The Facsimile Camera - Its Potential As A Planetary Lander Imaging System

Abstract

The facsimile camera is an optical-mechanical scanning device which is an attractive candidate for planetary lander imaging systems and has been selected for the Viking/Mars mission because of its light weight, small size, and low power requirement. Other advantages are that it can provide good radiometric and photogrammetric accuracy because the complete field of view is scanned with a single photodetector located on or near the optical axis of the objective lens. In addition, this device has the potential capability of multispectral imaging and spectrometric measurements. This can be implemented without increase in mechanical complexity by the use of interference filters and solid-state detector arrays. Some of these potential capabilities of the facsimile camera have been realized in the Viking Lander Camera design; others are currently being investigated for possible application in future missions. This paper reviews the performance characteristics of the facsimile camera, emphasizing its line-scan sampling process; the design trade offs which are imposed by planetary lander missions, emphasizing those trade offs which define the Viking Lander Camera parameters; and new concepts which are currently being investigated for future planetary lander missions, emphasizing an integrated imagery and spectrometry concept.