scope:

Description of Driving Event:

Two Command and Data Simulator (CADS) checkout computers located in the CADS room are attached to dedicated UPSs. During Space Shuttle Main Engine (SSME) validation, the UPS for the second CADS computer (GSE for SSME testing) was not functioning. This second CADS computer was a backup and had not been used for 2 years. Review of technical specifications revealed that the UPS batteries require full recharge cycling every 6 months in order to keep the batteries from discharging beyond the safe limit. Procedures to perform this maintenance were not in place.