Abstract: The communication satellites deployed in geosynchronous orbit are expensive and the orbital resources are scare. The influence range of onorbit mission is wide and the reliability requirements are high. Based on the fact that the acutal life of some spacecraft in orbit is generally higher than the design life,it designs the theory life of geosynchronous orbit communication satellite offorbit backup scheme and studies the using mode,constraint conditions and backup efficiency of offorbit satellite, which can provide reference for the onorbit backup design other geosynchronous orbit satellites.

Key words: GEO satellite, end of litetime, deorbit backup, reconstruct