The great strength of the satellite observatory Is its ability to look 

 at the world ocean on a time scale that is small compared with that of 

 many important dynamic processes. This ability is greatest in the case of 

 satellites in earth-synchronous equatorial orbit, but even in low polar 

 orbits of several hundred miles altitude the entire ocean can be overflown 

 at Intervals of less than one day. 



A large assortment of color photographs obtained during the Gemini 

 flights is available at NASA headquarters and at the Manned Spacecraft 

 Center in Houston. Some of these photographs have aooeared in nonscient I f Ic 

 popular magazines, and NASA has published them in an atlas. These pictures 

 show that space resolution Is not limiting from these low orbits. The 

 color photography shoves that the color contrast is adequate for many 

 purposes, such as delineating olumes of silt, mud, pollutants, and oily 

 slicks off river mouths and estuaries, and showing areas of shoal water. 

 Some information about the conditions of the sea surface can be obtained 

 from its reflective properties. It is probable that the visibility of the 

 Gulf Stream reported by Glenn on MA-6 was due to differences In the slopes 

 of the wavelets rather than to differences in the water color itself. By 

 suitable filtering, It Is even possible to photograph the bottom at 

 controlled optical depths, thus providing some information about shallow 

 depth contours, where the color contrasts are very large. 



Over the open sea, color photography has not, as yet, produced much 

 Information of scientific value. Due to atmospheric effects and to the 

 film-processing methods in use, the high seas are shown as brilliant blue, 

 devoid of any recognizable color features. Whether this Is all that can be 



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