@anildash Thanks for writing this. NASA has (or has had in the past) over thirty Flickr accounts for various things. They're not all active (though some are) but it's a huge number of public domain or CC-licensed images. If you start from this query you can see some of them up top (further down, just people using the name or talking about something else altogether). https://www.flickr.com/search/people/?username=NASA