Fault-tolerance technique enables a system or application to continue working even if some fault /error occurs in a system. Therefore, it is vital to choose appropriate fault tolerant technique best suited to our application. In case of real-time embedded systems in a space project, the importance of such techniques becomes more critical. In space applications, there is minor or no possibility of maintenance and faults occurrence may lead to serious consequences in terms of partial or complete mission failure. This paper describes the comparison of various fault tolerant techniques for space applications. This also suggests the suitability of these techniques in particular scenario. The study of fault tolerance techniques relevant to real-time embedded systems and on-board space applications (satellites) is given due importance. This study will not only summarize fault tolerant techniques but also describe their strengths. The paper describes the future trends of faults-tolerance techniques in space applications. This effort may help space system engineers and scientists to select suitable fault-tolerance technique for their mission.
