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]
Textual information (e.g. timestamp) once visible in the image itself has been moved into the image metadata and/or image description page. This makes the image easier to reuse and more language-neutral, and makes the text easier to process and search for. Commons discourages placing visible textual information in images. All licenses accepted on Commons permit this type of modification as a derivative work.
If attribution information were removed and the image is not public domain, replace this tag with {{Attribution metadata from licensed image}}.