NASA not Nasa. It’s an acronym not a word.
"A growing convention, which I first came across in Robert Bringhurst’s The Elements of Typographic Style, dictates that if an acronym is pronounced as a word, then it should not be written in all caps. (As opposed to initialisms, which are pronounced as a series of letters. Compare Nato to USA.)"
http://scratchtap.com/when-acronyms-should-not-be-capitalize...