- Ever-increasing demands of space missions for data returns from their limited processing and communications resources have made the traditional approach of data gathering, data compression, and data transmission no longer viable. Increasing on-board processing power by providing high-performance computing (HPC) capabilities using commercial-off-the-shelf (COTS) components is a promising approach that significantly increases performance while reducing cost. However, the susceptibility of COTS components to single-events upset (SEU) is a concern demanding fault-tolerant system infrastructure. Among the components of this infrastructure, message-passing middleware based upon the Message Passing Interface (MPI) standard is essential, so as to support and provide a nearly effortless transition for earth and space science applications in MPI from groundbased computational clusters to HPC systems in space. In this paper, we present the design of a fault-tolerant MPIcompatible middleware for...