Revised block II/IIA lifetime predictions and the impact on block IIR/IIF replensihment planning

摘要

Revised lifetime predictions based on on-orbit experience from reaction wheels, colcks, and solar array performance are developed for Block II/IIA satellites. The revised lifetime predictons extend the bsseline Block IIA mean mission duration (MMD) from 6.75 years to 8.45 years. Existing production and launch shcedules for futre Block IIR/IIF satellites evaluated using the new lifetime predictions indicate that there is high near-term availability of 24 satellites, which drops in later years. BY stretching the planned Block IIR launch schedule and maintaining the existing Block IIF production schedule, the availability of 24 satellites can be maintained above 95