tokens: A plan shall be established for the maintenance and periodical review of the budget established in requirement 5.2.2.2c during all project phases . NOTE These budgets take into account : · spacecraft - sun distance , · sun and eclipse durations , · solar aspect angle , · pointing accuracy , · environmental temperature and degradation effects , · reliability and safety aspects , · any one failure in the system ( two failures for manned mission ) not counting solar array string and battery cell failure , · Failure detection , isolation and recovery scenarios .