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Pulsar Fusion aims for a 2027 fusion-drive demo in space after a brief krypton plasma test
Pulsar Fusion plans a 2027 space demo of a fusion engine that has so far briefly held krypton plasma in place. Helicity Space's CEO says space travel will change within a decade, though the only engine test described so far made plasma and reported no fusion.
The Scientist · Science desk
What happened
- Pulsar Fusion, a UK startup, hopes to fly a demonstration mission for its fusion propulsion engine to space in 2027.
- In March, a Pulsar Sunbird engine at the company's Bletchley facility briefly turned krypton gas into plasma, a test billed as first plasma inside a fusion engine.
- Helicity Space CEO Stephane Lintner told Live Science that space travel will change within a decade if the current trajectory holds.
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Why it matters
- decision Pulsar's 2027 mission is the one dated checkpoint against the decade forecast, so anyone planning around fusion propulsion has a single near-term event to judge the timeline by.
- constraint The 10-newton figure is calculated from reaction counts, so mission designers still have no measured fusion thrust to size a spacecraft around.
- capability If a drive does hold its thrust for months, speeds of hundreds of miles per second would bring the Mars-in-weeks trips Live Science describes within engineering reach.
Pulsar's own account of the Bletchley run is about where the plasma goes. The demonstration showed "the plasma will sit in the system where you want it to sit," Richard Dinan, the company's CEO and founder, told Live Science, describing plasma held by an electromagnetic field [6]. The company presented it as a demonstration of how it might confine plasma within its exhaust system [5]. Live Science's description of the run mentions plasma and confinement. It does not mention fusion reactions [5].
Thrust is where fusion has to show up. According to Live Science, a quintillion fusion reactions every second would give about 10 newtons, roughly the weight of a 1-liter bottle of water in the hand [10]. The argument for the engine is duration. That push would last months, against minutes for a chemical rocket [10], and over that time could carry a spacecraft to hundreds or even thousands of miles per second [11]. The thing the Bletchley test doesn't tell you is how many reactions per second a Sunbird engine can sustain, or for how long [5][10].
Duration is also the hard problem for fusion on the ground. Keeping superhot plasma confined at the right temperature is one of the main obstacles, the confinement record is 22 minutes, and no commercially viable reactor has been built [7]. A single month of continuous operation is 43,200 minutes, about 2,000 times that record [13]. The comparison is imperfect. Live Science argues that the same sustaining problems do not arise in a drive, because its plasma is fired out of the spacecraft to make thrust [8]. "Fusion propulsion in some ways is harder, and in some ways is easier, than terrestrial energy production," Bhuvana Srinivasan, a professor of aeronautics and astronautics at the University of Washington, told Live Science [9].
Size is the other constraint. The reactor has to fit inside a spacecraft that fits on a rocket, when machines like ITER are the size of houses. It also needs a heat source, fuel, propellant and magnets strong enough to keep the plasma from burning through the engine walls [12].
Lintner's decade forecast opens with a condition: "If we continue on the current trajectory" [3]. Of the three efforts the account names, only Pulsar has a date attached, the 2027 demonstration mission [1]. Helicity Space and Princeton are described as continuing their own work on fusion drives, with no milestones given [2]. I'd treat the decade as a projection that holds only while its first clause does. The 2027 flight is the first result that can check it, and only if it reports reaction rates and thrust along with plasma handling [1][10].
What to watch
- Whether Pulsar's 2027 demonstration mission flies on schedule, and whether it reports fusion reaction rates and thrust or only plasma handling.
- Whether Helicity Space or Princeton put dates or measured thrust figures on their fusion drive work.
- Any ground test that reports a sustained fusion reaction rate approaching the quintillion-per-second scale Live Science ties to 10 newtons.