Portal Space Systems Secures $17.5M to Develop Revolutionary Trans-Orbital Spacecraft

Insider Brief

• Portal Space Systems has raised $17.5 million in a successful seed round to accelerate the development of Supernova, a next-generation spacecraft designed for complex space operations.
• This funding, led by AlleyCorp and joined by other strategic investors, will help Portal Space Systems reach key milestones, including a critical design review and propulsion testing set for 2025.
• The company plans to launch its first full-scale demonstration of Supernova in mid-2026.

Portal Space Systems, a Seattle-based space startup, announced it has raised $17.5 million in a successful seed round to accelerate the development of Supernova, a next-generation spacecraft designed for complex space operations. This funding, led by AlleyCorp and joined by other strategic investors, will help Portal Space Systems reach key milestones, including a critical design review and propulsion testing set for 2025. The company plans to launch its first full-scale demonstration of Supernova in mid-2026.

Supernova is a multi-role, trans-orbital spacecraft capable of maneuvering between different orbital environments, from Low Earth Orbit (LEO) to cislunar space, in a matter of days. This capability makes it highly suitable for both defense and commercial applications that require flexibility and rapid repositioning. The spacecraft’s design incorporates Portal’s proprietary solar thermal propulsion (STP) system, which mimics the performance of nuclear thermal propulsion without the need for a fission reactor. As a result, it offers improved maneuverability and long-range mobility while significantly reducing cost, risk, and regulatory hurdles.

Jeff Thornburg, CEO of Portal Space Systems, emphasized the importance of this breakthrough: “Our vision is to provide next-gen spacecraft that today’s space operations demand and our nation deserves,” he said. “This funding is a testament to the increasing recognition that maneuverability at will is the critical need in both defense and commercial space operations.”

Supernova’s unique propulsion system also enables it to perform extended missions, with a potential operational lifespan of up to five years. This capability, combined with software-enabled payload flexibility and compatibility with multiple launch providers, positions Supernova to address a wide range of mission needs, from satellite servicing to defense and scientific exploration.

The seed funding will support the completion of Supernova’s design review and propulsion testing in the coming months, with system integration set to begin in late 2025. The first demonstration mission is scheduled for mid-2026.

The company’s leadership team, including veterans from SpaceX, Stratolaunch, and Kuiper, has expanded rapidly as Portal prepares to scale its operations. With the backing of both commercial investors and government funding from the U.S. Department of Defense and Space Force, Portal is positioned to lead the next generation of spacecraft capable of operating in contested and congested space environments.

Image credit: Portal Space Systems