Start-up capabilities of photovoltaic module for the International Space Station

Abstract

The International Space Station (ISS) uses four photovoltaic modules (PVMs) to supply electric power for the US On-Orbit Segment (USOS). The ISS is assembled on-orbit over a period of about 5 years and over 40 stages. PVMs are launched and integrated with the ISS at different times during the ISS assembly. This paper describes the essential steps required for PVM start-up and how these operations are performed for various PVMs. The integrated operations scenarios (IOS) prepared by the NASA, Johnson Space Center, details specific procedures and timelines for start-up of each PVM. The paper describes how dormant batteries are brought to their normal operating temperature range and then charged to 100% state of charge (SOC). Total time required to complete start-up is computed and compared to the IOS timelines. External power required during start-up is computed and compared to the requirements and/or available power on ISS. Also described is how these start-up procedures can be adopted for restart of PVMs when required.