AXAF-I Electrical Power System breadboard simulation testing

Electrical Power System (EPS) breadboard simulation testing for the Advanced X-ray Astrophysics Facility-Imaging (AXAF-I) spacecraft is being performed at NASA´s Marshall Space Flight Center (MSFC). This real-time testing will verify functionality of software control routines and where possible, operation of flight type hardware. The breadboard completely encompasses the AXAF-I EPS allowing contingency simulation and planning. The planned cycling operation of the breadboard will provide a real-time orbital cycle lead over the flight vehicle and hopefully identify any chronologically induced anomalies while sufficient time remains to take corrective action or make preventative moves on the flight vehicle. The breadboard system will also offer a platform for analysis of the EPS of the flight vehicle to investigate the source of anomalies observed during flight. The AXAF-I EPS testbed utilizes three Ni-H₂ batteries composed of cells from the same build lot as the cells in the batteries on the flight vehicle. Operation of the breadboard EPS with the flight type Ni-H₂ batteries is scheduled to begin early June 1997; the launch of the AXAF-I spacecraft is scheduled for summer 1998. This paper discusses the design and assembly of the AXAF-I EPS breadboard testbed with an emphasis on the design and performance of the Ni-H₂ batteries