Anatomy of OpenStar: Wellington's fusion reactor

Fusion is the reaction that powers the sun. Nuclei fuse together and energy is released. Harnessing this clean and unlimited energy source could be a silver bullet in solving the climate crisis. Wellington-based startup OpenStar is getting close, and after a $35 million loan from the New Zealand Government's Regional Infrastructure Fund, the country is backing them. 

Ratu Mataira, the CEO and founder of OpenStar, grew up in Tawa. It’s a short drive from the Ngauranga Gorge warehouse where he and his team are now working on groundbreaking science technology. 

There is an electrifying energy at OpenStar, a sense of the cutting-edge and real-life science fiction unfolding. Ratu is ambitious and driven. He thinks New Zealand is strengthening as a science and engineering hub. “You can look at successive generations, starting off with [Ernest] Rutherford. To do globally relevant work you couldn’t even come back to New Zealand, your whole career was built overseas.” That’s all changed now. Ratu believes that for certain disciplines, “New Zealand is actually the best place to do it.” 

Wellington, in particular, has something the rest of the world doesn’t — and it’s not the wind. “[There is] a really strong concentration of magnet engineering talent. People building these super-powerful, super-conducting magnets. That’s the Robinson Research Institute. It’s also a halo effect. There’s a centre of gravity around here and that’s fantastic for recruiting and building out a team.” 

OpenStar caught the world’s attention in 2024 when they successfully created plasma and contained it using a magnetic field inside their reactor. Plasma is the same state of matter as the sun. The plasma OpenStar created reached upwards of three-hundred-thousand degrees Celsius. “It’s safe,” Ratu assures with a grin as he walks beneath the reactor. 

There is a healthy dose of Kiwi ingenuity at OpenStar that has let them achieve the same results as other, much larger and better-funded ventures. When they started in 2021, it was from Ratu’s flat in Mt Victoria. “I don’t know if a can-do attitude is the right way to phrase it,” says Ratu. “But it’s a ‘why not?’ We’ve still got a bit of explorer blood left in us.” 

Outside the wall that surrounds the OpenStar reactor hangs a collection of bright orange hardhats, each with a distinct label. Aragorn, Gimli and the rest of ‘The Lord of the Rings’ characters. “We’re proud of being from Wellington,” says Alaina Pitt, the communications lead at OpenStar. 

OpenStar is also working on a project that would provide them with a revenue stream and allow them to pursue viable fusion energy without being so reliant on fundraising. “Once you have a machine that can run a fusion reaction, you’re getting neutrons. One of the things you can do with those neutrons is called nuclear chemistry. It’s changing isotopes of different elements to be useful medical isotopes for the healthcare system. It’s a really exciting market.” 

Ratu wears several hats as CEO, including that of a businessman, scientist, engineer, venture capitalist, and leader. He regards his work not only as a privilege but a responsibility: tackling the worsening climate crisis. “My generation’s responsibility was to take on this particular problem,” he says. “It focused what I was going to contribute on.” His excitement around the project is infectious. When viable fusion is achieved, it will be a generation’s most significant discovery. That possibility is intoxicating and thanks to OpenStar, Wellington has found itself at the centre of it.