OpenStar

OpenStar Technologies is a Wellington-based New Zealand company focused on the development of nuclear fusion power systems. Founded in 2021 by physicist and chief executive Ratu Mataira, the company is pursuing a levitated-dipole reactor concept rather than the tokamak architecture used by many better-known fusion projects. Its stated long-term objective is to develop a sequence of experimental machines leading to a reactor capable of supplying electricity to the grid during the 2030s. The company emerged from Mataira’s research background at the Robinson Research Institute of Victoria University of Wellington, an institution known for work involving superconductors. Mataira became interested in levitated-dipole fusion after revisiting a concept that had received attention in the United States but lost government funding in 2011. OpenStar is described as the first New Zealand company to attempt development of a nuclear fusion reactor, giving it a distinctive position within the country’s technology and advanced-energy sectors. OpenStar’s initial machine, named Marsden after the English-New Zealand physicist Ernest Marsden, is designed around a cylindrical vacuum chamber with domed ends. Inside the chamber, a superconducting toroidal magnet, named Junior, is intended to levitate within the plasma environment. This arrangement differs from conventional magnetic-confinement systems in which the principal magnets are positioned outside the vacuum vessel. The company identifies the durability and operation of a magnet surrounded by extremely hot plasma as one of its central engineering challenges. In November 2024, OpenStar reported that it had produced plasma lasting approximately 20 seconds at a temperature of about 300,000 degrees Celsius. That achievement represented an experimental plasma milestone, but it was not yet fusion power generation: temperatures in the hundreds of millions of degrees are generally required for sustained fusion reactions. The company’s proposed fuel cycle involves the hydrogen isotopes deuterium and tritium. In addition to electricity generation, Mataira has discussed possible future applications in the production of isotopes used by the pharmaceutical industry, which are traditionally associated with fission-based facilities. OpenStar had raised a reported total of NZ$20 million by 2024. Mataira estimated that successful development of a fusion reactor would require approximately NZ$500 million to NZ$1 billion, illustrating the substantial capital requirements and technical uncertainty associated with commercial fusion. In February 2026, the New Zealand Government reportedly provided OpenStar with a NZ$35 million loan through the Regional Development Fund to support construction of a new research facility. By June 2025, the company was reported to have 55 employees. OpenStar remains a research and development venture rather than a commercial electricity supplier. Its brand is associated with ambitious climate and energy technology, New Zealand scientific entrepreneurship, and an attempt to develop a nontraditional fusion-reactor design. Commercial deployment, grid supply, fuel-cycle implementation, and any pharmaceutical-isotope business remain future objectives rather than established operating activities.

OpenStar Technologies was founded in Wellington in 2021 by Ratu Mataira, a physicist whose academic work included a PhD completed at the Robinson Research Institute of Victoria University of Wellington. The institute’s expertise in superconductors was relevant to Mataira’s interest in magnetic-confinement approaches to fusion energy. He became interested in the levitated-dipole concept after learning about earlier work on the approach in 2020. The concept had attracted attention in the United States but had been defunded by the US government in 2011. OpenStar was established to revisit that concept and develop a practical sequence of experimental devices. The company’s objective is not simply to demonstrate hot plasma, but to progress toward a fusion reactor that could eventually supply electricity to the grid. Because no fusion reactor has yet supplied electricity commercially at grid scale, the company operates in a field marked by substantial technical, financial, and engineering uncertainty. OpenStar’s formation was also notable within New Zealand: it has been described as the country’s first company to attempt development of a nuclear fusion reactor. The company’s principal design is a levitated-dipole reactor. Its first machine, Marsden, is named for Ernest Marsden, an English-New Zealand physicist. Marsden consists of a vacuum chamber approximately five metres in diameter, formed as a cylinder with domed ends. A superconducting toroidal magnet called Junior, approximately one metre in diameter, is intended to levitate inside the chamber. This configuration places the magnet within the plasma environment, unlike many tokamak designs whose magnets are arranged outside the vacuum vessel. Maintaining a superconducting, battery-powered magnet in a useful operating condition while it is surrounded by high-temperature plasma is one of OpenStar’s principal engineering problems. OpenStar reported a significant experimental step in November 2024, when it created plasma that lasted approximately 20 seconds at about 300,000 degrees Celsius. The result demonstrated progress in plasma production and confinement, but remained far below the temperatures normally associated with fusion conditions, which are measured in the hundreds of millions of degrees Celsius. The company’s proposed reactors are expected to use deuterium and tritium, two isotopes of hydrogen used in many fusion concepts. Funding has been a central part of the company’s development. OpenStar had reportedly raised NZ$20 million in total by 2024. Ratu Mataira estimated that between NZ$500 million and NZ$1 billion could ultimately be needed to develop a functioning fusion reactor. He has also identified a possible secondary application in the production of medical isotopes for the pharmaceutical industry, potentially creating a route to commercial value before grid-scale fusion electricity becomes possible. In February 2026, the New Zealand Government reportedly lent OpenStar NZ$35 million through the Regional Development Fund. The company said the funding would support construction of a new research facility. By June 2025, OpenStar had 55 employees. The company remains an active research and development enterprise, with commercial electricity production and any isotope business still prospective rather than operational.

