Portal Space Systems is an emerging space startup based in Seattle, Washington that recently came out of stealth mode after raising over $3 million in funding. The company is developing innovative space technologies and spacecraft to enable a new era of ultra-mobile, responsive space operations.
Founded in 2021, Portal Space Systems is led by an experienced team with deep expertise from across the space industry.
Portal’s flagship product is a revolutionary new satellite bus called Supernova. Supernova aims to unlock unprecedented levels of maneuverability and mission flexibility with its cutting-edge solar thermal propulsion system. Solar thermal propulsion has long been researched but Portal is on track to be the first to implement it in an operational spacecraft.
While the company has not revealed specifics about Supernova’s propellant, it is described as non-toxic and storable on orbit, possibly similar to ammonia. The spacecraft will be payload-agnostic with a 500 kg capacity and is being designed from the ground up to maximize mobility.
Portal says Supernova will deliver an astounding 6 km/s of delta-v capability, over 50 times greater than existing satellites. Delta-v, which stands for change in velocity, is a crucial metric representing the impulse per unit of spacecraft mass. It’s often described as the “currency” of spaceflight.
To put Supernova’s 6 km/s spec into perspective, going from a stationary position to low Earth orbit requires around 9.4 km/s. An additional 6 km/s is then needed to reach the surface of the moon from low Earth orbit. Most satellites today have less than 500 m/s of delta-v, enough for only minor orbit adjustments and collision avoidance maneuvers.
Supernova’s massive delta-v will enable dynamic new mission capabilities not possible with current satellite buses:
- Rapid orbit changes: Supernova will be able to transition from low Earth orbit to geostationary orbit 35,786 km above the Earth in a matter of hours. Reaching the moon will take just days.
- Responsive operations: Satellites will be able to make major trajectory changes to respond to emerging needs or threats in near real-time, no longer locked into their initial orbits.
- Extended mission life: With ample delta-v to spare, Supernova-based satellites can perform more maneuvers and orbit changes over a longer lifespan before exhausting propellant.
- Refuelable constellation: Portal envisions pre-positioning Supernova spacecraft in key orbits like MEO and GEO to provide on-demand mobility, resupply, and other servicing to client satellites.
Portal is targeting both commercial and government customers with Supernova’s disruptive capabilities. The company sees on-orbit logistics and satellite servicing as key enablers for the growing space economy. Supernova could also be a game-changer for military space operations, providing the Space Force with unmatched resiliency and tactical agility.
The U.S. Space Force seems to agree, having already awarded Portal over $3 million to support Supernova’s development. The funding underscores the government’s interest in responsive space systems and the startup’s potential to advance national security space capabilities. Portal says it is working closely with government partners to ensure Supernova meets their mission needs.
Portal has made rapid progress since spinning up in stealth mode in late 2021. Thornburg and team have been heads down working to de-risk Supernova’s novel solar thermal propulsion technology and refine the spacecraft’s design. With millions in funding locked in, Portal is now sprinting towards the first launch of a Supernova vehicle, targeted for late 2025.
The space startup scene has seen a surge of activity in recent years, with dozens of new entrants pursuing everything from small launch vehicles to satellite constellations to lunar landers. Portal Space Systems stands out from the pack with its unique focus on in-space mobility and its all-star cast of industry veterans.
As the company transitions into public view, more details will likely emerge about Supernova’s specific technical approach and Portal’s go-to-market strategy. But it’s already clear that Portal has the potential to be a major disruptor in the industry.
If Portal can deliver on Supernova’s ambitious performance specs, it could spark a mobility revolution in Earth orbit and beyond, enabling new markets and mission paradigms. Real-time responsiveness, flexible constellations, and on-demand servicing could become the new norm as satellites break free from the constraints of their initial trajectories.
Portal’s longer-term vision also points to an exciting future of sustainable in-space operations, with Supernova’s high efficiency solar thermal propulsion and refueling capabilities setting the stage for more infrastructure development in cislunar space. As the space economy expands to the moon and one day Mars, logistics vehicles like Supernova could become the backbone of an interplanetary highway system.
Of course, Portal still has much to prove. Developing a high delta-v spacecraft with a first-of-its-kind propulsion system is a hugely complex undertaking with significant technical risk. Incumbent satellite operators may also be slow to embrace radically new architectures after decades of gradual, evolutionary progress. Portal will need to demonstrate not just Supernova’s technical viability but also a compelling business case for ultra-mobile spacecraft.
But with a seasoned team, substantial funding, and a bold vision, Portal Space Systems is well positioned to pioneer a new era of space mobility. The startup’s emergence is a signal that the pace of innovation in the space sector continues to accelerate, with profound implications for science, commerce, and security. As Supernova takes shape, all eyes will be on this Seattle upstart and its promise to unleash the untapped potential of agile spacecraft. The space mobility race is on.
