He’s 32, has 55 employees, and is building a nuclear fusion reactor in Wellington

Thursday, 5 June 2025

Ratu Mataira founded OpenStar three years ago, with the aim of being the first in the world to achieve the holy grail of energy generation: nuclear fusion. He’s making giant strides towards it, planning on having the first power station up and running in less than a decade. Explainer Editor Lloyd Burr visited OpenStar’s Wellington headquarters.

Being a nuclear-free country, I thought there’d be no chance of New Zealand being one of the world leaders in researching, developing, and achieving the elusive scientific holy grail that is nuclear fusion.

I was wrong.

It’s happening in Wellington by a start-up called OpenStar, and it’s happening fast.

According to the International Atomic Energy Agency, nuclear fusion “does not create any long-lived radioactive nuclear waste”.

One of the people pioneering it in New Zealand, is OpenStar founder and CEO is 32-year-old Ratu Mataira and he’s been obsessed with science since he was a kid.

“I wanted to be a scientist and was obsessed with how the world worked. It would eventually turn into physics with a brief foray into chemistry,” he says.

“My undergraduate is in physics and economics and my PhD is in superconductivity physics.”

My next question fell out of my mouth: Are you a genius?

“I won't answer that,” Mataira says with a grin.

But you have to be a genius if you want to solve one of science’s biggest mysteries, and to have convinced dozens of investors - including the taxpayer’s own venture capital fund - that you can do it.

What is nuclear fusion?

It’s often referred to as the holy grail of science because, if achieved, it can be used to produce enormous amounts of electricity without producing pollution.

Its fuel is also hydrogen - the most abundant element in the universe.

Fusion’s cousin is nuclear fission.

Fission is the method currently used in nuclear power plants around the world. In short, heavy atoms like uranium or plutonium are smashed apart, which creates lots of heat energy.

But the waste that’s left over has to be stored for decades.

It’s also resulted in disasters like Three Mile Island, Chernobyl, and Fukushima.

Nuclear fusion is the opposite of fission whereby lighter elements like hydrogen are forced to fuse - hence ‘fusion’ - to make a heavier particle like helium. This also creates a lot of heat energy which is then used to thermally generate electricity.

But in order to achieve that fusing, there needs to be tremendous heat. We’re talking hundreds of millions of degrees celsius - much hotter than the sun (which is a fusion reaction itself).

Getting to this stage and achieving stability to create a commercial energy source has proved impossible so far.

There are a number of methods being used to attempt fusion. Most use magnets like OpenStar but others use lasers, volts, and particle accelerators.

“Fusion is one that's often hailed as like the holy grail,” Mataira says.

“It's the hardest. The reason no one's done it yet is because it is so hard, but it has the most promise.”

Where’s OpenStar at?

In October last year, it “achieved plasma”, which is a significant milestone on the journey to fusion.

What does that mean?

Let me back up a bit.

They carry out their experiments in a big steel containment device, nicknamed Junior, that looks like a giant UFO.

It was made in Palmerston North, trucked to Wellington and craned into OpenStar’s shed.

Inside Junior, they put a device that looks like a steel inner tube of a truck tyre.

Inside this steel donut is a heap of complex technology. There are coils of superconducting steel and copper, batteries, circuit boards and wires.

Electromagnets are used to levitate the donut inside Junior, which, once all the hatches have closed, becomes a vacuum.

Hydrogen is added, along with some other complex things, and the donut’s magnetic field sends the differently charged atoms spinning around at tremendous speeds, becoming a hot gooey mess known as plasma.

What next?

The mission now is to refine the plasma stage so, instead of the atoms simply hugging and becoming a hot mess, they actually fuse together to become something else entirely.

They’ll need to get a lot hotter to do that which requires a more senior Junior - a new containment vessel that can handle the heat.

It’s essentially small steps, making plasmatic gains each time.

“The way I like to put it is there are four machines. We've just finished the first one, the last one is the power plant, and the two in between are us learning how to build the power plant,” Mataira says.

“They are good sequential steps. Instead of trying to jump straight to the fourth machine, we’re just trying to be a bit more practical about it”.

Once they achieve fusion, the big hurdle will be keeping the hydrogen fusing in a stable way.

That’s the holy grail.

“The science side of it is understood. But turning that into practical engineering where you're actually controlling the plasmas, kind of taming them to be part of an overall machine, that's the stage that we're at as an industry,” Mataira says.

Once they’ve tamed it, Mataira says the world as we know it will change.

“OpenStar successfully turning on Junior has shown the world that New Zealand can have a fusion company. If we manage to build the next machine here in New Zealand, we will officially have a fusion industry,” he says.

“That will be a significant enough project that will pull in other companies, there will be upskilling of the industry around us to make that a reality.

“And as a patriot, let's say I'm very keen for that to happen in New Zealand.”

Mataira’s time frame is mind-boggling.

He wants a fusion power plant up and running by the early 2030s.

Is it actually achievable? Let’s ask a nuclear physicist

“Yes,” University of Auckland’s Dr David Krofcheck says.

“But it’s really tricky.

“Can New Zealand do it? Why not? Will it be the 2030s? Maybe not, because fusion has traditionally been so hard to achieve.”

Dr Krofcheck applauds Mataira’s innovative gumption, especially chasing the lesser-known technique of using a levitating donut magnate.

“If we're going to do this in New Zealand, this is probably the nice way to go because it's kind of a little bit backwards from the rest of the world in the way they arrange magnetic fields and plasmas,” Dr Krofcheck says.

“I think it's a very clever idea that they have. I hope he's right, but it's really tricky.

“Fusion has always been a very clever way to produce energy without having nuclear waste products left over so I think, if anything, New Zealanders should probably appreciate this.”

Why is Mataira doing this?

His answer will go down in history if he manages to pull it off.

“There was a moment where I realised no one else was gonna do it, so it had to be us,” he says.

“Growing up for me, it became pretty apparent that climate change was the major issue of our time and if I could dedicate myself and my career to one goal, that was probably going to be it.

“It's not whether or not I think I can do it. It's more about the fact that we have to try, right? We just wake up every day and we ask ourselves: ‘What can we do to make progress and move this thing forward?’.

“It's pretty exciting”.

An earlier version of this story suggested fusion does not produce radioactive waste, that waste produced by fission needs to be stored forever and that stable fusion has been impossible so far. Amendments have been made to these sentences. (Amended 8.53am, 11/06/2025)