Portal Space Systems

Portal Space Systems is a spacecraft and propulsion startup headquartered in Bothell, Washington, developing a high-delta-V space mobility platform called Supernova. The vehicle is designed around a solar thermal propulsion system that concentrates sunlight to superheat propellant, targeting orbit-to-orbit maneuvers substantially beyond the reach of conventional chemical smallsat buses.

Founded by Jeff Thornburg (formerly chief engineer on SpaceX's Raptor engine program) in 2021, Portal is positioning Supernova for responsive space logistics — rapid orbit changes, inspection, servicing, and rendezvous missions for commercial and national-security customers. The company has received SBIR and Strategic Funding Increase awards from the U.S. Space Force's SpaceWERX and raised private seed and Series A rounds from investors focused on defense technology.

Portal's strategy is to bridge the gap between low-impulse electric smallsat buses and larger chemical space tugs, offering months-long maneuvering lifetimes without the complexity of cryogenic chemical propulsion. The company has announced plans for an initial Supernova flight demonstration later in the decade.