Muon Space is a Mountain View, California small satellite maker founded in 2021 that offers space systems as a service, building and operating constellations on its vertically integrated Halo platform with infrared and radio frequency instruments developed in-house. Its first satellite, MuSat-1, launched in 2023 and was deorbited at the end of 2024; MuSat-2 carries instrumentation supporting Department of Defense weather programs. A third satellite launched in March 2025 as the protoflight for FireSat, a low Earth orbit wildfire detection and response constellation developed with the nonprofit Earth Fire Alliance and supported financially by Google Research. Announced customers include the National Reconnaissance Office, Space Force, Space Development Agency, Hydrosat and Sierra Nevada Corporation. A 12,000 square metre production facility in San Jose is designed to support up to 500 satellites per year in the 100-500 kg class, and headcount reached about 150 in mid-2025.
Funding
Muon Space announced $89.5 million in new funding on 12 June 2025, comprising $44.5 million in equity and $45 million in credit facilities, led by Congruent Ventures with new investor ArcTern Ventures and existing investors Activate Capital, Acme Capital, Costanoa Ventures and Radical Ventures. The company said this brought its total Series B funding to $146 million, following $56.7 million raised the prior year. The round also funded the acquisition of propulsion startup Starlight Engines.