Led · Series A · Apr 2026

Portal Space Systems is developing solar thermal propulsion engines that concentrate sunlight to heat propellant and enable higher-thrust, high-impulse maneuvers in orbit. Its Hex thruster integrates a combined solar concentrator and nozzle and the company cites advances in additive manufacturing and materials science as enablers. Portal has demonstrated flight electronics on a recent shakedown mission and plans an additional prototype launch in October, with a full engine demonstration on its SuperNova spacecraft targeted for 2027. The company highlights military demand for rapid orbital maneuvering and has received $45 million in strategic U.S. military funding alongside prior private capital. Financially, Portal raised a $50 million Series A at a $250 million valuation in 2024, supplementing earlier private raises. Founded in 2021, the company is led by Jeff Thornburg with co-founders Ian Vorbach and Prashaanth Ravindran.