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. [1]
This image shows a flag, a coat of arms, a seal or some other official insignia. The use of such symbols is restricted in many countries. These restrictions are independent of the copyright status.
This tag does not indicate the copyright status or the source of the attached work. A normal copyright tag and a source are still required. See Commons:Licensing for more information.