Muon Space has closed their oversubscribed $89.5 million Series B1 round, bringing total Series B funding to $146 million—this new capital includes $44.5 million in equity and $45 million in credit facilities, and follows the company’s initial Series B close in August of 2024.
The B1 round was led by Congruent Ventures and included existing investors—Activate Capital, Acme Capital, Costanoa Ventures, and Radical Ventures. Muon also welcomed new investor ArcTern Ventures to the syndicate.
The new capital is fueling a major scale-up of Muon’s operations—including expanded satellite production; vertical integration of key components such as propulsion and IR and RF instruments; deployment of Muon’s full-stack automated constellation operations platform; and the expansion of the company’s global ground station network.
The company has grown its team by 50% since December and has surpassed $100 million in new contracts signed in 2024, including a landmark agreement with SNC to develop next-generation satellites supporting its Vindlér commercial RF sensing constellation.
Muon has also acquired Starlight Engines, a propulsion startup pioneering the first commercially available solid propellant Hall-effect thruster systems—a safe, affordable, and scalable alternative to traditional propulsion systems. The acquisition further extends Muon’s vertically integrated Halo™ platform by bringing in-house propulsion capabilities into its end-to-end satellite technology stack.
Founded in 2022 by veteran propulsion experts Todd Bailey and Mark Hopkins, Starlight developed a novel zinc-fueled thruster system that eliminates the high costs and supply chain vulnerabilities of xenon and krypton-based systems. By eliminating high pressure fluids management—the Achilles heel of every space propulsion system—Starlight’s technology enables a dramatically improved supply chain, highly available and low-cost propellant, simplified integration, and more compact thruster and tank designs. The thruster system scales modularly supporting spacecraft ranging from 100kg to 500kg+. Integration of Starlight’s propulsion technology is already underway as Muon scales satellite production.
Muon has opened a 130,000-square-foot facility in San Jose, California that will serve as its production center, housing manufacturing and test operations from raw material through finished spacecraft. Purpose-built for full vertical integration and high-throughput satellite production, the facility can support up to 500 satellites annually in the 100kg to 500kg+ class.
The site features 70,000 square feet of manufacturing facilities including 30,000 square feet of cleanroom space across Class 10, 1,000, 10,000, and 100,000 environments—a 10x expansion from Muon’s first facility. The flexible layout accommodates production, assembly, and lab operations, with dedicated areas for secure integration, spacecraft assembly, optical instrument integration (three zones), propulsion integration, and a mission operations center. A 300 kW solar array powers the majority of operations, while the facility meets UL 2050 security standards for defense programs.
Comprehensive environmental testing capabilities include thermal vacuum chambers, vibration tables, and thermal chambers for both unit- and system-level qualification.
Propulsion remains one of the most persistent cost and supply chain challenges in satellite manufacturing,” said Paul Day, VP of Spacecraft Production at Muon Space. “What Todd and Mark have achieved at Starlight is a fundamentally more elegant and practical solution – solid-state, scalable, throttleable, and safer to handle. By bringing this technology in-house and integrating it into our Halo platform, we can accelerate delivery timelines while improving both schedule reliability and overall mission performance.”
We’re focused on delivering mission-optimized satellite constellation systems to customers at unprecedented speed,” said Jonny Dyer, CEO of Muon Space. “High-performance constellations require the speed, cost, consistency, and performance of volume production – they can’t be built one satellite at a time. We are building the world’s first automated, high-mix, high-volume constellation manufacturing system. It’s always been about the mission – now we’re delivering it at scale.”
Muon is building the high-performance scale solution the space industry has been missing,” said Joshua Posamentier, Managing Partner at Congruent Ventures. “By fulfilling mission requirements with a configurable, vertically integrated platform spanning hardware, software, and operations, they deliver a unique path to on-orbit capabilities – at a pace and price point that commercial, civil and national security customers urgently need.”
