On Convergence of Development Costs and Cost Models for Complex Spaceflight Instrument Electronics

Development costs of a few recent spaceflight instrument electrical and electronics subsystems have diverged from respective heritage cost model predictions. The cost models used are grass roots, price-H [1] and parametric model [3]. These cost models originated in the military and industry around 1970 and were successfully adopted and patched by NASA on a mission-by-mission basis for years [2]. However, the complexity of new instruments recently changed rapidly by orders of magnitude. This is most obvious in the complexity of representative spaceflight instrument electronicspsila data system. It is now required to perform intermediate processing of digitized data apart from conventional processing of science phenomenon signals from multiple detectors. This involves onboard instrument formatting of computational operands from row data (for example, images), multi-million operations per second on large volumes of data in reconfigurable hardware (in addition to processing on a general purpose embedded or stand-alone instrument flight computer), as well as making decisions for onboard system adaptation and resource reconfiguration. The conflict between the actual development cost of newer complex instruments and its electronics componentspsila heritage cost model predictions seems to be irreconcilable. This conflict and an approach to its resolution are addressed in this paper by determining the complexity parameters, complexity index, and their use in enhanced cost model. It is expected to facilitate farther enhancements to existing cost models, resulting in smaller difference (convergence) between the electronicspsila developmental and model predicted costs.