Also, IIRC, as soon as you patent something then even though people can't make it without paying you a royalty the patent is available for anyone to read.

Bearing in mind a fair amount of what NASA does is going to be largely top secret would you really want to patent stuff?

 

In the UK you can classify patents for national security reasons. Not had much involvement in that side of things, but I have worked on MOD PFI projects which have involved any patentable inventions being submitted to a particular division of the Patents Office.