English: You may reproduce materials from From Quarks to Quasars for nonprofit and educational purposes only, under the terms and conditions of the definition of "fair use." Proper attribution, including a notice of copyright, must be included on all copies.
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]