A Generic Guidance, Navigation, And Control System For Low Cost Launch Vehicles


Reflections To The Future highlights the need for low cost Guidance, Navigation, and Control (GN&C) systems, suitable for use on simple sounding rockets and vehicles up through orbital insertion. Microcosm has designed and built such a low cost GN&C system in support of the NASA-Marshall SR-S sounding rocket. The SR-S concept is based on earlier Microcosm work toward low cost space programs. In recognition that launch vehicle development costs plus operational costs far exceed unit build costs, all costs, including the GN&C overall life-cycle cost, were attacked. Design of a GN&C system that truly minimizes cost required that development and operational aspects be part of the design cost. This, in turn, required a clean-sheet approach, resulting in adoption and use of Commercial-Off-The-Shelf (COTS) components, hardware and software technology. The GN&C modularity concept calls for changes in configuration from vehicle to vehicle to be cable/interconnected-enabled, and changes from mission to mission to be software-enabled. This concept called for innovation, with modular design that avoided expensive and complicated integration and optimization. Several interesting technological approaches are described in this paper: 1) use of GPS technology, 2) use of reusable Generic Guidance Navigation and Control system, 3) a special purpose Digital Flight Computer of general capability, combining the Flight Computer with smart, distributed Electronic Controllers, and 4) a cost-conscious system design and development strategy. The system design and development strategy involved choosing components that, together, provide the lowest life-cycle cost with adequate performance. Modularity and scaleability principles are described which promise future reusability at system, equipment, module, and component levels, including dual-string reliability for orbital launches.