Gregory Maxwell a écrit :
When I pointed out that material related to the ESA should be Free I wasn't attempting to make some grand argument about freedom, but rather a more pragmatic reflection on the nature of space programs: They aren't in business to generate pretty pictures,
That's exactly one of the problems. Since their line of work is building launchers and the like, they've largely off-loaded the tasks of taking pictures and maintaining pictures databases to external contractors. Also, since their job is not to provide a database of pictures free for advertisers to use, they buy the rights to these pictures from the external contractors only for information and education purposes. Buying them for all possible commercial uses, even if possible, would be more costly and wouldn't be in their scope of work.