Spacecraft infrared imaging Systems engineering aspects

The first part of this article, which appeared in the June issue, described the nature of infrared scanners and the results of some satellite IR experiments. In this concluding installment, the parametric relationships between the scanner and the spacecraft are set forth. The suborbital velocity/altitude ratio is fixed for a satellite in a circular orbit. Thus, such parameters as coverage, resolution, and scan rate can be expressed in terms of altitude. Since the signal-to-noise ratio of the sensor output is also a function of many of these same parameters, an evaluation of the IR system performance can be made. Equations are developed for relating the sensor, the mission, and the spacecraft in terms of an overall IR system.