Yes. At least in the case of American satellites. Basically all information produced by the US (federal) Government that is not classified is in the public domain.[1] There are all sorts of weaselly ways that companies and in some cases government agencies try to limit this (for example, West Publishing, the company that publishes laws has copyright on the page numbers which are needed to reference those laws[2]), but in this case we're talking about raw data, transmitted on public airwaves, so there is really no question that it's in the public domain.

[1] https://en.wikipedia.org/wiki/Copyright_status_of_works_by_t...

[2] https://www.wired.com/1994/05/the-law/