The NASA website hosts a large number of images from the Soviet/Russian space agency, and other non-American space agencies. These are not necessarily in the public domain.
The SOHO (ESA & NASA) joint project implies that all materials created by its probe are copyrighted and require permission for commercial non-educational use. [2]
2006-02-09T20:20:11Z Michaelfavor 1006x806 (113573 Bytes) Artist Interpretation of GPS satellite, image courtesy of NASA [[http://www.navcen.uscg.gov/ftp/gps/ggeninfo/gps-iif.tif]]