A solid state power controller module for the international space station express rack

The Solid State Power Controller Module (SSPCM) designed for the International Space Station (ISS) EXPRESS Rack is a remote-controlled power switching unit with both 120V de and 28V de Solid State Power Controllers (SSPCs). The SSPCs distribute and protect power to the various loads within the EXPRESS Rack. The SSPCM is designed with two 120V de inputs (Main and Auxiliary) and includes three 1100W DC/DC converters to provide the payload 28V de. The Main 120V de bus normally provides the 120V de for the payloads and the DC/DC converters. In the event of an undervoltage condition on the Main 120V de bus, the SSPCM automatically switches the payloads and the DC/DC Converters to the Auxiliary 120V de bus. The SSPCM can be configured on orbit to control which payloads are powered during Auxiliary 120V de operations. This allows an experiment system to run without crew actions during numerous mission profiles. The SSPCM also provides payload analog and discrete inputs/outputs for experiment use. The SSPCM provides sampling rates up to 1 khz and data formatting for payload data. Two additional configurations consisting of more power channels and less payload analog and discrete inputs/outputs are also under development for the International Space Station Furnace Facility.