Helion

David Kirtley earned bachelor's, master's, and Ph.D. degrees in Aerospace Engineering from the University of Michigan. Before founding Helion, he conducted space propulsion and plasma research at the Seattle-area company MSNW after initially exploring fusion during his studies but pausing to focus on aerospace projects such as rocket development. He completed the Y Combinator S14 program and held fellowships from NASA and the National Science Foundation.

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Chris Pihl founded and served as President of Pulse Power Solutions, LLC, a company focused on pulsed power systems, and held the role of Project Manager and Pulsed Power Engineer at MSNW. He earned a degree in Innovation Management and brings more than two decades of industry experience in pulsed power technology, including earlier leadership at May Creek Power.

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John Slough spent decades advancing field-reversed configuration plasma research as a researcher and professor at the University of Washington. He co-founded MSNW LLC, where he serves as Research Director, and has authored numerous publications on fusion and plasma physics technologies.

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George Votroubek earned his M.S. and Ph.D. degrees from the University of Washington, where he pursued experimental research in fusion and plasma physics as part of the Department of Aeronautics and Astronautics. He previously served as Group Leader at MSNW LLC after roles at the University of Washington.

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Anthony Pancotti earned a Ph.D. in Aerospace Engineering from the University of Southern California. Prior to Helion, he conducted propulsion research for a decade at MSNW LLC, serving in roles including director of propulsion research focused on plasma thrusters and solar thermal energy storage systems.

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Lynn Miller spent over 14 years at Apple leading worldwide litigation, regulatory enforcement, and privacy groups. She later served as Deputy General Counsel at Tesla, overseeing litigation strategy, government inquiries, and privacy programs, following an earlier partnership at the law firm Pillsbury Winthrop.

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Pragav Jain holds an MBA from Stanford Graduate School of Business and a BBA in Finance and Accounting from the University of Michigan Ross School of Business. Prior to Helion, he built a two-decade career in strategic finance, corporate development, M&A, treasury, and investor relations at organizations including Waymo, Goldman Sachs, and Morgan Stanley.

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Savanna Thompson previously served as VP of People at 98point6 Inc., a Seattle-based telehealth company, where she focused on human resources and recruiting in a high-growth environment. She joined Helion more than three years ago and has extensive experience building people functions, culture, and operational systems for scaling technology companies.

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Orion is Helion's first commercial fusion power plant, under construction in Malaga, Chelan County, Washington, on land leased from the Chelan County Public Utility District. Designed as a 50-megawatt facility to deliver clean, baseload fusion electricity to the grid with direct energy recapture and no steam cycle, it represents the company's eighth-generation machine and the initial deployment of its pulsed magneto-inertial fusion technology at commercial scale. Site work and initial earthwork began in July 2025, with construction on the generator building advancing in 2026 following environmental review and a Conditional Use Permit. In 2023, Helion signed the world's first fusion power purchase agreement with Microsoft to supply at least 50 MW starting in 2028 (with Constellation Energy as power marketer), including financial penalties for nondelivery; initial operations are targeted for 2028 to meet that commitment. A separate 2023 collaboration with Nucor targets development of a larger 500-MW plant at a steel facility by 2030. Orion establishes structural precedents for regulatory permitting, community engagement with Tribal nations and local stakeholders, and supply-chain scaling in a region with existing high-capacity transmission infrastructure.

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Polaris is Helion's seventh-generation prototype fusion machine, a 19-meter device completed and entering operation at the end of 2024 in Everett, Washington, built to demonstrate electricity production from fusion and validate scaling across fuel types ahead of commercial deployment. It features a 50+ MJ capacitor bank, peak magnetic fields exceeding 15 T, and high-efficiency recovery circuits enabling direct inductive recapture of energy from expanding Field Reversed Configuration (FRC) plasmas without a steam cycle. In January 2026 it became the first privately developed fusion machine to operate with deuterium-tritium (D-T) fuel, followed in February 2026 by the first measurable thermonuclear D-T fusion and a record plasma temperature of 150 million degrees Celsius—surpassing the prior 100 million °C benchmark set by its predecessor Trenta. The machine supports D-D, D-T, and D-He3 fuels to de-risk the aneutronic D-He3 cycle planned for commercial systems, with operational data directly informing Orion's design. As of mid-2026, testing continues toward the goal of showing fusion-driven electricity on the capacitor bank.

