Complex sentence: The more sensitive reconnaissance satellites may not be needed to get substantially correct imagery; earth resources satellites may give adequate, or even better detail--reconnaissance satellites tend not to have the multispectral scanners that are best for agricultural or other economic information.
Split into simpler sentences: The more sensitive reconnaissance satellites may not be needed to get substantially correct imagery. Earth resources satellites may give adequate, or even better detail--reconnaissance satellites tend not to have the multispectral scanners that are best for agricultural or other economic information.