Portal Space Systems is building maneuverable orbital spacecraft for defense, with first Starburst mission launching October 19

Portal Space Systems

Jeff Thornburg spent more than 30 years in the space industry, including time at SpaceX, before founding Portal Space Systems on a straightforward provocation: the US runs its spacecraft like hot air balloons while adversaries run theirs like fighter jets.

The core technical bet is maneuverability. Most satellites in orbit follow predictable paths, which means adversaries can anticipate them, cover assets, and avoid surveillance. Portal is building spacecraft that can move unpredictably and frequently, without being constrained by fuel. Thornburg frames the current paradigm as buying a car and scrapping it after the first tank of gas. Portal's systems are designed to eliminate that constraint.

The defense framing is explicit. China and Russia are increasingly active in the space domain, and Thornburg argues that controlling that domain is as strategically necessary as controlling land, air, and sea. He points to a 60 Minutes report documenting Chinese tactics against the Philippine Navy in the South China Sea as a public reference point for the kind of adversarial behavior Portal is built to counter.

“We're running our spacecraft like hot air balloons and adversaries are running theirs like fighter jets. We really set out to build the fighter jets for orbit. We're about 60 people north of Seattle. We launched our first mission to orbit in March. We just finished our first small Starburst spacecraft, about 600 pounds, going up to demonstrate our ability to maneuver — launching October 19.”

Progress and timeline

Portal, headquartered north of Seattle, has grown to 60 people. The company launched its first mission to orbit in March to test electronics hardware. Its first Starburst spacecraft, weighing roughly 600 pounds, is scheduled to launch October 19 to demonstrate on-orbit maneuverability. The team was preparing to ship the vehicle to Cape Canaveral within days of this conversation.

Defense procurement shift

Thornburg sees the acquisition environment improving. The Department of Defense has been pushing to break up legacy information compartmentalization and get capability to warfighters faster, which has made defense agencies more willing to partner with commercial companies. Portal sits squarely in that opening.

On the question of public transparency around space conflict, Thornburg expects more companies like Portal to emerge with significant defense revenue, but national security constraints mean the details of on-orbit incidents are unlikely to become fully public.

The lesson he carries from SpaceX is tenacity, paired with a calm disposition under pressure. Running around with your hair on fire, he argues, is not how you inspire confidence in a team solving hard problems.