Abstract. Performance in area step-stare detection is measured primarily by the sensitivity and revisit time. The various steps of the detection process are modeled by simple equations, resulting in approximations for the performance figures of a sensor as a function of the design parameters. A second more difficult problem is to arrive at the basic sensor design parameters given the performance figures of detectable target size and required revisit time. The procedure outlined for doing this is to consider the footprint size as a parametric variable. A family of sensor designs described by simple formulas is the result. A trade-off study can then be used to arrive at the optimum footprint size and optimum design. This process must be repeated for each of the candidate wavebands with a final trade-off selection between these optimum designs.