was orbited and color pictures were received only intermittently. No 

 color pictures were received after January I968. Modification of the 

 ground equipment has produced a clear green signal from the MSSCC and 

 this is used for black and white pictures (see frontispiece). 



The IDCS of ATS 3 consists of a telescope, a vidicon data processor 

 and a sun sensing element. The camera produces a scan line with each 

 revolution of the satellite. Direction of scan, north to south or west 

 to east, is determined by ground command. In the longitudinal (i.e. north 

 to south) mode, 1,328 scan lines provide an earth coverage from 50° N. 

 to 50° S. and from 50° W. to 50° E. of the subsatellite point. West 

 to east scan lines increase the field of view to include the limbs of 

 the earth. Ground resolution is approximately 7.8 km. (U.2 nm. ) at the 

 subsatellite point. 



An IDCS television system similar to that of ATS 3 will be installed 

 on Nimbus B2 scheduled for launching Spring I969 (See Part I, Section 6). 



Although all of the pictures received from the ATS satellites are 

 useful scientifically, aesthetically the most impressive were the color 

 pictures taken by ATS 3's MSSCC. A time-lapse movie made from one day's 

 color pictures gives a vivid example of low level cloud displacement over 

 the ocean as well as conveying the idea of how some of these displacements 

 are influenced by the ocean below. These amazing color pictures of the 

 earth from space have only recently been surpassed in clearness by the 

 photographs taken by the crew of Apollo 8. 



34 