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TAE Technologies develops commercial fusion power using a beam-driven field-reversed configuration (FRC) approach in a linear reactor design, with a focus on aneutronic p-B11 fuel to minimize neutron production and radioactive waste. It competes directly with Helion through shared FRC plasma physics foundations and aneutronic ambitions, though TAE emphasizes steady-state or optimized beam-driven plasmas rather than Helion’s pulsed magnetic compression and direct electricity recovery. The company has built multiple generations of prototypes, recently achieving breakthroughs with its Norm machine that enable stable plasmas with reduced hardware complexity, and is actively evaluating U.S. sites for its first fusion power plant while shortening its device roadmap toward net energy and commercialization. Durable strengths include a substantial patent portfolio exceeding 2,300 filings, peer-reviewed publications validating performance gains, and diversified revenue streams from power management and BNCT cancer therapy spinouts that reduce single-point dependence on fusion timelines. TAE’s structural positioning benefits from partnerships such as the TAE Beam UK joint venture with UKAEA for accelerator commercialization and major investor backing including Chevron and Google, providing capital resilience amid long development cycles. Potential constraints relative to Helion include a more conservative timeline targeting early 2030s for initial plants versus Helion’s aggressive 2028–2029 grid delivery target, and reliance on neutral beam injection which introduces different engineering trade-offs in repetition rate and system integration. Recent developments, including a multi-billion-dollar merger announcement with Trump Media and Technology Group, underscore its scale in attracting strategic capital for power plant deployment.

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General Fusion pursues magnetized target fusion (MTF), a magneto-inertial approach that forms a magnetized plasma target and compresses it using mechanical pistons driving a liquid metal liner to achieve fusion conditions, explicitly designed as a practical, cost-competitive power plant architecture. It overlaps significantly with Helion in the magneto-inertial category, sharing emphasis on combining magnetic confinement with inertial compression for scalable energy production, though General Fusion’s liquid metal wall serves as first wall, neutron blanket, and tritium breeder in a more integrated plant design. The company operates its LM26 large-scale demonstration machine in Vancouver, advancing toward key milestones like the Lawson criterion to support a first-of-a-kind plant in the mid-2030s. Durable strengths lie in its long operational history of building and testing real prototypes over two decades, focus on addressing material degradation and fuel cycle challenges through liquid metal systems, and recent collaborations such as with General Atomics on diagnostics. Investor positioning is supported by its pursuit of public market listing and recognition as a top greentech company, providing pathways for sustained capital. Relative weaknesses versus Helion include a later commercialization horizon and mechanical compression mechanics that may introduce different repetition-rate or maintenance constraints compared to Helion’s electromagnetic pulsed system. The approach benefits from government-supported demonstration projects and collaborations.

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Zap Energy develops compact, modular fusion energy machines using a sheared-flow stabilized Z-pinch approach that confines and compresses plasma via electric currents without complex external magnets, targeting scalable, on-demand carbon-free power. It competes with Helion through a shared pulsed fusion paradigm and modular generator focus for grid or industrial customers, with both companies located in Washington state and pursuing similar buyer segments such as data centers and utilities amid rising AI-driven power demand. Recent milestones include achieving extreme plasma pressures validating the Z-pinch design, alongside DOE approval for fusion pilot plant preconceptual design. Durable strengths include the simplicity of its magnet-free architecture, which structurally reduces certain engineering complexities and costs, and an integrated strategy combining fusion with fission technologies for nearer-term revenue and risk mitigation. The company benefits from regional policy support in Washington for fusion development and DOE milestone-based funding programs that provide non-dilutive capital for pilot advancement. Constraints relative to Helion may include less emphasis on aneutronic fuels or direct energy conversion, potentially requiring more conventional energy recovery methods, and a development stage still focused on validation rather than active plant construction like Helion’s Orion. Its positioning emphasizes cost-effective scalability for diverse applications.

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Commonwealth Fusion Systems develops high-field tokamak fusion systems leveraging high-temperature superconducting (HTS) magnets co-developed with MIT to enable smaller, lower-cost reactors compared to traditional designs, with SPARC as the net-energy prototype and ARC as the follow-on commercial power plant. It competes with Helion as a leading contender in the race for commercial fusion electricity, sharing the goal of grid-scale clean power delivery to utilities and high-demand customers like data centers, though through steady-state magnetic confinement rather than Helion’s pulsed FRC method. The company maintains a strong manufacturing focus on HTS magnets at scale and has secured sites for commercial plants, including in Virginia. Durable strengths encompass the highest private funding in the sector, deep technical pedigree from MIT, and a broad investor base including Bill Gates and Google that supports long-horizon execution. Its tokamak foundation draws on decades of public research validation, providing a more conservative physics risk profile. Potential limitations versus Helion include reliance on a thermal steam cycle for energy conversion (lower efficiency than direct methods) and larger single-reactor scale rather than modular pulsed units, alongside a timeline projecting first power in the early 2030s. The approach benefits from global supply chain development for HTS technology with applications beyond fusion.

