Spacecraft infrared imaging Principles and applications

This first part of a two-part article deals with the principles of infrared imaging and the applications of these principles. The second part, to appear in July, will discuss the systems of IR imaging and their relation to the spacecraft and mission. The general concept of imaging can best be understood in terms of the source and receiver of electromagnetic radiation, and the differences between an image made by reflected external illumination and by self-emitted luminance. There is then the problem of choosing an appropriate spectral region in terms of the maximum emitted energy, the transmission of the atmosphere, and the characteristics of the receiver scanning. This installment concludes with a review of satellite imaging experiments to date and a description of future applications of these techniques.