Wait a second. Nasa is the US government. This manual is therefore not protected by copyright, at least not within the US. And they are charging 79$? They can do so, but 79 seems a little high given that once anyone gets their hands on it they can in turn sell their own copies again. How much for the pdf?
"A work of the United States government, as defined by the United States copyright law, is "a work prepared by an officer or employee" of the federal government "as part of that person's official duties."[1] In general, under section 105 of the Copyright Act,[2] such works are not entitled to domestic copyright protection under U.S. law.
This act only applies to U.S. domestic copyright as that is the extent of U.S. federal law. The U.S. government asserts that it can still hold the copyright to those works in other countries.
Publication of an otherwise protected work by the U.S. government does not put that work in the public domain. For example, government publications may include works copyrighted by a contractor or grantee; copyrighted material assigned to the U.S. Government; or copyrighted information from other sources."
