The home search page for the National Archives is located here: https://www.archives.gov/research/catalog
The rights and permission statement may be found here: https://www.archives.gov/global-pages/privacy.html
The National Archives houses images, documents, film, audio recordings, and other material collected by a multitude of government agencies. As the work of the US government, these items are copyright free and are free for the public to use, although some material that was gifted to NARA has limitations and restrictions. It offers various resources for researchers, including HistoryHub where researchers can collaborate and raise questions about specific archival collections and records (https://historyhub.history.gov/welcome). The site is a good source for information related to US history, government programs, genealogy, and military history.
The NASA Commons site on Flickr is located at: https://www.flickr.com/photos/nasacommons
A rights and permission statement is available on the NASA Images website: https://www.nasa.gov/multimedia/guidelines/index.html
The NASA Commons Flickr site gives access to a selection of copyright-free images, video, and other materials from the NASA archives found on its master website, NASA Images: https://images.nasa.gov/. These images are free to use by the public, with some restrictions as outlined on NASA’s rights and permission page. Most of these restrictions have to do with commercial usage in advertisements or in other ways that might imply NASA’s endorsement of a commercial project. Likeliness rights to individual astronauts or individuals shown in photos may be necessary to obtain as well. The rich library of imagery gives users the ability to draw on NASA’s entire history of space flight and exploration.