Project Apollo Archive on Flickr
This is so, so wonderful—hundreds and hundreds of photographs from all of the Apollo missions. Gorgeous!
The shots of Earth take my breath away.
ISS Star Trails - a set on Flickr
Beautiful time-lapse photography from Don “we’ve got a Dragon by the tail” Pettit, taken from the International Space Station.
Related links
Flickr: Official SpaceX Photos’ Photostream
SpaceX has a Flickr account, and you have permission to use these photos.
IXS Enterprise (IXS-110) - an album on Flickr
Design fiction from a NASA scientist.
mobilewood - a set on Flickr
We are preparing to launch.
Flickr: NASA on The Commons' Photostream
NASA is now part of Flickr Commons: loads of wonderful science-related pictures with no known copyright restrictions.