrust and exhaust velocity, using a thrust balance, E×B probes, and RPA measurements. This data will enable Pulsar to plan the first Sunbird mission.

To maximize the mission lifetime of Sunbird, Pulsar has developed a research program in collaboration with the U.K. Atomic Energy Authority. The program will study the effects of neutron radiation on the reactor walls and magnets, a primary cause of wear within the reactor.

For this initial test series, krypton was used as the propellant, selected for its relatively high ionization efficiency and inert characteristics at the mass flow rates required for early testing.

Upcoming experiments will incorporate rotating magnetic field heating, RF heating systems, and a dedicated thrust balance to enable more detailed performance measurements.

Looking ahead, Pulsar Fusion plans to upgrade the magnetic system to rare-earth, high-temperature superconducting magnets, enabling stronger magnetic fields and the exploration of higher plasma density and pressure conditions. This program ultimately aims to begin experimental work with aneutronic fusion fuel cycles as part of the continued development of the Sunbird propulsion system.

This article was contributed by Pulsar Space (Bletchley, United Kingdom). For more information, visit here  .