Using Digital Signal Processors on Small Satellites

Digital Signal Processing integrated circuits (DSPs) have improved terrestrial communications systems by allowing the implementation of greatly improved transmitters and receivers. In applications from dial-up modems, to echo-free conference phones, to customer-specific hearing aids, DSPs have allowed the implementation of functions that would be impractical without them. However, DSPs have had limited use in small satellites due to lower available data rates and relatively high power consumption. Also, most of the existing DSPs have not been space qualified. Improvements in semiconductor processes are allowing the construction of integrated circuits (ICs) with much smaller features. In fact, 0.6 micron processes are becoming generally available. Newer DSP ICs based on these processes have greater speeds and greatly reduced power consumption compared to their predecessors. This paper covers the general use of DSP ICs in small satellites, where the power consumption of on-board circuitry must be minimized. It then discusses DSP power consumption, the achievable DSP data rates, general radiation hardness for the existing DSPs, and the advantages and disadvantages of using DSP- based communication 1 systems in small satellites. The paper shows that the power consumption of presently available DSPs is now sufficiently low, and their processor speeds are now sufficiently high for application to some small satellite systems.