Portal Space Systems, a next-generation spacecraft company headquartered in Washington state, has successfully tested a solar thermal propulsion (STP) system at operational temperatures inside a vacuum chamber – validating the core technology powering Supernova, Portal’s multi-role spacecraft built for space superiority through rapid maneuverability and long-duration missions.
The test campaign, conducted at Portal’s Bothell, WA facility, demonstrated full-power, high-temperature operation of the company’s patented, 3D printed heat exchanger (HEX) thruster, confirming predicted performance under flight-like conditions. This HEX Thruster, named ‘Flare’, will enable maneuverability from LEO to MEO in a few hours, MEO to GEO in under a day, and LEO to Cislunar space in just a few days, all using a single, non-cryogenic, storable monopropellant: ammonia.
“With maneuverability becoming a defining advantage in space operations, Supernova is built to give national security and commercial operators the ability to reposition, respond, and persist across orbits,” said Jeff Thornburg, CEO of Portal Space Systems. “This propulsion system unlocks mission tactics and timelines that traditional chemical or electric systems simply can’t support.”
While solar thermal propulsion has been studied and under experimentation since the 1960s by NASA and the Air Force, it has remained, for the most part, a research effort. Portal is one of the first commercial companies to bring the concept to life in a flight-representative environment by leveraging additive manufacturing, advanced materials, and a novel heat exchanger to make STP viable for real-world missions.
Unlike traditional systems built to hold position, Supernova is designed to move – supporting real-time responsiveness and persistent presence across LEO, MEO, GEO, and Cislunar orbits. With no combustion required and using a non-cryogenic propellant, Portal’s propulsion architecture also supports refuelability and an over 5-year life in orbit.
During testing, the system achieved: full-power test of Portal’s HEX Thruster (Flare) in vacuum; high-temperature performance of its patented, 3D printed heat exchanger; predicted thrust and Isp verified under flight-representative conditions; fully instrumented campaign including cold flow, calibration, and high-temperature sequences; facility brought online to simulate solar energy via high-power electric heating; and propulsion architecture validated for integration with future flight hardware.
