NASA is the U.S. government agency responsible for space exploration and designing new technologies to achieve it. NASA is not known for digital publishing, but a recent article on the website Good Ereader highlights that the agency is quietly building an eBook empire. NASA eBooks started in the last decade. The eBooks are all 100% free and are available in EPUB, MOBI, and PDF formats, allowing them to be read on any e-reader, tablet or smartphone. The subject matters deal mostly with aeronautics and other sciences.

You can read more about NASA eBooks here, or you can access NASA eBooks directly here.