Smithsonian Report, 1963. — MacKay 



PLATE 3 



These three stages of flight of three missiles show some common features with plate 1. But 

 here guidance action is continually computed, controlled mainly by the error between 

 the paths of the missile and its target. This guidance action is very similar to that of a 

 tennis player returning a ball. (Photos: top, Crown Copyright; center, Bristol Siddeley; 

 and bottom, Bristol Aircraft.) 



