Startups look to add electronic-threat detection to maneuverable spacecraft. August 25, 2026 Two of TFX's Portfolio Companies, Portal Space Systems and Rebel Space, are teaming up to put spectrum monitoring technology aboard Portal's vehicles, extending a capability now used on the ground into orbit. The companies are exploring several approaches that would allow Portal spacecraft to detect and characterize interference and other electronic threats in their immediate surroundings, executives from the two startups told SpaceNews. One option is a dedicated Rebel payload. Another would integrate the technology as a standard onboard function, giving Portal spacecraft continuing awareness of the radio-frequency environment while carrying out other missions. The effort comes as government agencies and commercial satellite operators pay closer attention to the increasingly congested electromagnetic environment in space, where communications links can be disrupted by unintentional interference or deliberate jamming. Rebel provides spectrum intelligence from the ground by connecting its hardware and software to antennas operated by independent satellite teleport companies. Its systems analyze the RF signals received by those antennas to identify and characterize interference and jamming, and can help attribute or potentially geolocate their source. Carrie Marshall, Rebel's chief executive, said the company now wants to move that sensing and analysis closer to the spacecraft itself. That could give satellite operators a more immediate picture of what is affecting a communications link rather than relying solely on observations from ground stations. For military spacecraft operating in a contested environment, onboard monitoring could also help identify attempted jamming, suspicious commands or other unusual electromagnetic activity. Marshall said one approach under discussion is a "spectrum warfare" payload hosted by Portal. Such a system could provide not only analytics but the ability to "respond in kind or actively defend or mitigate" activity affecting the spacecraft. The companies are also considering embedding Rebel's technology more broadly across Portal's spacecraft rather than treating it as a standalone payload. Portal's chief executive Jeff Thornburg said the company is interested in an "ingrained capability to understand the EW environment around the spacecraft." That approach could be useful for Portal's spacecraft, which are being designed to maneuver more extensively than traditional satellites. A vehicle moving toward another spacecraft or into a different orbital region may need to understand the local RF environment without waiting for ground-based sensors to provide that picture, Thornburg said. The capability could also support space domain awareness, the military term for detecting and understanding objects and activity in orbit, by adding information about electromagnetic activity to optical and other forms of tracking. The companies are looking to begin integration work on the ground. "The next step for Carrie and me is really to marry her hardware and software with our system and test it in our hardware-in-the-loop system on the ground before the first launch, which would probably be no earlier than 2027," Thornburg said. Portal launched its first hardware in March aboard SpaceX's Transporter-16 mission, flying a small technology-demonstration payload that tested the flight computer, avionics and software intended for its spacecraft family. Its next milestone is the first flight of Starburst, Portal's roughly 300-kilogram maneuverable spacecraft, scheduled to launch in October aboard SpaceX's Bandwagon-5 rideshare mission to a mid-inclination orbit. The inaugural flight is intended primarily to validate the Starburst design. It will also carry rendezvous-and-proximity-operations cameras supplied by TRL11 and a superconducting magnet technology payload from Zenno Astronautics. Starburst will also be the first orbital deployment of Atomic-6's Space Armor, a lightweight composite tile system designed to protect spacecraft from micrometeoroids and orbital debris.