Polaris is Helion's seventh-generation pulsed FRC/magneto-inertial prototype, intended to demonstrate electricity recovery directly from fusion. In early 2026 Helion reported 150 million °C plasmas and measurable D-T fusion, the first by a private company.
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Current state
| Status | Operating |
| Country | United States |
| Location | Everett, Washington |
| Developer | Helion Energy |
| Developer type | Private |
| Concept | Field-reversed configuration |
| Fuel | D-He3 |
| Purpose | Demonstration |
| First plasma | 2024-12 |
| Private funding raised | USD 1.5bn (as of 2026-06-04) |
| Public funding | DOE Milestone-Based Fusion Development Program awardee |
| Regulation | Received Washington State approval to possess and use tritium for D-T operation. |
Notes
Helion says it began operating Polaris at the end of 2024 (first plasma given at month precision). Commercial fuel is D-He3 (not yet achieved); D-T runs were diagnostic. Helion has not published a Q target or electricity-recovery measurements for Polaris.
Timeline
- 2026-01 — Polaris produced measurable deuterium-tritium fusion, which Helion says is a first for a privately developed machine. (source)
- 2026-02-13 — Helion reported Polaris plasma temperatures of 150 million °C (~13 keV), beating its prior 100 million °C record. (source)
- 2026-06-04 — Helion raised a $465 million Series G at a $15.5 billion valuation, bringing total invested capital to $1.5 billion. (source)
The timeline is append-only: corrections are added as new entries. Stated targets appear in the current-state table, never as milestones.
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Sources
- Helion Achieves New Industry-First Fusion Energy Milestones — Helion Energy (primary), checked 2026-10-11
- Fusion startup Helion hits blistering temps as it races toward 2028 deadline — TechCrunch, checked 2026-10-11
- Helion Raises $465 Million Series G Funding Round — Helion Energy (primary), checked 2026-10-11
- Microsoft-backed fusion firm Helion raises $465m in Series G — DatacenterDynamics, checked 2026-10-11