Use Of The OTF In The Cost/Performance Evaluation Of Space Telescopes

Abstract

The optical transfer function (OTF) can be used to give the first order performance characteristics of space telescope systems as a function of cost. Using the effective transfer functions of the optical system, instruments, sensors and communication system, a total system transfer function can be defined. Utilizing the properties of the transfer function, specific quality criteria are applied that are measures of certain astro-nomical objectives; such as imaging, photometry, spectroscopy, etc. The specific criteria are then related to a dominant independent variable which is a measure of the scientific objectives such as spatial resolution, at a given contrast level, for imaging and the amount of energy passing through a slit for spectroscopy. These measures can be related to a set of basic astronomical observations that are to be made by that particular telescope. Since nearly every sub-system has a cost-accuracy relationship, we can evaluate changes in subsystems to their corresponding impact on astronomical observations through changes in the transfer function of the system and the quality criteria.