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Tokamak Energy advances commercial fusion through compact spherical tokamaks paired with high-temperature superconducting (HTS) magnets, aiming for globally deployable power plants with a pilot plant design targeting 800 MW fusion power and 85 MW net electricity output. It overlaps with Helion in pursuing practical electricity generation for the grid and industrial buyers, differentiated by its spherical tokamak geometry for higher efficiency at smaller scales versus Helion’s linear pulsed FRC. The company has achieved 100 million °C plasma temperatures in its ST40 prototype and is part of the U.S. DOE Milestone-Based Fusion Development Program, with design work progressing toward mid-2030s net power demonstration. Durable strengths include over a decade of tokamak and HTS magnet experience as a private entity, strategic U.S. subsidiary operations, and partnerships with national labs and universities that de-risk technology transfer. Its dual focus on fusion and HTS magnet commercialization provides structural revenue diversification. Relative to Helion, the approach may face challenges in achieving the ultra-high betas or direct conversion advantages of FRC systems and operates on a slightly later commercialization cadence. The spherical tokamak path leverages established magnetic confinement science while pursuing compactness for economic viability.

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Helion faces material execution and financial risk from its 2023 power purchase agreement with Microsoft, under which the company committed to deliver 50 MW or greater of fusion electricity from its first Orion plant by 2028 after a one-year ramp-up period, with financial penalties for nondelivery. The agreement, the first commercial fusion PPA, was announced in May 2023 and remains a cornerstone commitment referenced in subsequent funding and construction updates, exposing Helion to direct cash outflows and potential contract termination if timelines slip. Construction of the Orion plant near Malaga, Washington, began in 2025 on Chelan County PUD land following a Mitigated Determination of Non-Significance, with a Conditional Use Permit granted in October 2025 for the fusion generator building. However, the company's seventh-generation Polaris prototype—operational since late 2024 and re-focused on demonstrating electricity recovery to capacitors rather than full net grid power—has not yet published results confirming the required energy recovery milestone as of May 2026 reporting. This contractual structure creates asymmetric downside for investors, as penalties directly impact cash flow while the 2028 deadline anchors revenue expectations amid ongoing prototype validation. A concrete offset exists in the binding nature of the PPA itself, which demonstrates validated customer demand from Microsoft and involves Constellation Energy as power marketer, providing a tangible path to initial revenue if the timeline holds.

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Helion carries execution risk from repeated delays in demonstrating core technical milestones, including the original 2021 target of net electricity production from its seventh-generation Polaris prototype in 2024, which was not achieved. Polaris began operations at the end of 2024, achieved record 150 million °C plasma temperatures and measurable deuterium-tritium fusion in January 2026 as the first private machine to do so, yet no published results have confirmed net electricity generation or the targeted direct energy recovery to the capacitor bank as of May 2026. The company has since clarified Polaris goals away from full “net electricity” toward demonstrating partial fusion-driven energy return to subsystems, highlighting the gap between prototype performance and the commercial requirements for the 50 MW Orion plant. This pattern of timeline compression creates investor exposure to further delays in validating the pulsed FRC approach at repetition rates needed for grid power, directly threatening the 2028 PPA delivery and subsequent Nucor 500 MW development agreement targeted for 2030. No concrete, citable mitigant offsets the structural history of slippage, as recent DT fusion results advance physics validation but do not address the unproven commercial-scale energy recovery or continuous operation demanded by contracts.

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Helion faces key technical validation and execution risk from the public split with co-founder John Slough, whose FRC research formed the basis of the company’s magneto-inertial approach and who has criticized the viability of achieving required confinement and stability under Helion’s high-speed plasma merging and compression regime. In a May 19, 2026 Scientific American report, Slough described instabilities leading to “catastrophic” flux loss before sufficient fusion occurs and stated he “can’t see anything in the physics” supporting the D-He3 fuel cycle at the needed temperatures and confinement with the current design. This internal expert dissent directly undermines confidence in the unproven assumptions around plasma stability at commercial pulse parameters, direct energy recovery efficiencies above 95 percent, and the side-reaction breeding of He3 from D-D reactions that also produce tritium. The risk manifests as potential investor skepticism, difficulty attracting or retaining specialized talent, and challenges defending the technology thesis to future customers or regulators. No citable offsetting factor, such as peer-reviewed rebuttal data or independent validation of the disputed parameters, exists in available reporting to counter the structural concern raised by the foundational researcher.

