Bothell, Wash.-based Portal Space Systems has raised $50 million in a funding round aimed at speeding up development of the Seattle-area startup’s highly maneuverable space vehicles.
The first such vehicle, Starburst-1, is due for launch as early as this fall as a payload on SpaceX’s Transporter-18 satellite rideshare mission. Portal is also getting ready to move into a 52,000-square-foot manufacturing facility where future Starburst spacecraft and even more capable Supernova space vehicles will be built.
Portal CEO Jeff Thornburg — who co-founded the company in 2021 following stints at tech ventures including SpaceX and Stratolaunch Systems — characterized the newly announced Series A funding round as closer to a giant leap than a small step.
“The thing that’s exciting me the most, and really the company at large, is that it helps us move faster,” he told GeekWire. “We’re obviously focused on getting Starburst and Supernova capabilities demonstrated and available to our customers as quickly as we can.”
The round was led by Geodesic Capital and Mach33, with participation by Booz Allen Ventures, AlleyCorp and FUSE. It builds on a $17.5 million seed round that was announced last year.
Portal is developing a solar thermal propulsion system that will use focused sunlight to heat the ammonia-based propellant for its Supernova space vehicle. The system is designed to allow for rapid adjustments in Supernova’s orbit. Orbital maneuvers that would typically take weeks or months to execute using traditional propulsion systems could be done in hours or days.
Starburst would use a more traditional thruster system, but would take advantage of many of the technologies being developed for Supernova. “Eighty-one percent of the components are shared between Starburst and Supernova,” Thornburg said. “We’ve got a lot of delta-v packed in the Starburst, even though it’s a smaller platform.”
Starburst-1, which is being readied for a potential October launch, will be equipped with TRL11’s video camera and edge processing system plus Zenno Space’s superconducting magnetic actuator for a yearlong test mission in sun-synchronous orbit.
An experimental payload nicknamed “Mini-Nova” was sent into orbit last month to test the control software and power systems for Starburst as well as for Supernova. “Mini-Nova is healthy … and so I think we’re in good shape for what’s to come,” Thornburg said.
The first Supernova is due to be launched next year, thanks in part to $45 million in funding from the U.S. Space Force’s SpaceWERX program. Thornburg said Supernova-1 could take on any of a variety of missions that “support the Defense Department’s needs where it comes down to rapid maneuverability.”
Portal’s team is already looking further out on the mission timeline.
“We have a lot of interest from a lot of different customers, including the government just by itself, as well as commercial companies in the service of defense or commercial missions,” Thornburg said. “So, we’re leaning forward on the second Starburst build. And then, in parallel, one of the first uses of the new building will be assembly work for Supernova-1. … We can continue to build Starburst in our existing facility if we want to, for a certain amount of time.”
Portal is aiming to build as many as four spacecraft per month by the end of 2027 — which means the company is going to need a bigger workforce. “We’re at about 40 people at the company,” Thornburg said. “We’ll probably double in size throughout the rest of this year.”
How would Starburst and Supernova be used? “For defense, what we’re really targeting is areas I would describe as space domain awareness, or being able to observe things that sometimes can be difficult to observe,” Thornburg said. “And then I think the second application in the defense category is to protect and defend. We have adversaries on orbit doing things that are very confrontational, and I don’t know that we always have equivalent capabilities or deterrence in kind.”
On the commercial side, Thornburg points to orbital debris tracking and removal. “Recently you had a Starlink satellite breaking up,” he said. “That creates a problem for SpaceX and other people. Having to move around this stuff costs money and time. So, you’re seeing a profit motive for dealing with orbital debris on the commercial side, as well as their own surveillance.”
Portal and an Australian venture called Paladin Space recently announced a partnership to create an orbital debris tracking and removal service that could go into business as early as next year. Starlab Space, an industry consortium that has been laying the groundwork for a commercial space station, has already signed a letter of intent to integrate the Portal-Paladin service into future station operations.
Thornburg said Supernova could also play a role in NASA’s Artemis moon program, which recently set its sights on building a permanent lunar base. “We have the performance to be able to easily move between GEO [geostationary Earth orbit] and cislunar domains in a way that could be helpful for logistics, experiments, communications, data and other things. We don’t have a lot of spacecraft that can do that without the aid of a rocket right now,” he said.
In all these cases, Portal aims to capitalize on its ability to offer rapid mobility in space — a strategy that received strong backing from the company’s leading investors. “We are confident that Portal will become the Space Mobility Prime in the near future,” said Aaron Burnett, group CEO of Mach33.
“The future of space is dynamic, and that shift is being recognized globally,” said Rayfe Gaspar-Asaoka, partner at Geodesic Capital. “Portal Space is pairing deep propulsion expertise with advanced spacecraft development built for mobility, reliability and scale. Geodesic is thrilled to co-lead Portal’s Series A and work alongside Jeff and the team as they continue to expand what’s possible in space.”
