Hermes Small Satellite Bus

General Atomics Electromagnetic Systems (GA-EMS) is the space and defense electronics division of General Atomics Corporation, a US science and technology company. GA-EMS produces the Hermes small satellite bus, a modular 100–500 kg class satellite platform designed for US government and commercial payloads in low and medium Earth orbit.

The Hermes bus provides a space-qualified structure, electrical power system (deployable solar arrays), thermal management, on-board computer, and communication system that can accommodate a wide variety of government and commercial payloads. The bus design is optimized for DoD missions requiring radiometric performance, cryptographic electronics compatibility, and US-origin supply chain compliance — requirements increasingly important for national security satellite programs.

GA-EMS also supports the US Space Force’s proliferated LEO (pLEO) vision, providing satellite platforms and hosted payloads for space domain awareness missions. The company has legacy in electromagnetic launchers (railguns), fusion energy research, and nuclear technologies — with its satellite division applying systems engineering expertise from these programs to space. GA-EMS is headquartered in San Diego, California.