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Helion is exposed to regulatory risk as the U.S. Nuclear Regulatory Commission continues developing its technology-inclusive framework for fusion machines, with a proposed rule published in the Federal Register on February 26, 2026, and public comment ongoing, creating uncertainty around licensing requirements for commercial-scale plants beyond initial state-level approvals. While Helion secured a Large Broad Scope license from the Washington State Department of Health for tritium use on Polaris in 2024, a Conditional Use Permit from Chelan County in October 2025 for the Orion generator building, and benefited from Washington House Bill 1018 in May 2025 classifying fusion distinctly from fission, the federal regime for byproduct material and fusion-specific licensing remains in flux under the ADVANCE Act amendments. This structural uncertainty could impose additional design, safety, or environmental reviews on Orion and future plants, delaying the 2028 grid connection or increasing compliance costs for the pulsed system’s capacitor banks, tritium handling, and neutron management. The first plant’s state permitting success provides a partial path, but the absence of finalized NRC rules for operational fusion devices leaves scaling dependent on an immature regulatory regime.

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Daniel Jassby and r/fusion users such as plasma_phys have long criticized Helion's FRC-based pulsed approach for inherent instabilities under compression, challenges with high beta and stability, unproven direct energy recovery at scale, heat flux/shielding issues in pulsed operation, and problematic D-He3 fuel cycle requiring net-loss D-D reactions producing tritium. A detailed 2025 r/fusion thread elaborates calculable red flags including FRC instability, beta=1 shielding preventing external coil coupling for recovery, subcritical D-He3 plasmas dominated by neutronic D-D fusion, and shielding/blanket incompatibilities with fast-ramped magnets. Former co-founder John Slough, in a May 2026 Scientific American article, sharply critiques the design: merging plasmas at extreme speeds drives instabilities causing "catastrophic" flux loss before fusion, with D-He3 ambitions physically implausible due to required heat and confinement. Karl Lackner's group published 2026 comments in the Journal of Fusion Energy arguing Helion's 2023 physics case (ion-electron temperature separation) becomes far more demanding once collisional transfer is accounted for. The 2018 JASON report is cited for simultaneous high compression and stability challenges. Recent Polaris D-T milestones (150M°C) are acknowledged but seen as incremental amid undemonstrated commercial steps like net electricity or stable high-gain operation. This technical skepticism is a dominant, recurring theme.

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r/fusion contributors including Anfros, joaquinkeller, and others emphasize Helion's minimal peer-reviewed output and restricted data access as blocking external validation, unlike standard plasma physics practice. Early prototype results had limited review, but absence of detailed spectroscopy, stability metrics, or full papers leaves claims untestable. Scientific American (May 2026) quotes Oak Ridge's Troy Carter noting the stance against publishing makes it "hard to fully assess where they’re headed." Geekwire coverage echoes that secrecy around proprietary elements hinders expert evaluation beyond announcements, amplifying doubts in a hype-prone field even as some defend commercial IP needs. This opacity theme recurs as a core enabler of broader skepticism.

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Outlets including Data Center Dynamics and Slate have long framed the Microsoft PPA (2028 delivery target) and large rounds as PR/investor signaling detached from deliverables, paralleling past fusion cycles and Theranos. r/fusion threads repeatedly invoke "Theranos" when highlighting the gap between bold promises and limited independent proof. Fortune coverage notes missed internal milestones (e.g., prior net-electricity targets) while timelines stay aggressive, with big-name backers like Sam Altman viewed by some as enabling narrative over rigorous validation amid AI power demand. The June 2026 $465M Series G at $15.5B valuation (nearly tripling prior) and OpenAI deal explorations have renewed such critiques in recent discussions, seen as serving short-term capital and market needs rather than de-risked technology. This view positions commercial milestones as narrative tools in a field with historical overpromising.

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A recurring minority view in r/fusion (e.g., joaquinkeller, Summarytopics, and others) holds that while risks are high and transparency limited, no fundamental scientific errors have been identified in public claims to date, early prototype results are reproducible in principle, and the pulsed FRC approach merits judgment via data from Polaris net-electricity attempts or Orion rather than preemptive dismissal. Some note field diversity benefits from any success and commercial iteration speed vs. traditional labs. This coexists with dominant skepticism but stresses waiting for definitive empirical results over 2025-2028 timelines, as reflected in balanced thread discussions and coverage acknowledging progress amid doubts.

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