David Kirtley

He has pursued advanced fusion systems since the late 1990s, holds graduate degrees in nuclear, plasma and aerospace engineering from the University of MichiganUniversity of MichiganThe University of Michigan is a university founded in Detroit in 1817 that moved to Ann Arbor, Michigan, in 1837; it is governed by a statewide-elected Board of Regents and also has campuses in Dearborn and Flint.Open the full entry, and has been a fellow of the National Science Foundation, NASANASAThe National Aeronautics and Space Administration (NASA) is the U.S. federal agency responsible for the civilian space program, aeronautics research and space science. Established by law in 1958 and headquartered in Washington, D.C., it has run programs including Mercury, the Apollo Moon landings, the Space Shuttle, the International Space Station and Artemis.Open the full entry and the Department of Defense; his expertise covers advanced-fuel fusion generators, plasma-based in-space propulsion and space reentry architectures.⁠[1]

He holds a Ph.D. in aerospace engineering from the University of Michigan.⁠[2]

On November 2, 2009, as a researcher at MSNW LLC, he co-authored with Thomas Weber, Brian Nelson and Richard Milroy of the University of Washington’s Plasma Dynamics Laboratory and John Slough a presentation on the “Electrodeless Lorentz Force Thruster” at the annual meeting of the APS Division of Plasma Physics; the thruster uses rotating magnetic field current drive to form a field-reversed configuration plasmoid and eject it at high velocity.⁠[3]

He recalls that before spinning off Helion to focus only on fusion, the founding team worked on a mix of advanced materials, rocket propulsion, fusion rockets and fusion materials.⁠[4]

In 2013 he founded Helion in Washington State with Chris Pihl, John Slough and George Votroubek, aiming to build a fusion system designed for commercial electricity; he serves as co-founder and CEO.⁠[5]

In August 2014 Y Combinator and Mithril Capital Management invested $1.5 million in Redmond-based Helion, which had been founded by four scientists working at MSNW, a University of Washington spin-off; he said then that the company could reach break-even within three years for just a few tens of millions of dollars.⁠[6]

Helion was part of Y Combinator’s Summer 2014 batch, listing him as founder/CEO and Chris Pihl as founder/CTO.⁠[7]

In September 2020 Helion closed a $40 million Series D led by Dustin Moskovitz at a $1.25 billion valuation, bringing its funding since 2013 to $77.8 million; he said the climate crisis and growing energy demand required a dramatic acceleration of zero-carbon baseload technologies.⁠[8]

In June 2021 Helion announced that its sixth prototype, Trenta, had exceeded a fuel temperature of 100 million degrees Celsius—the first private company to announce this—and had completed a 16-month test campaign; he called the results breakthroughs for how the world meets its electricity needs.⁠[9]

He recalls that in its Redmond years the team used StarbucksStarbucksStarbucks is a publicly traded coffee company headquartered in Seattle, founded in 1971 by Jerry Baldwin, Gordon Bowker and Zev Siegl. Howard Schultz subsequently developed its coffeehouse model and international expansion. It operates company-owned and licensed coffeehouses and sells packaged coffee through partners. Its shares trade on Nasdaq under SBUX.Open the full entry cups on the machines for scale, so prototypes were named Tall, Grande and Venti after cup sizes, with the largest, Trenta, coming online in 2020.⁠[4]

On July 27, 2021 Helion broke ground on its next-generation fusion facility in Everett, Washington, attended by Governor Jay Inslee and Mayor Cassie Franklin; he said the company had spent more than eight years developing its technology in the state and that the facility would help it break the fusion barrier.⁠[10]

On November 5, 2021 Helion announced a $500 million Series E led by Sam AltmanSam AltmanSam Altman is an entrepreneur and investor, and the co-founder and chief executive officer of OpenAI. He previously served as president of Y Combinator and founded the location-based social service Loopt. He also helped found Tools for Humanity and Merge Labs, has invested in energy and life sciences ventures, and has driven public discussion of AI governance, employment, and wealth distribution.Open the full entry, with an option for a further $1.7 billion tied to milestones, to complete Polaris, its seventh-generation fusion generator; Altman had been an investor and chairman since 2015. He said the funding ensured Helion would be first to generate electricity from fusion.⁠[11]

In May 2022 Helion moved its headquarters from Redmond to a 150,000-square-foot building in Everett, with 80 employees at the time, and received Economic Alliance Snohomish County’s Opportunity Lives Here Award; he said the move was for the local workforce and that the company would need to hire well over 1,000 people once manufacturing plans advanced.⁠[12]

In August 2022 Senators Carper and Capito wrote to the Nuclear Regulatory Commission urging fusion regulation distinct from fission; speaking for Helion, he said clear, differentiated rules would help fusion deploy safely and rapidly, and thanked the two senators.⁠[13]

On May 10, 2023 Helion announced an agreement to supply Microsoft with electricity from its first fusion power plant, with Constellation as power marketer; the plant was expected online by 2028, targeting 50 MW or more after a one-year ramp-up. He called it a significant milestone for Helion and the fusion industry.⁠[14]

