Juno Propulsion Raises $1.4 Million Pre-Seed Round to Advance First On-Orbit Demonstration of RDC-Powered Spacecraft Propulsion
TUKWILA, Wash. — June 8, 2026 — Juno Propulsion today announced the successful close of a $1.4 million pre-seed financing round led by SOSV, with participation from Hypernova Fund, Leslie Ventures, Activate, Collaborative Fund, Safar Partners, and Cape Fear Ventures.
The financing will support development and flight qualification of Project IRIS, Juno’s rotating detonation combustion (RDC) propulsion system. The company is preparing to be the first on-orbit demonstration of an RDC-powered spacecraft propulsion system, with launch currently targeted for the first quarter of 2027.
Project IRIS is a 45-newton spacecraft propulsion system powered by non-toxic propellants, nitrous oxide and ethane. The system is designed to deliver approximately 100 meters per second of delta-v while achieving performance exceeding state-of-the-art chemical propulsion technologies. Juno’s RDC architecture has demonstrated efficiencies greater than conventional combustion approaches, offering the potential for higher-performance propulsion with inherent system simplicity.
Project IRIS is also supported through NASA’s TechLeap Prize program. In 2025, Juno was selected as one of ten winners of NASA’s Space Technology Payload Challenge, receiving a $500,000 award to advance the flight demonstration. The award additionally funds launch and flight-provider services for the mission. Juno recently completed Build Round 2, the program’s final major development checkpoint before flight preparation.
“This financing marks a major milestone for Juno as we move from ground testing to flight hardware and mission execution,” said Dr. Alexis Harroun, co-founder and Chief Executive Officer of Juno Propulsion. “Project IRIS represents an opportunity to demonstrate a fundamentally new propulsion architecture in space. With the support of our investors and NASA’s TechLeap program, we are positioned to prove RDC technology on orbit and unlock new capabilities for future spacecraft.”
Founded by Dr. Alexis Harroun and Dr. Ari Martinez, Juno Propulsion is developing advanced propulsion systems based on rotating detonation combustion, a technology that harnesses continuously propagating detonation waves to extract more useful work from chemical propellants than conventional combustion systems. The company is demonstrating how RDC technology can enable a new class of efficient, high-performance propulsion solutions for commercial and government spacecraft.
Since receiving the NASA TechLeap award, Juno has expanded to a team of five employees and completed activation of its propulsion test facility in Tukwila, Washington. The facility provides in-house capabilities for propulsion development, testing, and qualification as the company advances toward its orbital demonstration mission.
“Propulsion technology is a critical enabler of the United States technological capabilities in space and on earth. Juno is leading the way in this field with their rotary detonation propulsion technology. We're proud to support them and impressed by the rapid progress,” said Andy Gollach, Partner at SOSV Ventures.
With the new capital, Juno will continue system development, testing, integration, and mission preparation activities for Project IRIS ahead of its planned 2027 launch. The company also expects to expand its engineering capabilities as it works toward future commercial and government applications of RDC-powered propulsion systems.
About Juno Propulsion
Juno Propulsion is a rocket propulsion company headquartered in Tukwila, Washington. Founded by Drs. Alexis Harroun and Ari Martinez, the company develops rotating detonation combustion propulsion systems for spacecraft applications. Through Project IRIS, Juno is pursuing the first on-orbit demonstration of an RDC-powered spacecraft propulsion system, utilizing green propellants and advanced combustion technology to deliver high-performance in-space mobility.
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