NASA vs ESA
To summarize the differences between NASA and ESA/CNES:
- Fear of use for advertisement, propaganda etc.
- NASA's work are public domain. However, US law severely restricts the use of NASA and other US government logos and insignia in advertisement and propaganda contexts. As a result, NASA needs not fear inappropriate use of their pictures.
- In contrast, ESA, CNES and other European agencies do not enjoy similar legal protections from inappropriate use. They are concerned that some commercial companies, or some politicians, may use photographs of their craft etc. and they may have trouble fighting that in court. As a consequence, they prefer to use copyright to prevent the inappropriate use of their photographs, and are prepared to impose licensing conditions similar to "free for any use, any commercial, as long as it is informational or educational".
- Authors of the works
- NASA employs a wide array of photographers and imposes liberal licensing terms to contractors.
- ESA has few photographers; many photographs (of launches etc.) are taken by independents, who then license them to ESA under terms such as "free for any use, any commercial, as long as it is informational or educational", but excluding e.g. commercial advertisements.
- Note that, anyway, the bylaws of the Wikimedia Foundation explicitly state that this Foundation restricts itself to "educational content".