- Use of NASA logos (which include the current "meatball" logo, the old "worm" logo, and the seal) is restricted.
- The NASA website hosts a large number of images from the Soviet/Russian space agency, and other non-American space agencies. These are not in the public domain.
- Materials from the Hubble Space Telescope may be copyrighted if they do not explicitly come from the STScI. 
- All materials created by the SOHO probe are copyrighted and require permission for commercial non-educational use. 
- Images featured on the Astronomy Picture of the Day (APOD) web site may be copyrighted.