• 2026

  Government research-facility loan

  [1]OpenStaren.wikipedia.org

  The New Zealand Government reportedly lent OpenStar NZ$35 million through the Regional Development Fund to help build a new research facility.

• 2025

  Workforce reaches 55 employees

  [1]OpenStaren.wikipedia.org

  OpenStar was reported to have 55 employees as of June 2025.

• 2024

  Reported cumulative funding reaches NZ$20 million

  [1]OpenStaren.wikipedia.org

  OpenStar was reported to have raised NZ$20 million in total by 2024.

• 2024

  Plasma milestone achieved

  [1]OpenStaren.wikipedia.org

  The company reported creating plasma lasting approximately 20 seconds at about 300,000 degrees Celsius.

• 2021

  OpenStar is founded

  [1]OpenStaren.wikipedia.org

  Ratu Mataira founded OpenStar in New Zealand to develop a levitated-dipole nuclear fusion reactor.

• 2020

  Founder studies the levitated-dipole fusion concept

  [1]OpenStaren.wikipedia.org

  Ratu Mataira became interested in the levitated-dipole approach, which later formed the technical basis of OpenStar’s reactor program.

An ambitious New Zealand advanced-energy company pursuing a differentiated levitated-dipole approach to nuclear fusion and eventual grid-scale electricity generation.

• Experimental fusion machine

  Marsden

  Marsden is OpenStar’s first experimental fusion machine. It uses a roughly five-metre vacuum chamber with a cylindrical body and domed ends. The chamber is designed to accommodate a levitating superconducting toroidal magnet and the plasma environment needed for the company’s levitated-dipole research program. Marsden is named after Ernest Marsden, an English-New Zealand physicist.

• Superconducting fusion magnet

  Junior

  Junior is the name given to the first magnet intended for use inside the Marsden machine. It is a superconducting toroidal magnet of approximately one metre in diameter that is designed to levitate within the vacuum chamber. Its operation in an environment surrounded by very hot plasma is central to OpenStar’s engineering approach and presents a major technical challenge.

• 2026

  Expansion of research infrastructureStrategy

  Background

  Further reactor development requires larger and more capable research facilities.

  Action taken

  OpenStar said it would use a NZ$35 million New Zealand Government loan from the Regional Development Fund to build a new research facility.

  Aftermath

  The funding was intended to expand the company’s research capacity, although commercial fusion generation remained a future objective.

  Government loan. NZ$35 million (February 2026)

  Source

• 2024

  Progression from device construction to plasma experimentationGeneration change

  Background

  OpenStar’s development program required experimental validation before the company could pursue fusion conditions or a grid-capable system.

  Action taken

  The company operated its experimental apparatus and reported plasma lasting approximately 20 seconds at about 300,000 degrees Celsius.

  Aftermath

  The result provided evidence of progress in plasma production, while remaining substantially below the temperatures required for fusion and commercial electricity generation.

  Source

• 2021

  Adoption of the levitated-dipole reactor strategyStrategy

  Background

  OpenStar was established around the levitated-dipole concept after Ratu Mataira studied the approach and its earlier development history.

  Action taken

  The company chose to develop a reactor in which a superconducting toroidal magnet levitates inside the vacuum chamber, distinguishing its design from externally magnetized tokamak systems.

  Aftermath

  This decision defined OpenStar’s technical identity and led to the Marsden and Junior experimental system.

  Source

1. 1OpenStaren.wikipedia.org