NASA's Deep Space 1 spacecraft approaching the comet 19P/Borrelly. Its primary mission was to serve as a technology demonstrator -- testing ion propulsion and 11 other advanced technologies -- successfully completed in September 1999.[1]archive copy at the Wayback Machine
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. [4]