The era of stationary spacecraft may soon be over.
Portal Space Systems, a company led by propulsion expert Jeff Thornberg, aims to usher in a new renaissance in space transportation with its ultramobile Supernova satellite bus. Think of it as maneuverability as a service – a technology that could enable transfers from low Earth orbit to geostationary orbit in a matter of hours.
The 500kg Supernova is designed to be payload independent and survive in orbit for at least five years while being continuously maneuvered, the company said. It’s a far cry from traditional spacecraft, which only have as much propulsion as needed to maintain their orbit. Portal has developed a novel propulsion system called solar thermal propulsion that will generate a massive delta-V of 6 kilometers per second to enable rapid transfer to cislunar space or to serve as a maneuverable facility in support of national security missions.
Portal was founded by space veterans Jeff Thornburg, COO Ian Vorbach and VP of Engineering Prashaanth Ravindran. Thornburg’s career reads like a grand history of the space industry. It spans nearly 30 years and includes stints at virtually every major aerospace organization: as a military officer in the Air Force; working on liquid rocket engine technology at Aerojet; five years at SpaceX, where he eventually became second vice president of propulsion; Collaborated with famed entrepreneur Paul Allen on Stratolaunch; and as a director on Amazon’s Project Kuiper.
“Then I decided that I didn’t really want the big company lifestyle and I really wanted to address some problems that weren’t being addressed by any other company, and so my co-founders and I founded Portal Space Systems in November 2021,” he said . “It’s the only time I feel like I can predict the future, even remotely.”
Having spent most of his career developing and propelling launch vehicles, he began thinking about what was next in the industry after SpaceX cracked the code to affordable, fast and reliable launch. He also noted other trends: As more spacecraft are put into orbit than ever before, orbital collisions are becoming more likely. On the defense side, Thornburg also began to see greater national security interest in responsive space capabilities and the ability of satellites to maneuver “without remorse.”
But satellites aren’t designed to move around much in orbit; Generally, they are launched with enough onboard propulsion to keep them in their intended orbit, not to avoid other objects, and certainly not without Delta-V capability to get to a higher orbit. Supernova is part of a new generation of spacecraft that aims to change that.
The company developed Supernova’s propulsion system itself. The solar thermal system leverages legacy technologies developed by NASA and the Department of Defense while developing specific subsystems to optimize mission performance. For example, the company incorporates a proprietary heat exchanger into this solar thermal propulsion system to achieve even higher performance over a longer lifespan.
“I think the big driver here for commercial use is just the proliferation of these LEO constellations that need to be maneuvered around, and the driver for the Department of Defense is China and the future engagement that people believe we have with them.” Taiwan and other topics. Both things came together at the same time, creating the opportunity that I was hoping for but didn’t quite anticipate would be so significant.”
Portal has raised an undisclosed amount of venture capital from undisclosed backers and the first Supernova development is fully funded, the company said. The team has also won over $3 million in five Space Force and DOD awards, including a Direct-to-Phase II SBIR specifically focused on developing responsive space operations.
Portal intends to conduct a flight demonstration in late 2025 or early 2026. But before that mission even launches, Thornburg says the startup wants to grow its team – which is currently about 25 people but is expected to grow to up to 200 in 25 years – and expand production to include production of multiple spacecraft per spacecraft after this initial demonstration year to support.