The first non-photo camera sensors mounted on unmanned spacecraft were aboard satellites devoted mainly to looking at clouds. Superimposed on the cloud patterns is a generalized weather map for the region. Then, in the 1960s as man entered space, cosmonauts and astronauts in space capsules took photos out the window. In time, the space photographers had specific targets and a schedule, although they also have some freedom to snap pictures at targets of opportunity. During the '60s, the first sophisticated imaging sensors were incorporated in orbiting satellites.
Resolution is the size of the smallest contrasting object pairs that can be sharply distinguished.
Below, we show three examples from the Nimbus satellite's sensors to give an idea of how good the early photos were. Such synoptic areas of regional coverage were of great value to the meteorological community, so that many of these early satellites were metsats, dedicated to gathering information on clouds, air temperatures, wind patterns, etc.