He said it was a real PPA with financial penalties if Helion could not deliver power; Andrew Holland, CEO of the Fusion Industry Association, called the 2028 goal “aggressive”.⁠[15]

On September 27, 2023 Helion and Nucor, North America’s largest steel producer, announced an agreement to develop a 500 MWe fusion plant at a Nucor steel facility in the United States, including an investment by Nucor in Helion; he said the company was committed to reducing the world’s dependence on carbon-based energy with fusion.⁠[16]

In 2023 he and Sam Altman met OpenAIOpenAIOpenAI is an artificial intelligence research and product organization founded in 2015 that develops the GPT model series, ChatGPT, Codex and a developer API, and conducts research on image, speech, video and intelligent agents. After its 2025 restructuring, the nonprofit OpenAI Foundation continues to control the for-profit OpenAI Group PBC. Its growth has involved large-scale fundraising and compute partnerships, and has also been accompanied by controversies over governance, copyright, privacy and AI safety.Open the full entry Forum members at OpenAI’s office to discuss the future of energy; the recording was posted on November 29 that year.⁠[17]

On July 25, 2024 the Special Competitive Studies Project named him a commissioner of the Commission on the Scaling of Fusion Energy, co-chaired by Senators Maria Cantwell and Jim Risch and Ylli Bajraktari, which aims to put the United States at the forefront of the fusion race.⁠[18]

On July 30, 2024 Helion obtained a Large Broad Scope license from the Washington State Department of Health to possess and use byproduct material for operating Polaris; he said its emphasis on safety was first about the well-being of its team and community.⁠[19]

On January 28, 2025, Helion announced a $425 million Series F round, bringing its total funding to more than $1 billion.⁠[20]

In July 2025 Helion began work on the site of Orion, its first fusion power plant, on land leased from the Chelan County PUD in Malaga, Chelan County, Washington; he called it an important day for Helion and the whole fusion industry.⁠[21]

On October 15, 2025 Helion received a Conditional Use Permit from Chelan County clearing the way for permitting and building Orion’s fusion generator building, saying it remained on track to supply Microsoft by the end of 2028; he said the company was excited to move into this next phase.⁠[22]

He appeared on episode 485 of the Lex FridmanLex FridmanLex Fridman is a Soviet-born, US-raised computer scientist and podcast host who works as an MIT research scientist on human-AI interaction and autonomous driving. His Lex Fridman Podcast is known for hours-long conversations with guests including heads of state and technology leaders.Open the full entry Podcast, described on the episode page as a nuclear fusion engineer and CEO of Helion; topics included fission versus fusion, fusion safety, how fusion works, electricity from fusion, the first fusion power plant in 2028, the energy needs of GPU clusters and the Kardashev scale.⁠[23]

On February 13, 2026 Helion announced that Polaris, its seventh-generation prototype operating since the end of 2024, had become the first privately developed fusion machine to demonstrate measurable deuterium-tritium fusion and had reached plasma temperatures of 150 million degrees Celsius; he said the surest path to commercial fusion was to build, learn and iterate as quickly as possible.⁠[24]

Asked whether Helion had reached scientific breakeven, he did not answer directly, saying the company focused on making electricity rather than pure scientific milestones; he added that 200 million degrees was the optimal operating point for a power plant and that Polaris was a step toward scaled power plants.⁠[25]

On March 23, 2026 Sam Altman said he had stepped down from Helion’s board as OpenAI and Helion began to explore working together at significant scale, adding that he would recuse himself from deal negotiations. In an X post, he said Altman had played an integral role in Helion’s development and that he looked forward to working with him in a new capacity. A Helion spokesperson said the company had made no customer announcements beyond the Microsoft and Nucor deals.⁠[26]

On June 4, 2026 Helion announced a $465 million Series G led by Thrive Capital at a $15.5 billion post-money valuation, bringing total investment to $1.5 billion; the round closed oversubscribed at $500 million in September 2026. He said fusion was no longer a future idea but a path to clean, reliable, always-on electricity.⁠[27]

On October 22, 2026 Helion signed a letter of intent with the U.S. Department of Commerce to receive up to $175 million through the CHIPS Research and Development Office for next-generation high-voltage semiconductors for fusion, matched by $50 million in private investment; he said it would let Helion develop and manufacture the advanced semiconductors its systems need in the United States.⁠[28]

LinkedInLinkedInLinkedIn is a social networking platform for professionals. It was founded in 2002 by Reid Hoffman and others, launched in 2003, and listed on the New York Stock Exchange in 2011; after Microsoft acquired it for approximately $26.2 billion in 2016, it became a wholly owned Microsoft subsidiary. Its revenue comes from membership subscriptions, advertising, and recruitment solutions.Open the full entry: Public profile: https://www.linkedin.com/in/david-kirtley-490b8230/ (opens in a new window)⁠[23]

Helion Energy: Official website: https://www.helionenergy.com/ (opens in a new window)⁠[23]

Commission on the Scaling of Fusion Energy: Official website: https://fusion.scsp.ai/ (opens in a new window)⁠[2]